We provide electric charges and fields practice exercises, instructions, and a learning material that allows learners to study outside of the classroom. We focus on electric charges and fields skills mastery so, below you will get all questions that are also asking in the competition exam beside that classroom.

#### List of electric charges and fields Questions

Question No | Questions | Class |
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1 | Which of the following assertions are correct? This question has multiple correct options A. ( A ) neutron can decay to a proton only inside a nucleus. B. ( A ) proton can change to a neutron only inside a nucleus. C. An isolated neutron can change into a proton. D. An isolated proton can change into a neutron. |
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2 | A large sheet of uniform charge passes through a hypothetical spherical surface. The figure shows principle section of situation. The electric flux through the spherical surface is given by ( ^{mathbf{A}} cdot frac{pi R^{2} sigma}{epsilon_{0}} ) B. ( frac{2 pileft(R^{2}-x^{2}right) sigma}{epsilon_{0}} ) ( c ) ( D ) |
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3 | Four identical pendulums are made by attaching a small ball of mass 100 g on a ( 20 mathrm{cm} ) long thread and suspended from the same point. Now each ball is given charge ( Q ) so that balls move away from each other with each thread making an angle of ( 45^{circ} ) from the vertical. The value of ( Q ) is close to ( left.frac{1}{4 pi epsilon_{0}}=9 times 10^{9} text { in Sl units }right) ) A . ( 1 mu C ) в. ( 1.5 mu ) С ( c cdot 2 mu c ) D. 2.5 ( mu ) C |
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4 | A uniform nonconducting rod of mass ( mathrm{m} ) and length ( l, ) with charge density ( lambda ) as shown in figure, is burged at the midpoint at origin so that it can rotate in a horizontal plane without any friction. A uniform electric field E exists parallel to x-axis in the entire region. Calculate the period of small oscillations of the rod |
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5 | Two conducting spheres of radii ( r_{1} ) and ( r_{2} ) are equally charged. The ratio of their potentials is : A ( cdot r_{1} / r_{2} ) в. ( r_{2} / r_{1} ) ( mathbf{c} cdot r_{1}^{2} / r_{2}^{2} ) ( mathbf{D} cdot r_{2}^{2} / r_{1}^{2} ) |
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6 | Electrical charge can be transferred from a charged object to another through A. vacuum B. air c. insulator D. conductor |
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7 | A cube has sides of length ( L=0.2 mathrm{m} ). It is placed with one corner at the origin as shown in figure.The electric field is uniform and given by ( overrightarrow{boldsymbol{E}}= ) ( (2.5 N / C) dot{I}-(4.2 N / C) j . ) Find the electric flux through the entire cube. |
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8 | Consider the charge configuration and a spherical Gaussian surface as shown in the figure. When calculating the flux of the electric field over the spherical surface, the electric field will be? ( mathbf{A} cdot ) Due to ( q_{2} ) B. Only due to the positive charges c. Due to all the charges D. Due to ( +q_{1} ) and ( -q ) |
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9 | Two point charges ( +q ) and ( +q ) are fixed at ( (a, 0,0) ) and ( (-a, 0,0) . ) A third point charge ( -q ) is at origin. State whether its equilibrium is stable, unstable or neutral if it is slightly displaced along ( boldsymbol{x}- ) axis. A . Stable B. Unstable c. Neutral D. Data insufficient |
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10 | There are how many kinds of charges? A. one B. Two c. Three D. Four |
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11 | A charge ( Q ) is placed at the corner of a cube. The electric flux through all the faces of the cube is ( mathbf{A} cdot Q / varepsilon_{0} ) в. ( Q / 6 varepsilon_{0} ) c. ( Q / 8 varepsilon_{0} ) D. ( Q / 3 varepsilon_{0} ) |
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12 | Eight dipoles of charges of magnitude ( e ) are placed inside a cube. The total electric flux coming out of the cube will be ( A cdot frac{8 e}{varepsilon_{0}} ) В. ( frac{16 e}{varepsilon_{0}} ) ( c cdot frac{e}{varepsilon_{0}} ) D. zero |
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13 | The angle between the dipole moment and electric field at any point on the equatorial plane is : A ( cdot 0^{circ} ) B. 90 c. ( 180^{circ} ) D. ( 45^{circ} ) |
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14 | A point charge ( +Q ) is placed at point 0 as shown in the figure. Is the potential difference ( V_{A}-V_{B} ) positive, negative or zero? |
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15 | Two short dipoles moment P are placed at two corners of a square as shown in the figure. What is the ratio of magnitudes of electric field at two points 0 and ( A ? ) ( A cdot 2 ) B. ( 2 sqrt{2} ) ( c ) D. ( sqrt{2} ) |
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16 | Which of the following is an electrica insulator: A. Aluminium B. Gold c. Rubber D. None of these |
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17 | ( boldsymbol{epsilon}_{0} ) is known as the A. electrical permeability of free space B. electrical permittivity of free space C. magnetic permeability of free space D. None of these |
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18 | A particle of mass ( mathrm{m} ) and charge ( boldsymbol{q} ) is thrown in a region where uniform gravitational field and electric field are present. The path of particle : This question has multiple correct options A. may be straight line B. may be a circle c. may be a parabola D. may be a hyperbola |
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19 | An electric dipole of moment p is kept along an electric field E. The work done in rotating it from an equilibrium position by an angle ( boldsymbol{theta} ) is : ( A cdot P E(1-cos theta) ) B. PE(1 – ( sin theta ) ) c. ( P E cos theta ) D. PE sin ( theta ) |
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20 | An electric filament bulb can be worked from A. DC supply only B. AC supply only c. Battery supply only D. All above |
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21 | A moving charge produces. A. Only electric field B. Only magnetic field C. Both electric and magnetic fields D. Neither the electric field nor the magnetic field |
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22 | A sure test of electrification is: A . attraction B. repulsion c. friction D. induction |
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23 | A particle having a charge of ( 10 mu C ) and mass ( 1 mu g ) moves in a horizontal circle of radius ( 10 mathrm{cm} ) under the influence of a magnetic field of 0.1 T. When the particle is at a point ( P, ) a uniform electric field is switched on so that the particle starts moving along the tangent with uniform velocity. The electric field is A. ( 0.1 mathrm{V} / mathrm{m} ) B. 1.0 ( mathrm{V} / mathrm{m} ) c. ( 10.0 mathrm{V} / mathrm{m} ) D. ( 100 mathrm{V} / mathrm{m} ) |
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24 | Two coaxial coils are very close to each other and their mutual inductance is 5 ( mathrm{mH} ). If a current ( 50 sin 500 r ) is passed in one of the coils then the peak value of induced e.m.f. in the secondary coil will be? A . ( 5000 v ) в. ( 500 v ) ( c .150 v ) D. 125v |
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25 | Electric intensity due to a charged sphere at a point outside the sphere decreases with A. increase in charge on sphere B. increase in dielectric constant c. decrease in the distance from the centre of sphere D. decrease in square of distance from the centre of sphere |
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26 | Which of the following statements are true: A: Charge cannot exist without mass but mass can exist without charge B: Charge is invariant but mass varies with velocity C: Charge is conserved but mass alone may not be conserved ( A cdot A, B, C ) are true B. A, B, C are not true c. ( A, B ) are only true D. ( A, B ) are false, ( C ) is true |
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27 | If the magnitude of intensity of electric field at a distance ( x ) on axial line and at a distance ( y ) on equational line on a given dipole are equal, then ( x: y ) is ? |
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28 | An electric dipole is held in a uniform electric field. (i) Show that the net force acting on it is zero (ii) The dipole is aligned parallel to the field. Find the work in rotating it through the angle of ( 180^{circ} ) |
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29 | Which of the following is not a unit of charge? A. coulomb B. ampere-second c. microcoulomb D. ampere/second |
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30 | An infinite number of charges each equal to ( q ) are placed along the ( x ) -axis at ( boldsymbol{x}=mathbf{1}, boldsymbol{x}=mathbf{2}, boldsymbol{x}=mathbf{4}, boldsymbol{x}=mathbf{8} ) and ( mathbf{s} mathbf{o} ) on Find the potential and electric field at the point ( x=0 ) due to this set of charges. A ( cdot_{5 k q}, frac{4 k g}{3} ) в. ( 2 k q, frac{4 k g}{3} ) c. ( _{3 k q}, frac{4 k g}{3} ) D. ( 7 k q, frac{4 k g}{4} ) |
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31 | The bob of a pendulum is positively charged. Another identical charge is placed at the point of suspension of the pendulum. The time period of pendulum A. increases B. decreases c. becomes zero D. remains same |
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32 | Rub a piece of ebonite across a piece of animal fur. What happens? A. the fur has a slightly positive charge and the ebonite is slightly negative B. the fur has a slightly positive charge and the ebonite is also slightly positive C. the fur has a slightly negative charge and the ebonite is also slightly negative D. the fur has a slightly negative charge and the ebonite is slightly positive |
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33 | Consider two concentric spherical metal shells of radii ‘a’ and b> a. The outer shell has charge ( Q, ) but the inner shell has no charge,Now,the inner shell is grounded. This means that the inner shell will come at zero potential and that electric fields lines leave the outer hell and end on the inner shell. |
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34 | State the effect on the divergence of the leaves of a gold leaf electroscope on bringing a negatively charged rod near it if the electroscope is negatively charged: A. Divergence decreases B. Divergence increases c. Divergence remains same D. can’t say |
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35 | An electron is projected from a distance ( d ) and with initial velocity ( u ) parallel to a uniformly charged flat conducting plate as shown. It strikes the plate after travelling a distance ( ell ) along the direction of projection. The surface charge density of the conducting plate is equal to A ( cdot frac{2 d varepsilon_{0} m u^{2}}{e ell^{2}} ) B. ( frac{2 d varepsilon_{0} m u}{e ell^{2}} ) c. ( frac{d varepsilon_{0} m u^{2}}{e ell} ) D. ( frac{d varepsilon_{0} m u}{e l} ) |
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36 | How will you determine the electric field a any point along the axial line of an electric dipole. |
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37 | (a) Which physical quantity has its ( mathrm{S} ) I unit ( (1) mathrm{Cm}(2) mathrm{N} / mathrm{C} ) (b) Two point charges ( q ) and ( -q ) is placed at a distance ( 2 a ) apart. Calculate the electric field at a point ( P ) is situated at a distance r along the perpendicular bisector of the line joining the charges. What is the electric field when ( r>> ) a? Also, give the direction of electric field w.r.t. electric dipole moment? |
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38 | The electric potential ( V ) at any point ( (x, y, z) ) in space is given by ( V=3 x^{2} ) where ( x, y, z ) are all in metre. The electric field at the point ( (1 m, 0,2 m) ) is A ( cdot 6 V m^{-1} ) along negative ( x ) -axis B. ( 6 V m^{-1} ) along positive ( x ) -axis C. ( 12 mathrm{Vm}^{-1} ) along negative ( x ) -axis D. ( 12 mathrm{Vm}^{-1} ) along positive ( x ) -axis E. ( 8 mathrm{Vm}^{-1} ) along negative ( x ) -axis |
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39 | Two point charges ( +3 mu C ) and ( +8 mu C ) repel each other with a force of ( 40 N . ) If a charge of ( -5 mu C ) is added to each of them, the force between them will become: A ( .-10 N ) B. ( 10 N ) ( c .20 N ) D. ( -20 N ) |
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40 | The law that describes the force as directly proportional to magnitude of charges and inversely proportional to the distance between the charges is known as: A. Newton’s law B. Coulomb’s law c. Gauss’s law D. Ohm’s law |
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41 | If the electric field at points In between, and is ( K sigma / varepsilon_{0} . ) Find ( mathrm{K} ? ) |
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42 | Ordinary rubber is an insulator. But the special rubber tyres of aircrafts are made slightly conducting. Why is this necessary? |
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43 | An electric dipole of diploe moment ( overrightarrow{boldsymbol{p}} ) placed in uniform electric field ( overrightarrow{boldsymbol{E}} ) has minimum potential energy when angle between ( vec{p} ) and ( overrightarrow{boldsymbol{E}} ) ( ^{A} cdot frac{pi}{2} ) B. zero c. ( pi ) D. ( frac{3 pi}{2} ) |
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44 | A body is brought near to a negatively charged gold leaf electroscope. If the divergence of leaves increases. What is the nature of charge on the body? A. Positive B. Negative c. No charge D. cant say |
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45 | From the schematic electric field lines, we can infer that A. the left charge is higher in magnitude than the right one B. the left charge is lower in magnitude than the right one c. the left charge is equal in magnitude to the right one D. None of these |
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46 | A ball of radius R carries a positive charge whose volume charge density depends only on the distance r from the ball’s centre as: ( rho=rho_{0}left(1-frac{r}{R}right) ) where ( rho_{0} ) is constant. Assume ( epsilon ) as the permittivity of the ball. Then the magnitude of the electric field as a function of the distance r outside the ball is given by : A. ( quad E=frac{rho_{0} R^{3}}{8 epsilon r^{2}} ) в. ( quad E=frac{rho_{0} R^{3}}{12 r r^{2}} ) c. ( _{E=frac{rho_{0} R^{3}}{16 epsilon^{2}}} ) D. ( quad E=frac{rho_{0} R^{3}}{24 r^{2}} ) |
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47 | What is the net charge on an neutral atom? A. positive B. negative c. zero D. none of these |
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48 | A negative charged object reples another charged object kept close to it. What is the nature of the charge on the other object? A. positive B. negative c. both D. none |
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49 | A charged glass rod will get discharged on A. connecting it to the earth B. connecting it to another glass rod c. breaking the ends of the rod D. Any of the above |
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50 | Determine the electric field everywhere outside the sphere at a distance ( r(>> ) ( boldsymbol{a}) ) from the centre A ( cdot E=frac{Q}{4 pi epsilon_{0} r^{2}} ) B. ( quad E=frac{Q}{4 pi epsilon_{0} r} ) c. ( quad E=frac{Q}{4 pi epsilon_{0} a^{2}} ) D. ( quad E=frac{Q}{4 pi epsilon_{0} a} ) |
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51 | An electric dipole of momentum ( vec{p} ) is placed in a uniform electric field. The dipole is rotated through a very smal angle from equilibrium and is released. Prove that it executes simple harmonic motion with frequency ( f=frac{1}{2 pi} sqrt{frac{p E}{1}} ) Where, ( I= ) moment of inertia of the dipole. |
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52 | Three long wires with same current placed at three corners of an equilateral triangles as shown in figure then the magnetic field at the centre of the triangle will be (side length of triangle is a) |
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53 | A pith ball of mass ( 9 times 10^{-5} k g ) carries a charge of ( 5 mu C ). What must be charge on another pith ball placed directly ( 2 mathrm{cm} ) above the pith ball such that they are held in equilibrium? A . ( 3.2 times 10^{-11} C ) B . ( 7.84 times 10^{-12} C ) c. ( 1.2 times 10^{-13} C ) D. ( 1.6 times 10^{-19} C ) |
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54 | As one penetrates through uniformly charged conducting sphere, what happens to the electric field strength: A. decreases inversely as the square of the distance B. decreases inversely as the distance c. becomes zero D. increases inversely as the square of distance |
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55 | Three points charges are placed at the corners of an equilateral triangle of side ( L ) shown in the figure. This question has multiple correct options A. The potential at the centroid of the triangle is zero B. The electric field at the centroid of the triangle is zero C. The dipole moment of the system is ( sqrt{2} q L ) D. The dipole moment of the system is ( sqrt{3} q L ) |
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56 | There are two charges ( +2 mu C ) and ( – ) ( 3 mu C . ) The ratio of forces acting on them will be A .2: 3 B. 1: 1 c. 3: 2 D. 4: 9 |
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57 | Two free positive charges ( 4 q ) and ( q ) are at a distance ( l ) apart. What charge ( Q ) is needed to achieve equilibrium for the entire system and where should it be placed from charge ( q ? ) ( left.^{mathbf{A}} cdot Q=frac{4}{9} q quad text { (negative at } frac{l}{3}right) ) ( left.^{mathrm{B}} Q=frac{4}{9} q quad text { (positive at } frac{l}{3}right) ) ( left.^{mathrm{c}} Q=q quad text { (positive at } frac{l}{3}right) ) ( left.^{mathrm{D}} Q=q quad text { (negative at } frac{l}{3}right) ) |
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58 | Fig. shows a point charge of ( 0.5 times 10^{-6} ) ( mathrm{C} ) at the center of the spherical cavity of radius ( 3 c m ) of a piece of metal. The electric field at : This question has multiple correct options A. A (2cm from the charge) is 0 B. A (2 cm from the charge) is ( 1.125 times 10^{7} mathrm{NC}^{-1} ) C. B ( ( 5 mathrm{cm} ) from the charge ) is 0 D. B (5cm from the charge) is ( 1.8 times 10^{6} mathrm{NC}^{-1} ) |
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59 | Which of the following is/are bad conductors of heat?
This question has multiple correct options |
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60 | ( A ) and ( B ) are two identical spherical charged bodies which repel each other with force ( F, ) kept at a finite distance apart A third uncharged sphere of the same size is brought in contact with sphere ( mathrm{B} ) and removed. It is then kept at mid-point of ( A ) and ( B ) find the magnitude of force on ( mathbf{C} ) ( A cdot F / 2 ) B. F/8 ( c cdot F ) D. zero |
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61 | A region in space has a total charge ( Q ) distributed spherically such that the volume charge density ( rho(r) ) is given by ( boldsymbol{rho}(boldsymbol{r})=boldsymbol{3} boldsymbol{a} boldsymbol{r}(boldsymbol{2} boldsymbol{R}) ) for ( r leq frac{R}{2} ) ( boldsymbol{rho}(boldsymbol{r})=boldsymbol{a}left[mathbf{1}-left(frac{r}{R}right)^{2}right] quad ) for ( frac{R}{2} leq r leq ) ( boldsymbol{R} ) ( rho(r)=0 ) for ( r>R ) Find the electric field at ( rholeft(frac{R}{2}<x<Rright) ) |
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62 | Three small spheres, each carrying a charge ( q ) are placed on the circumference of a circle of radius ( R ) forming an equilateral triangle. If we place another charge ( Q ) at the center of the circle, then the force on ( Q ) will be A. zero В. ( frac{1}{4 pi epsilon_{0}} times frac{q Q}{R^{2}} ) c. ( frac{1}{4 pi epsilon_{0}} times frac{2 q Q}{R^{2}} ) D. ( frac{1}{4 pi epsilon_{0}} times frac{3 q Q}{R^{2}} ) |
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63 | The total flux passing through the cube is A ( .-0.135 N m^{2} C^{-1} ) B . ( -0.054 N m^{2} C^{-1} ) ¿. ( 0.081 N m^{2} C^{-} ) D. zer |
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64 | 0 | 12 |

65 | The net charge inside an isolated system is A. conserved B. variable c. zero D. infinite. |
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66 | 8 asic placed at a point ( O . ) The arrows show the direction of the magnetic moment. The other arrows show different positions (and orientations of the magnetic moment) of another identical magnetised needle ( Q ). The dotted line represent a circle centre at the midpoint of ( boldsymbol{P} ) Which configuration in this system corresponds to stable equilibrium? ( mathbf{A} cdot P Q_{1}, P Q_{3} ) B. ( P Q_{3}, P Q_{5} ) ( mathbf{c} cdot P Q_{2}, P Q_{4} ) D. ( P Q_{2}, P Q_{3} ) |
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67 | Five point charges, each of value ( +q ) are placed on five vertices of a regular hexagon of side L. What is the magnitude of the force on a point charge of value -q placed at the centre of the hexagon? | 12 |

68 | If a soap bubble, having radius ( r, ) is charged to a charge density ( sigma ) and its increased to ( R ), then ( R ) equals to ( [T ) is the surface tension] A ( cdot R=frac{9 varepsilon_{0} T}{sigma^{2}} ) в. ( quad R=frac{8 varepsilon_{0} T}{sigma^{2}} ) c. ( R=frac{10 varepsilon_{0} T}{sigma^{2}} ) D. ( R=frac{11 varepsilon_{0} T}{sigma^{2}} ) |
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69 | A point charge ( q ) is palced on vertex of right circular cone. the semi-vertical angle of cone A. ( frac{q}{epsilon_{0}} ) в. ( frac{q}{2 epsilon_{0}} ) c. ( frac{q}{3 epsilon_{0}} ) D. ( frac{q}{4 epsilon_{0}} ) |
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70 | A solid non conducting sphere charged in such a way that in it as we move away from the centre, the electric field decreases then which of the following statement is correct : A. the sphere in uniformly charged B. the potential at surface is less than that at its centre c. the potential at surface is more than that at its centre D. the potential at surface may be less than that at its centre |
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71 | Two plastic drinking straws are vigorously rubbed with a piece of wool Then they are brought near each other as shown above. What observation con you make? A. They attract eachother B. They repel eachother c. nothing will happen D. can’t say |
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72 | If one penetrates a uniformly charged spherical cloud, electric field strength A. Decreases directly as the distance from the centre B. Increases directly as the distance from the centre c. Remains constant D. None of the above |
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73 | A gold leaf electroscope is given a positive charge so that its leaves diverge. How is the divergence of leaves affected, when a glass rod rubbed with silk is rolled on the disc of electroscope? A. divergence increases B. divergence decreases c. divergence remains same D. can’t say |
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74 | When a glass rod is rubbed with silk, the charge acquired by the silk is : A. negative B. positive c. partly positive and partly negative D. none of these |
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75 | The electric potential due to a dipole at a point on the perpendicular bisector of its length is : A. maximum B. minimum c. 0 D. None of these |
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76 | A dipole is placed in a shell as shown Find the electric flux emerging out of the shell and in a hypothetical sphere of radius r as shown. A. ( frac{2 q}{8} ) В ( cdot frac{q}{varepsilon_{0}}, frac{-q}{varepsilon_{0}} ) c. ( frac{-q}{varepsilon_{0}}, frac{q}{varepsilon_{0}} ) 0.0 |
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77 | It is required to hold equal charges, ( boldsymbol{q} ) in equilibrium at the corners of a square. What charge when placed at the centre of the square will do this? |
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78 | The gold leaves of a gold-leaf electroscope are enclosed in a glass bottle A. to protect the gold leaves from drafts of air. B. to protect the gold leaves from rusting. c. To protect the gold leaves from wear and tear. D. All of the above |
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79 | Four point charges ( Q, q, Q ) and ( q ) are placed at the corners of a square of side ( a^{prime} ) as shown in the figure. Find the (a) resultant electric force on a charge ( Q, ) and (b) potential energy of this system. |
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80 | Assertion Electron revolves around a positively charged nucleus like a planet revolves around the sun. Reason The force acting in both the cases is of same kind. A. Both Assertion and Reason are correct and Reason is the correct explanation for Assertion B. Both Assertion and Reason are correct but Reason is not the correct explanation for Assertion c. Assertion is correct but Reason is incorrect D. Both Assertion and Reason are incorrect |
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81 | Three concentric spherical metallic shells ( A, B ) and ( C ) of radii ( a, b ) and ( c(c>b ) a) have charge densities ( sigma,-sigma ) and ( sigma ) respectively.The potential of shell B is : A ( cdot(a+b+c) frac{sigma}{varepsilon_{0}} ) B ( cdotleft(frac{a^{2}}{b}-b+cright) frac{sigma}{varepsilon_{0}} ) ( ^{mathbf{c}} cdotleft(frac{a^{2}}{c}-frac{b^{2}}{c}+cright) frac{sigma}{varepsilon_{0}} ) D. ( frac{sigma c}{varepsilon_{0}} ) |
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82 | density ( +sigma ) and ( -sigma ) are parallel to each other as show in figure. Electric field at the This question has multiple correct options A. points to the left or to the right of the sheets is zero. B. midpoint between the sheets is zero. C. midpoint of the sheets is ( sigma / varepsilon_{0} ) and is directed towards right D. midpoint of the sheets is ( 2 sigma / varepsilon_{0} ) and is directed towards right |
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83 | In the figure shown below the conducting shell ( A ) having radius ( R ) is given charge ( Q ) initially. The shell ( A ) is connected to shell ( B ) of radius ( 2 R ) via switch ( S ) and a conducting wire. The switch ( S ) is closed at ( t=0, ) then charge density on the shell ( B ) is (Assuming separation between ( boldsymbol{A} ) and ( B ) is very very large) ( A ) в. ( frac{Q}{24 pi R^{2}} ) c. ( frac{Q}{12 pi R^{2}} ) D. ( frac{Q}{6 pi R^{2}} ) |
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84 | When a piece of polythene is rubbed with wool, a charge of ( -2 times 10^{-7} C ) is developed on polythene. What mass is transferred to polythene? ( mathbf{A} cdot 5.69 times 10^{-19} k g ) B . ( 2.25 times 10^{-19} k g ) ( mathbf{c} cdot 9.63 times 10^{-19} k g ) D. ( 11.38 times 10^{-19} mathrm{kg} ) |
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85 | In identical mercury droplets charged to the same potential ( V ) coalesce to form a single bigger drop. The potential of the new drop will be: A ( cdot frac{V}{n} ) в. ( n V ) c. ( N V^{2} ) D. ( frac{2}{n^{3} V} ) |
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86 | Three identical small balls, each of mass ( 0.1 mathrm{g}, ) are suspended at one point on silk thread having a length of ( 1= ) 20cm. What charges should be imparted to the balls for each thread to form an angle of ( alpha=30^{circ} ) with the vertical? |
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87 | A charge ( Q ) is placed at a distance ( a / 2 ) above the centre of the square surface of edge a as shown in the figure. The electric flux through the square surface is : A ( cdot frac{Q}{3 epsilon_{0}} ) в. ( frac{Q}{6 epsilon_{0}} ) c. ( frac{Q}{2 epsilon_{0}} ) D. ( frac{Q}{epsilon_{0}} ) |
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88 | Electric potential on the surface of a hollow conducting sphere is V. The electric potential is ( frac{V}{2} ) at a distance A ( cdot frac{R}{2} ) inside the sphere B. ( frac{R}{2} ) from the surface of the sphere and outside it C. ( 2 mathrm{R} ) from the centre of the sphere D. ( 2 mathrm{R} ) from the surface of the sphere and outside it |
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89 | A charge ( Q ) is distributed over two concentric hollow spheres of radii ( r ) and ( R(R>r) ) such that their surface densities are equal. The charge on smaller and bigger shells are: A. ( frac{Q r^{2}}{r^{2}+R^{2}} ) and ( frac{Q R^{2}}{r^{2}+R^{2}}, ) respectively в. ( Qleft(1+frac{r^{2}}{R^{2}}right) ) and ( Qleft(1+frac{R^{2}}{r^{2}}right) ), respectivel ( ^{mathrm{c}} Qleft(1-frac{r^{2}}{R^{2}}right) ) and ( Qleft(1-frac{R^{2}}{r^{2}}right) ), respectivel D. ( frac{Q R^{2}}{r^{2}+R^{2}} ) and ( frac{Q r^{2}}{r^{2}+R^{2}}, ) respectively |
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90 | A point charge ( 50 mu C ) is located in the ( x-y ) plane at the position vector ( vec{r}_{0}= ) ( (2 hat{i}+3 hat{j}) m . ) The electric field at the point of position vector ( vec{r}= ) ( (8 hat{i}-5 hat{j}) m, ) in vector from is equal to: A ( cdot 900(-3 hat{i}+4 hat{j}) V / m ) B ( cdot 90(3 hat{i}-4 hat{j}) V / m ) c. ( 9(-3 hat{i}+4 hat{j}) V / m ) D. ( 900(3 hat{i}-4 hat{j}) V / m ) |
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91 | Which among the following is an example of polar molecule? ( A cdot O_{2} ) в. ( H_{2} ) c. ( N_{2} ) D. нс |
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92 | There is an electric field ( boldsymbol{E} ) in ( boldsymbol{X} ) =direction. If work done in moving a charge ( 0.2 C ) through a distance of ( 2 m ) along a line making an angle of 60 degree with ( X ) -axis is 4.0 joule, what is the value of ( boldsymbol{E} ) ? A. ( sqrt{3} ) newton per coulomb B. 4 newton per coulomb c. 5 newton per coulomb D. None of these |
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93 | Lightning is a phenomenon A. Electromagnetic B. Current electricity c. Electrochemical D. Electrostatic |
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94 | Answer the following questions. (i) An electrostatic field line is a continuous curve. That is, a field line cannot have sudden breaks. Why is it so? (ii) Explain why two field lines never cross each other at any point. |
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95 | A charged particle is in the electric field experiences a electric force. All particles which are given below are kept in the electric field of same strength. Which of the following particles would experience the greatest electric force? A. proton B. electron c. alpha particle D. neutron E. photon |
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96 | A charged body is brought near a positively charged gold leaf electroscope. The divergence of its leaves increases. If the same body is brought near a negatively charged gold leaf electroscope, what will be the effect on divergence of its leaves? |
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97 | Two point charge ( Q ) and ( -3 Q ) are placed at some distance apart. If the electric field at the location of ( Q ) is ( vec{E} ), the field at the location of ( -3 Q ) is: A. ( vec{E} ) в. ( -vec{E} ) c. ( +frac{vec{E}}{3} ) D. ( -frac{vec{E}}{3} ) |
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98 | A charged particle is released from rest in a region of steady and uniform electric and magnetic field which are parallel to each other. The nature of light A . circle B. Parabola c. Straight line D. Helix |
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99 | An electric dipole of moment ( overrightarrow{boldsymbol{p}} ) is placed at the origin along the ( x ) -axis. The angle made by electric field with ( x ) axis at a point ( P, ) whose position vector makes an angle ( theta ) with ( x ) -axis, is (where ( left.tan alpha=frac{1}{2} tan thetaright) ) ( A cdot alpha ) B. ( theta ) ( c cdot theta+alpha ) D. ( theta+2 alpha ) |
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100 | Two identical charges of magnitude ( +mathrm{Q} ) are fixed as shown.A third charge – ( Q ) is placed mid way between them at point P. Then small displacements of – Q are made in the directions indicated by arrows. The -Q is stable with respect to displacement . ( odot ) (out of the What is and A . I and III B. I and c. ॥ and ( I V ) D. III and ( v ) E. stable for any small displacement |
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101 | Three equal charges, each having a magnitude of ( 2.0 times 10^{-6} C ) are placed at the three corners of a right angled triangle of sides ( 3 mathrm{cm}, 4 mathrm{cm} ) and ( 5 mathrm{cm} ) The force (in magnitude) on the charge at the right angled corner is : ( A .50 N ) B . ( 26 N ) ( mathbf{c} cdot 29 N ) D. 45.9 N |
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102 | If positively charged pendulum is oscillating in a uniform electric field as shown in figure. Its time period as compared to that when it was uncharged: A. will increase B. will decreas c. will not change D. will first increase then decreas |
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103 | An infinite number of charges, each of charge ( 1 mu C ) are placed on the ( x ) -axis with co-ordinates ( x=1,2,4,8, dots dots dots ) an charge of ( 1 mathrm{C} ) is kept at the origin, then what is the net force acting on ( 1 mathrm{C} ) charge A. 9000 N B. 12000 N c. ( 24000 mathrm{N} ) D. 36000 N |
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104 | An electric dipole is placed near a positive charge. It will experience: A. a torque only B. a force only c. both torque and force D. it will depend on the orientation of the dipole with respect to the charge |
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105 | If a glass rod is rubbed on silk cloth and then brought near the bits of paper it….. then A. Attracts B. Repel c. Both D. None |
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106 | If the intensity of electric field at a distance ( x ) from the centre in axial position of small electric dipole is equal to the intensity at a distance ( y ) in equatorial position, then ( mathbf{A} cdot x=y ) в. ( x=y / 2 ) C ( . y=x / 2^{2 / 3} ) D. ( y=x / 2^{1 / 3} ) |
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107 | A particle having charge ( q ) and mass ( m ) is projected with velocity ( overrightarrow{boldsymbol{v}}=2 hat{mathbf{i}}-mathbf{3} hat{mathbf{j}} ) in a uniform electric field ( overrightarrow{boldsymbol{E}}=boldsymbol{E}_{0} cdot hat{boldsymbol{j}} ) Change in momentum ( |Delta bar{p}| ) during any time interval ( t ) is given by: A ( cdot sqrt{q E_{0} t} ) в. ( q E_{0} ) c. ( frac{q E_{0} t}{m} ) D. zero |
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108 | Electric force ( quad ) on the nature of the medium between the charges. A. depends B. does not depend c. sometimes depends D. None of these |
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109 | Three positive charge each of magnitude ( Q ) are placed at the corner of the equilateral tringle. The value of charges placed at the centroid of the triangle such that system must be in equilibrium is ( ^{A} cdot frac{+Q}{sqrt{3}} ) в. ( frac{-Q}{sqrt{3}} ) c. ( frac{-2 Q}{sqrt{3}} ) D. ( frac{+2 Q}{sqrt{3}} ) |
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110 | Explain the principle of a device that can build up high voltage of the order of few million volts
Draw a schematic diagram and explain the working of this device Is there any restriction on the upper |
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111 | Figure shows a closed surface which intersects a conducting sphere. If a positive charge is placed at point ( P ), find the sign of flux passing through the curved surface S. | 12 |

112 | In case of conductors and insulators, if an electric field is applied then conduction current density ( (vec{J}) ) is: This question has multiple correct options A. in the direction of electron flow B. in the direction of proton flow. c. in the direction of electric field D. against the direction of electric field |
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113 | Differentiate between conductors and insulators (any two points). |
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114 | The electric field in the region ( r<a ) is ( boldsymbol{E}=frac{boldsymbol{Y} boldsymbol{Q} boldsymbol{r}}{boldsymbol{a}^{3}} . ) Find ( boldsymbol{Y} ? ) |
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115 | Gaussian surface obtains a measure of the electric charge within the surface A. depending how that internal charge is configured. B. no matter how that internal charge is configured. C. and may sometimes depend how that internal charge is configured D. None of these |
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116 | The potential at a distance R/2 from the centre of a conducting sphere will be:- A. 0 В. ( frac{Q}{8 pi epsilon_{E} R} ) c. ( frac{Q}{4 pi epsilon_{c} R} ) D. none of these |
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117 | Coulomb of charge contains ( overline{mathbf{2 5}} ) electrons ( mathbf{A} cdot 10^{15} ) В. ( 10^{18} ) ( c cdot 10^{20} ) D. None of these |
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118 | If we rotate the dipole of moment ( p ) placed in an electric field ( boldsymbol{E} ) from an ( boldsymbol{theta}_{mathbf{1}} ) to ( theta_{2} ), the work done by the external force is A ( cdot p Eleft(cos theta_{2}-cos theta_{1}right) ) B . ( p Eleft(cos theta_{1}-cos theta_{2}right) ) c. ( p Eleft(sin theta_{2}-sin theta_{1}right) ) D・ ( p Eleft(sin theta_{1}-sin theta_{2}right) ) |
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119 | Which of the following is not a property of electric lines of force? A. Lines of force start from positive charge and terminate at negative charge B. Lines of force always intersect c. The tangent to a line of force at any point gives the direction of the electric field(E) at that point D. The number of lines per unit area, through a plane at right angles to the lines, is proportional to the magnitude of elctric field(E) |
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120 | In the basic ( C s C l ) crystal structure, ( C s^{+} ) and ( C l^{-} ) ions are arranged in a bcc configuration as shown in the figure. The net electrostatic force exerted by the eight ( C s^{+} ) ions on the ( C l^{-} ) ion is : ( ^{A} cdot frac{1}{4 pi varepsilon_{0}} frac{4 e^{2}}{3 a^{2}} ) B. ( frac{1}{4 pi varepsilon_{0}} frac{16 e^{2}}{3 a^{2}} ) c. ( 1 frac{32 e^{2}}{3 a^{2}} ) ( D ) |
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121 | Assertion Heart can be assumed as electric dipole. Reason Its ELOF are just same like a normal dipole. A. Both Assertion and Reason are correct and Reason is the correct explanation for Assertion B. Both Assertion and Reason are correct but Reason is not the correct explanation for Assertion C. Assertion is correct but Reason is incorrect D. Both Assertion and Reason are incorrect |
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122 | Consider a uniformly charged sphere that has a total charge of ( Q ) that has a radius of ( R ). What is the electrostatic potential difference, ( Delta V ), between the centre of the sphere and the surface of the sphere? A ( cdot frac{4 k_{e} q}{R} ) в. ( frac{2 k_{e} q}{R} ) c. ( frac{k_{e} q}{R} ) D. ( frac{k_{e q}}{2 R_{q}} ) |
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123 | Positive and negative point charges of equal magnitude are kept at ( left(0,0, frac{a}{2}right) ) and ( left(0,0, frac{-a}{2}right) ) respectively. The work done by the electric field when another positive point charge is moved from ( (-a, 0,0) ) to ( (0, a, 0) ) is A. Positive B. Negative c. zero D. Depends on the path connecting the initial and final positions |
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124 | In a charged spherical conductor id radius ( 10 mathrm{cm} ) has potential ( V ) at point distant ( 5 c m ) from its center, then the potential at a point ( 15 mathrm{cm} ) away from the center will be then A. ( 3 V ) в. ( frac{3}{2} V ) c. ( frac{2}{3} V ) D. ( frac{1}{3} v ) |
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125 | Find the magnitude of charge appearing on each piece | 12 |

126 | Electric field lines are shown in Fig. State whether the electric potential is greater at A or B. |
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127 | A molecule has a permanent electric dipole moment of ( 5 times 10^{-30} C-m ). If it is supposed to arise from net charge of ( +e ) and ( -e ) in the two regions of the molecule, what is their separation? |
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128 | A system consists of a uniformly charged sphere of radius ( boldsymbol{R} ) and ( mathbf{a} ) surrounding medium filled by a charge with the volume density ( rho=frac{alpha}{r}, ) where ( alpha ) is a positive constant and ( r ) is the distance from the centre of the sphere. Find the charge of the sphere for which the electric field intensity ( boldsymbol{E} ) outside the sphere is independent of ( boldsymbol{R} ) ( ^{mathrm{A}} cdot frac{alpha}{2 varepsilon_{0}} ) в. ( frac{2}{alpha varepsilon_{0}} ) ( c cdot 2 pi alpha R^{2} ) D. None of these |
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129 | Assertion Gaussian surface is considered carefully. Reason The point where electric field to be calculated should be within the surface. A. Both Assertion and Reason are correct and Reason is the correct explanation for Assertion. B. Both Assertion and Reason are correct but Reason is not the correct explanation for Assertion. C. Assertion is correct but Reason is incorrect. D. Both Assertion and Reason are incorrect. |
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130 | If a charge ( -150 n C ) is given to a concentric spherical shell and a charge ( +50 n C ) is placed at its centre, then the charge on inner and outer surface of the shell is A. ( 50 n C, 100 n C ) в. ( -50 n C,-100 n C ) c. ( 50 n C, 200 n C ) D. ( -50 n C,-200 n C ) |
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131 | Out of two copper spheres of the same size, ( x ) is hollow while ( y ) is solid. If they are charged at the same potential, what can be said about the charges on them? A. Charge on both the spheres is zero B. Charge on both the spheres is equal c. sphere ( y ) will have more charge D. sphere ( x ) will have more charge |
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132 | Calculate the electric potential at point ( R ) on the ( x- ) axis A . 0 B. ( V=frac{q}{4 pi epsilon_{o} sqrt{a^{2}+y^{2}}} ) c. ( V=frac{q}{4 pi epsilon_{o}}left(frac{1}{x+a}-frac{1}{x-a}right) ) ( V=frac{q}{4 pi epsilon_{o}}left(frac{1}{x+a}+frac{1}{x-a}right) ) |
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133 | Coulomb’s law for electrostatic force between two point charges and Newton’s law for gravitational force between two stationary point masses, both have inverse-square dependence on the distance between the charges/masses. (a) Compare the strength of these forces by determining the ratio of their magnitudes (i) for an electron and a proton and (ii) for two protons. (b) Estimate the accelerations of electron and proton due to the electrical force of their mutual attraction when they are ( 1 A ) ( left.mathbf{1 0}^{-mathbf{1 0}} boldsymbol{m}right) ) apart? ( left(boldsymbol{m}_{boldsymbol{p}}=mathbf{1 . 6 7} timesright. ) ( left.mathbf{1 0}^{-mathbf{2 7}} mathbf{k g}, boldsymbol{m}_{e}=mathbf{9 . 1 1} times mathbf{1 0}^{-mathbf{3 1}} mathbf{k g}right) ) |
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134 | A body has a charge of one coulomb. The number of excess (or lesser) electrons on it from its normal state will be : ( A cdot infty ) B . ( 1.6 times 10^{-19} ) ( mathbf{c} cdot 1.6 times 10^{19} ) D. ( 6.25 times 10^{18} ) |
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135 | Charge 1 attracts Charge ( 2, ) Charge 2 repels Charge ( 3, ) and Charge 3 attracts Charge 4. Which of the following option must hold good for the given condition of four point charges? A. Charge 1 attracts Charge 4 B. Charge 2 attracts Charge 3 c. charge 1 repels Charge 3 D. charge 2 repels Charge 4 E. charge 1 repels charge 4 |
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136 | A flat square sheet of charge (side 50 ( mathrm{cm} ) carries a uniform surface charge density. An electron 0.5 cm from a point near the center of the sheet experiences a force of ( 1.8 times 10^{-12} N ) directed away from the sheet. Determine the total charge on the sheet |
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137 | Find the electric field in the region labelled 3 ( A cdot 0 ) B ( cdot k_{e} frac{q}{r^{2}} ) ( c cdot 2 k_{e} frac{q}{r^{2}} ) ( mathrm{D} cdot 3 k_{e} frac{q}{r^{2}} ) |
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138 | Electric field produced due to an infinitely long straight uniformly charged wire at perpendicular distance of ( 2 c m ) is ( 3 times 10^{8} N C^{-1} ). Then, linear charge density on the wire is ( left(K=9 times 10^{9} S I quad text { unit }right) ) A ( cdot 3.33 frac{mu C}{m} ) в. ( 333 frac{mu C}{m} ) c. ( quad 666 frac{mu C}{m} ) D. ( 6.66 frac{mu C}{m} ) |
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139 | The magnetic flux through a coil perpendicular to the plane is varying according to the relation ( varphi= ) ( left(5 t^{3}+4 t^{2}+2 t-5right) ) wb. Calculate the induced current through the coil at ( t= ) 2 sec, if the resistance of the coil is ( 5 Omega ) |
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140 | A point charge q of mass ( mathrm{m} ) is located at the center of a ring having radius ( mathrm{R} ) and charge Q.When it is displaced slightly, the point charge accelerates along the x-axis to infinity, the ultimate speed of the point charge:- A ( cdot sqrt{frac{2 K Q q}{m R}} ) в. ( sqrt{frac{K Q q}{m R}} ) c. ( sqrt{frac{K Q q}{2 m R}} ) D. zero |
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141 | Charging by friction is used to develop charges on A. metals B. conductors c. insulators D. Non of these |
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142 | Udxidı Canıt ILyplicaliy ustu IUI CdNIE and satellite tv) has its signal run on a copper wire surrounded by an insulator which is surrounded by the ground wire, as opposed to the typical side by side configuration. What is the most logical reason for this? A. The energy held in the electric field between the inside wire and the outside allow for a clearer signal. B. The outside wire prevents any magnetic field from the inside wire from leaking out of the wire C. The outside wire prevents electric fields from interfering with the signal in the inside wire D. The overall resistance of the wire is reduced using this configuration. |
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143 | Two small blocks of charges ( 5 mu C ) and ( 3 mu C ) are kept on a rough surface ( (mu= ) 0.5) at a separation of 0.1 m. Find the separation between the blocks when they come to rest. A . ( 0.27 mathrm{m} ) в. 0.6 т c. ( 0.72 m ) D. 1.27 m |
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144 | Assertion Acceleration of charged particle in nonuniform electric field does not depend on velocity of charge particle. Reason Charge is an invariant quantity. That is amount of charge on particle does not depend on frame of reference. A. Both Assertion and Reason are correct and Reason is the correct explanation for Assertion B. Both Assertion and Reason are correct but Reason is not the correct explanation for Assertion c. Assertion is correct but Reason is incorrect D. Both Assertion and Reason are incorrect |
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145 | ( n ) charged drops, each of radius ( r ) and charge ( q, ) coalesce to form a big drop of radius ( R ) and charge ( Q . ) If ( V ) is the electric potential and ( boldsymbol{E} ) is the electric field at the surface of a drop, then : A ( cdot E_{text {big}}=n^{2 / 3} E_{text {small}} ) B. ( V_{text {big}}=n^{1 / 3} V_{text {small}} ) C. ( E_{text {small}}=n^{2 / 3} E_{text {big}} ) D. ( V_{text {big}}=n^{2 / 3} V_{text {small}} ) |
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146 | Two equations are given below: A) ( oint overline{boldsymbol{E}} cdot boldsymbol{d} overline{boldsymbol{A}}=frac{boldsymbol{Q}}{boldsymbol{E}_{0}} ) B) ( oint overline{boldsymbol{B}} cdot boldsymbol{d} overline{boldsymbol{A}}=mathbf{0} ) A. A – Ampere’s law B – Gauss law for electricity B. A – Gauss law for electric fields B – Gauss law for magnetic fields C . A – Faraday law B-Gauss law for electric fields D. Both (A) and (B) represent Faraday law |
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147 | Show that the equilibrium is unstable. | 12 |

148 | A positively charged ball hangs from a silk thread. We put a positive test charge ( q_{0} ) at a point and measure ( F / q_{0} ) then it can be predicted that the electric field strength E. ( A cdot>F / q_{0} ) в. ( =F / q ) c. ( <F / q_{0} ) D. Cannot be estimated |
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149 | A soild sphere of radius ( boldsymbol{R}_{1} ) and volume charge density ( rho=frac{rho_{0} o}{r} ) is enclosed by a hollow sphere of radius ( R_{2} ) with negative surface charge density ( sigma ), such that the total charge in the system is zero. ( rho_{0} ) is a positive constant and ( r ) is the distance from the center of the sphere.Then the ratio ( boldsymbol{R}_{2} / boldsymbol{R}_{1} ) is ( A cdot sigma / rho_{o} ) B. ( sqrt{2 sigma} / rho_{o} ) c. ( sqrt{rho_{-} o} / quad 2 sigma ) D. ( rho_{o} / sigma ) |
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150 | Three charger ( q . Q ) and ( 4 q ) are placed in a straight, line of length ( L ) at points distant ( 0, L / 2 ) and ( L ) respectively from one end in other to make the net force on ( q ) zero the charge ( Q ) must be eqyal to: A. ( -q ) в. ( 2 q ) c. ( -frac{q}{2} ) D. ( q ) |
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151 | A gold leaf electroscope can be used to: A. detect the presence of charge only B. test the kind of charge only C. measure the charge only D. detect the presence of charge and test the kind of charge |
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152 | The angle between electric dipole moment ( P ) and the electric field ( E ) when the dipole is in stable equilibrium is A . 0 B. ( frac{pi}{4} ) ( c cdot frac{pi}{2} ) D. ( pi ) |
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153 | (a) Write Gauss’ law for magnetism in the form of Maxwell’s equation. (b) Write the value of ( frac{1}{sqrt{mu_{0} varepsilon_{0}}} ) |
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154 | toppr Q Type your question_ the force acting on particle ( A ? ) ( mathbf{A} ) ( B ) ( mathbf{C} ) D. ( E ) |
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155 | An imbalance of electric charges within or on the surface of a material is A. current electricity B. an electromagnetic wave c. static electricity D. None of these |
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156 | An electroscope has a charged rod brought near it, but not touching, and the leaves open, Fig.I. Then a ground wire is attached to the electroscope and the leaves close, Fig. II. Finally, the ground wire and then the rod are removed. It is determined that the electroscope leaves have a net positive charge. Determine the charge of the rod and leaves in Fig. 1: A. The rod has a net positive charge while the leaves have net negative charge B. The rod has a net negative charge while the leaves have a net positive charge c. Both have a negative charge D. It is impossible to determine with the given information |
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157 | Two electric lines of force never intersect. A . True B. False |
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158 | State whether given statement is True or False
Innermost electrons are free to move: |
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159 | Two point charges ( q_{1} ) and ( q_{2} ) are fixed at position vectors ( 4 hat{i} ) and ( 3 hat{j} ) respectively. If a third charge ( q_{3} ) is in electrostatic equilibrium, then the position vector of ( q_{3} ) may be : This question has multiple correct options A . ( 2 hat{i}+1.5 hat{j} ) B . ( -2 hat{i}+4.5 hat{j} ) c. ( 4 hat{i}+3 hat{j} ) D. ( 3 hat{i}+4 hat{j} ) |
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160 | If the dipole is place in a non-uniform electric field an angle ( theta, ) in addition tarque A. Experiences a force B. Experiences a repulsive force c. No any kind of force D. Neither attractive nor repulsive force |
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161 | An ebonite rod held in hand can be charged by rubbing with flannel but a copper rod cannot be charged like this. Why? |
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162 | Charge ( Q, 2 Q ) and ( 4 Q ) are uniformly distributed in three dielectric solid spheres 1,2 and 3 of ( operatorname{radii} R / 2, R ) and ( 2 R ) respectively, as shown in figure. If magnitudes of the electric field at point ( P ) at a distance ( R ) from the centre of spheres 1,2 and 3 are ( E_{1}, E_{2} ) and ( E_{3} ) respectively, then ( mathbf{A} cdot E_{1}>E_{2}>E_{3} ) B ( cdot E_{3}>E_{1}>E_{2} ) ( mathbf{c} cdot E_{2}>E_{1}>E_{3} ) ( mathbf{D} cdot E_{3}>E_{2}>E_{1} ) |
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163 | A tube of length L is filled completely with an incompressible liquid of mass M and closed at both the ends. The tube is then rotated in a horizontal plane about one of its ends with a uniform angular velocity ( omega . ) The force exerted by the liquid at the other ends is:- A ( cdot frac{M L omega^{2}}{2} ) B. ( frac{M L^{2} omega}{2} ) c. ( M L omega^{2} ) D. ( frac{M L^{2} omega^{2}}{2} ) |
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164 | A work of ( 200 J ) is done in moving a charge of ( -5 C ) from infinity to a particular point in an electrostatic field The potential of this point is……….. ( mathbf{A} cdot-20 V ) в. ( -25 V ) c. ( -30 V ) D. ( -40 V ) |
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165 | If ( vec{E}=3 hat{i}+4 hat{j}-5 hat{k}, ) calculate the electric flux through a surface of area 50 units in z-x plane |
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166 | A charge ( q ) is to be distributed on two conducting spheres. What should be the value of the charges on the spheres so that the repulsive force between them is maximum when they are placed at a fixed distance from each other in air? A ( cdot frac{q}{2} ) and ( frac{q}{2} ) в. ( frac{q}{4} ) and ( frac{3 q}{4} ) c. ( frac{q}{3} ) and ( frac{2 q}{3} ) D. ( frac{q}{5} ) and ( frac{4 q}{5} ) |
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167 | Two copper spheres of the same radii, one hollow and the other solid, are charged to the same potential, then A. hollow sphere holds more charge B. solid sphere holds more charge c. both hold equal charge D. we cant say |
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168 | Two infinitely large sheets having charge densities ( sigma_{1} ) and ( sigma_{2} ) respectively ( left(sigma_{1}>sigma_{2}right) ) are placed near each other separated by distance ( d . A ) charge ( q ) is placed in between two plates such that there is no effect on charge distribution on plates. Now this charge is moved at an angle of ( 45^{circ} ) with the horizontal towards plate having charge density ( sigma_{2} ) by distance ( a(a<d) . ) Find work done by electric field in the process. |
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169 | The dimensional formula for electric flux is A ( cdotleft[M L^{3} I^{-1} T^{-3}right. ) B ( cdotleft[M^{2} L^{2} I^{-1} T^{-2}right] ) C . ( left[M L^{3} I^{1} T^{-3}right] ) ( mathbf{D} cdotleft[M L^{-3} I^{-1} T^{-3}right] ) |
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170 | A spherical conducting shell of inner radius ( r_{1} ) and outer radius ( r_{2} ) has a charge ( Q . A ) charge ( -q ) is placed at the center of the shell. The surface of the shell will be A ( cdot frac{q}{4 pi r_{1}^{2}} ) and ( frac{Q}{4 pi r_{2}^{2}} ) В. ( frac{-q}{4 pi r_{1}^{2}} ) and ( frac{Q+q}{4 pi r_{2}^{2}} ) c. ( frac{q}{4 pi r_{1}^{2}} ) and ( frac{Q-q}{4 pi r_{2}^{2}} ) D. 0 and |
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171 | The electric field strength produced at a point some distance away from a source charge does NOT depend on: A. The magnitude of the source charge B. The sign of the source charge c. The distance from the source charge D. The nature of the medium surrounding the source charge E. None of the above |
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172 | The process due to which an uncharged body acquires electric charges when held near a charged body is called: A. conduction B. induction c. convection D. none of these |
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173 | A sample of HCl gas is placed in an electric field of ( 2.5 times 10^{4} N C^{-1} ). The dipole moment of each HCl molecule is ( 3.4 times 10^{-30} mathrm{Cm} . ) Find the maximum torque that can act on a molecule. |
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174 | Give three properties of electric charge. | 12 |

175 | ( Q ) amount of electric charge is present on the surface of a sphere having radius ( boldsymbol{R} ). Then electrical potential energy of this system is ( mathbf{A} cdot frac{K Q^{2}}{R^{2}} ) в. ( frac{K Q^{2}}{R} ) c. ( frac{1}{2} frac{K Q^{2}}{R} ) D. ( frac{1}{2} frac{K Q^{2}}{R^{2}} ) |
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176 | Examples of non-conductors include A. sulphur B. phosphorus. c. wood D. all of these. |
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177 | State whether true or false. Ebonite is a good conductor of electricity. A. True B. False |
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178 | A gold leaf electroscope is given a positive charge so that its leaves diverge. How is the divergence of leaves affected, when a negatively charged rod is brought near its disc? A. divergence increases B. divergence decreases c. divergence remains same D. can’t say |
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179 | A metal sphere of radius ( 1 mathrm{cm} ) is given a charge of ( 3.14 mu C . ) Find the electric intensity at a point ( 1 mathrm{m} ) from the center of the sphere. |
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180 | The coulombic force of attraction between two charges increases with increase in the distance of separation between them. A. True B. False |
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181 | A charge ( q ) is moving with a velocity ( bar{v}_{1}= ) 1 ìm / ( s ) at a point in a magnetic field and experiences a force ( overline{boldsymbol{F}}_{mathbf{1}}=boldsymbol{q}[-mathbf{1} hat{boldsymbol{j}}+ ) ( mathbf{1} hat{boldsymbol{k}}] boldsymbol{N} . ) If the charge is moving with a velocity ( bar{v}_{2}=1 hat{j} m / s ) at the same point it experiences a force ( overline{boldsymbol{F}}_{2}=boldsymbol{q}[mathbf{1} hat{boldsymbol{i}}-mathbf{1} hat{boldsymbol{k}}] boldsymbol{N} ) The magnetic induction ( bar{B} ) at that point is ( mathbf{A} cdot(hat{i}+hat{j}+hat{k}) W b / m^{2} ) B ( cdot(hat{i}-hat{j}+hat{k}) W b / m^{2} ) ( mathbf{c} cdot(-hat{i}+hat{j}-hat{k}) W b / m^{2} ) D. ( (hat{i}+hat{j}-hat{k}) W b / m^{2} ) |
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182 | The electric field in a region is radially outwards and has a magnitude ( boldsymbol{E}=boldsymbol{K} boldsymbol{r} ) The charge contained in a sphere of radius ( a ) is : A. ( K 4 pi varepsilon_{0} a^{2} ) В ( cdot quad K frac{4}{3} pi varepsilon_{0} a^{3} ) c. ( K 4 pi varepsilon_{0} a^{3} ) D. none of these |
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183 | Two conducting spheres of radii ( r_{1} ) and ( r_{2} ) are charged such that they have the same electric field on their surfaces. The ratio of the electric potential at their centres is : A. ( sqrt{frac{r_{1}}{r_{2}}} ) в. ( frac{r_{1}}{r_{2}} ) c. ( frac{r_{1}^{2}}{r_{2}^{2}} ) D. none of the above |
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184 | The constant ( k ) in Coulomb’s law depends upon A. nature of medium B. system of units c. intensity of charge D. both (a) and (b) |
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185 | An electric dipole is placed at the origin and is directed along the ( x ) -axis. At a point ( P, ) far away from the dipole,the electric field is parallel to the y-axis. OP makes an angle ( theta ) with the ( x ) -axis. Then, A ( cdot tan theta=sqrt{3} ) B. ( tan theta=sqrt{2} ) ( mathbf{c} cdot tan theta=1 ) D. ( tan theta=frac{1}{sqrt{2}} ) |
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186 | Two infinitely long parallel conducting plates having surface charge densities ( +sigma ) and ( -sigma ) respectively, are separated by a small distance. The medium between the plates is vacuum. If ( varepsilon_{0} ) is the dielectric permittivity of vacuum then the electric field in the region between the plates is: A. 0 volt ( / m ) в. ( sigma / 2 varepsilon_{0} ) volt ( / mathrm{m} ) c. ( sigma / varepsilon_{0} ) volt ( / mathrm{m} ) D. ( 2 sigma / varepsilon_{0} ) volt ( / mathrm{m} ) |
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187 | The electric potential due to a small electric dipole at a large distance ( r ) from the centre of the dipole is proportional to : ( A ) B. 1 / c. ( 1 / r^{2} ) D. ( 1 / r^{3} ) |
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188 | The electric flux emerging through the closed surface ( S_{1} ) shown in figure which intersects the spherical conductor ( boldsymbol{S} ) due to the presence of a positive charge very near to conductor is: A. Positive B. Negative c. zero D. None of the above |
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189 | The test charge used to measure electric field at a point should be A. infinitely large B. vanishingly small c. negative D. zero |
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190 | A small conducting sphere of radius ( r ) is Iying concentrically with a bigger hollow conducting sphere of radius ( boldsymbol{R} ) The bigger and smaller spheres are charged with ( Q ) and ( q ) respectively ( (Q>q) . ) The two spheres are insulated from one another. The potential difference between the spheres will be : A ( cdot frac{1}{4 pi epsilon_{0}}left(frac{q}{r}-frac{Q}{R}right) ) В. ( frac{1}{4 pi epsilon_{0}}left(frac{q}{r}-frac{q}{R}right) ) ( ^{mathbf{C}} cdot frac{1}{4 pi epsilon_{0}}left(frac{q}{r}+frac{Q}{R}right) ) D. ( frac{1}{4 pi epsilon_{0}}left(frac{q}{R}-frac{Q}{r}right) ) |
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191 | A dipole of dipole moment ‘p’ is placed in non-uniform electric field along ( x ) axis. Electric field is increasing at the rate of ( 1 ~ V m^{-1} . ) The force on dipole is: ( mathbf{A} cdot mathbf{0} ) в. ( 2 p ) c. ( p / 2 ) D. |
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192 | As shown in fig. if a charge ( +q ) is carried from a point ( boldsymbol{A}left(boldsymbol{r}, mathbf{1} mathbf{3 5}^{circ}right) ) to point ( Bleft(r, 45^{circ}right) . ) If dipole moment is ( p ) then the work done by the external agent is then going to be A . 0 В. ( frac{q p}{4 pi epsilon_{0} r^{2}} ) ( c cdot frac{1}{4 pi epsilon_{0}} frac{sqrt{2} q p}{r^{2}} ) D. ( frac{1}{4 pi epsilon} frac{q p}{r^{2}} ) |
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193 | A body has a total charge of ( 6.4 times 10^{-19} ) coulomb. It is : A. possible B. not possible c. may or may not be possible D. Data insufficient |
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194 | An inclined plane of length ( 5.60 m ) making an angle of ( 45^{circ} ) with the horizontal is placed in an uniform electric field ( boldsymbol{E}=mathbf{1 0 0} boldsymbol{V m}^{-1} . ) A particle of mass ( 1 k g ) and charge ( 10^{-2} C ) is allowed to slide down from rest position from maximum height of slope. If the coefficient of friction is ( 0.1, ) the time taken by the particle to reach the bottom is ( mathbf{A} cdot 1 s ) B. ( 1.41 s ) c. ( 2 s ) D. None of these |
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195 | Compute the electric flux through a square surface of edges ( 2 l ) due to a charge ( +Q ) whose geometric centre is located on the ( x ) -axis at a perpendicular distance ( l ) from the centre of the square. A ( cdot frac{Q}{epsilon_{0}} ) в. ( frac{Q}{2 epsilon_{0}} ) c. ( frac{Q}{4 epsilon_{0}} ) D. ( frac{Q}{6 epsilon_{0}} ) |
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196 | Electric field intensity at points in between and outside two thin separated parallel sheets of infinite dimension with like charges of same surface charge density ( (sigma) ) are and respectively A ( cdot sigma / epsilon_{0}, sigma / epsilon_{0} ) в. ( 0, sigma / epsilon_{0} ) ( c .0,0 ) D. ( sigma / varepsilon_{0}, 0 ) |
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197 | A hemispherical body is placed in a uniform electric field E. What is the flux linked with the curved surface if the field is perpendicular to the curved surface at every points as in figure. A ( cdot phi=E 4 pi R^{2} ) В. ( phi=E 2 pi R^{2} ) c. ( phi=E 7 pi R^{2} ) D. ( phi=E 9 pi R^{2} ) |
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198 | A dipole consisting of ( +10 n C ) and ( -10 n C ) separated by a distance of ( 2 mathrm{cm} ) oscillates in an electric filed of strength ( 60,000 mathrm{Vm}^{-1} . ) The frequency of its oscillation is (Moment of inertia about the axis of oscillations is ( 3 times 10^{-10} mathrm{kgm}^{2} ) ): A . ( 20.2 mathrm{Hz} ) в. ( 25.4 mathrm{Hz} ) c. ( 31.38 H z ) D. ( 37.1 mathrm{Hz} ) |
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199 | Two points ( A ) and ( B ) are located at distance of ( 100 mathrm{cm} ) from on electric dipole. A is sn axial point while B is in perpendicular bisector. The electric field intensity at ( A ) is ( vec{E} ). Then the intensity at B will be ( A cdot vec{E} ) в. ( 2 vec{E} ) ( c cdot-vec{E} ) D. ( -frac{vec{E}}{2} ) |
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200 | 000 灣 8 What |
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201 | The electric field of a plane polarized electromagnetic Wave in free space at time ( t=0 ) i given by an expression ( overrightarrow{boldsymbol{E}}(boldsymbol{x}, boldsymbol{y})=10 hat{j} cos [(boldsymbol{6} boldsymbol{x}+boldsymbol{8} boldsymbol{z})] ) The magenetic field ( vec{B}(x, z, t) ) is given by ; (c is the velocity of light will be: A ( cdot frac{1}{c}(4 hat{k}+8 hat{i}) cos [(2 x-8 z+20 c t)] ) B ( cdot frac{1}{c}(6 hat{k}-8 hat{i}) cos [(6 x+8 z-10 c t)] ) c. ( frac{1}{c}(5 hat{k}+8 hat{i}) cos [(6 x+8 z-80 c t) ) D ( cdot frac{1}{c}(4 hat{k}-8 hat{i}) cos [(6 x+8 z+70 c t)] ) |
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202 | Electric ield on the axis of small electric dipole at a distance ( r ) is ( vec{E}_{1} ) and ( vec{E}_{2} ) at ( a ) distance ( 2 mathrm{r} ) on a line of perpendicular dissector. Then ( ^{mathbf{A}} cdot vec{E}_{2}=-frac{vec{E}_{1}}{8} ) В ( quad vec{E}_{2}=-frac{vec{E}_{1}}{16} ) ( mathbf{c} cdot underset{E_{2}}{overrightarrow{4}}=-frac{vec{E}_{1}}{_{1}} ) D ( quad vec{E}_{2}=frac{vec{E}_{1}}{8} ) |
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203 | The electric flux over the surface of a sphere if it is charged with ( 10 mu C ) is A ( cdot 36 pi times 10^{4} quad N m^{2} / C ) B . ( 36 pi times 10^{-4} quad N m^{2} / C ) ( begin{array}{ll}text { C. } 36 pi times 10^{6} & text { N } m^{2} / Cend{array} ) D. ( 36 pi times 10^{-6} quad mathrm{Nm}^{2} / mathrm{C} ) |
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204 | A cubical region of side a has its centre at the origin. It encloses three fixed point charges,- -q ( a t(0,-a / 4,0),+3 q ) at (0,0,0) and ( -q ) at ( (0,+a / 4,0) . ) Choose the correct option(s): This question has multiple correct options |
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205 | Find the location of charge on the conducting shell. ( mathbf{A} cdot+2 Q ) on the inner surface at ( r=a, Q ) on the outer surface of the conductor at ( r=b ) B. ( -2 Q ) on the inner surface at ( r=a, Q ) on the outer surface of the conductor at ( r=b ) C. ( +2 Q ) on the inner surface at ( r=a, 3 Q ) on the outer surface of the conductor at ( r=b ) D. ( -2 Q ) on the inner surface at ( r=a, 3 Q ) on the outer surface of the conductor at ( r=b ) |
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206 | Which of the following is a good conductor of heat? A. steel B. Glass c. wood D. Rubber |
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207 | A charge ( q_{o} ) is distributed uniformly on a ring of radius R. A sphere of equal radius R isconstructed with its centre on the circumference of the ring. Find the electric flux through the surface of the sphere. A ( cdot frac{q_{0}}{3 varepsilon_{0}} ) в. ( frac{q_{0}}{2 varepsilon_{0}} ) c. ( frac{2 q_{0}}{varepsilon_{0}} ) D. ( frac{4 q_{0}}{3 varepsilon_{0}} ) |
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208 | State and explain coulomb’s inverse square law |
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209 | The force of attraction between two charges ( 8 mu C ) and ( 0.2 N . ) Find the distance of separation. A. 412 meter B. 1.2 meter c. 120 meter D. 0.12 meter |
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210 | Two concentric, thin metallic spherical shells of radii ( R_{1} ) and ( R_{2}left(R_{1}>R_{2}right) ) bear charges ( Q_{1} ) and ( Q_{2} ) respectively. Then the potential at radius ‘r’ between ( R_{1} ) and ( R_{2} ) will be ( frac{1}{4 pi epsilon_{0}} ) times A ( cdot frac{Q_{1}+Q_{2}}{r} ) В ( cdot frac{Q_{1}}{R_{1}}+frac{Q_{2}}{r} ) c. ( frac{Q_{1}}{R_{1}}+frac{Q_{2}}{R_{2}} ) D. ( frac{Q_{1}}{R_{2}}+frac{Q_{2}}{R_{2}} ) |
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211 | An electric dipole of length ( 20 mathrm{cm} ) having ( pm 3 times 10^{-3} C ) charge placed at ( 60^{circ} ) with respect to a uniform electric field experiences a torque of magnitude ( 6 N m . ) The potential energy of the dipole is A. ( -2 sqrt{3} J ) ( J ) B. ( 5 sqrt{3} J ) c. ( -2 sqrt{2} J ) D. ( 3 sqrt{5} ) |
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212 | State whether true or false: Gauss law is applicable only when there is a symmetric distribution of charge. A. True B. False |
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213 | A single electron has change ( |e|= ) ( mathbf{1 . 6} times mathbf{1 0}^{-19} mathbf{C} . ) If the current passing through a conducting wire is ( 0.32 A ) how many electrons would pass through the wire In one hour? A. ( 7.2 times 10^{20} ) В. ( 7.2 times 10^{21} ) c. ( 7.2 times 10^{19} ) D. ( 2 times 10^{18} ) |
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214 | How many electronic charges form 1 coulomb? A. ( 9.1 times 10^{-31} ) B . ( 1.6 times 10^{18} ) c. ( 62.5 times 10^{17} ) D. ( 1.76 times 10^{11} ) |
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215 | A particle with mass 2.0 mg and charge ( 3.0 mu C ) is in a region with uniform electric field of ( (mathbf{3} hat{boldsymbol{i}}+boldsymbol{4} hat{boldsymbol{j}}) boldsymbol{N} / boldsymbol{C} ). The acceleration of the particle will be: A ( cdot(3 hat{i}+4 hat{j}) m / s^{2} ) B ( cdot(1.5 hat{i}+2 hat{j}) m / s^{2} ) ( mathbf{c} cdot(4.5 hat{i}+6 hat{j}) m / s^{2} ) D. ( (2 hat{i}+3 hat{j}) m / s^{2} ) |
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216 | A point charge ( Q ) is located at the center of the hollow spherical conductor of inner radius ( boldsymbol{R}_{1} ) and outer radius ( boldsymbol{R}_{2} ) the conductor being uncharged initially The potential at the inner surface will be A ( cdot K Qleft[frac{1}{R_{1}}+frac{1}{R_{2}}right] ) В ( cdot K Qleft[frac{1}{R_{1}}-frac{1}{R_{2}}right] ) c. ( K Qleft[frac{1}{R_{2}}-frac{1}{R_{1}}right] ) D. None of these |
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217 | A point charge ( q ) is located at the point ( (0,0,-a) . ) Consider a hemispherical surface of radius ‘a’ with its centre at the origin and ( z geq 0 . ) The modulus of the electric flux through the hemispherical surface is: A ( cdot q / €_{0} ) B ( cdot q /left(2 sqrt{2} in_{0}right) ) ( ^{mathbf{c}} cdotleft(1-frac{1}{sqrt{2}}right) q / epsilon_{0} ) D ( left(1-frac{1}{sqrt{2}}right) q /left(2 in_{0}right) ) |
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218 | Why do insulators take larger time to heat up? A. They need more heat per every degree Celsius rise in temperature B. They need more energy per every degree Celsius rise in temperature C. They need more to perform more work per every degree Celsius rise in temperature. D. They need more heat per every degree Farenheit rise in temperature |
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219 | If a dipole of dipole moment ( vec{p} ) is placed in a uniform electric field ( vec{E} ), then torque acting on it is given by : ( mathbf{A} cdot vec{tau}=vec{p} cdot vec{E} ) В . ( vec{tau}=vec{p} times vec{E} ) C ( cdot vec{tau}=vec{p}+vec{E} ) D . ( vec{tau}=vec{p}-vec{E} ) |
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220 | Infinite charges of magnitude ( q ) each are lying at ( boldsymbol{x}=mathbf{1}, mathbf{2}, mathbf{4}, mathbf{8}, dots dots dots ) metre on X-axis. The value of intensity of electric field at point ( x=0 ) due to these charges will be A ( cdot 12 times 10^{9} q N / C ) в. zero c. ( 6 times 10^{9} q N / C ) D. ( 4 times 10^{9} q N / C ) |
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221 | Two concentric thin metallic spheres of radii ( boldsymbol{R}_{1} ) and ( boldsymbol{R}_{2}left(boldsymbol{R}_{1}>boldsymbol{R}_{2}right) ) bear charges ( Q_{1} ) and ( Q_{2} ) respectively. Then the potential at a radius ( r ) between ( R_{1} ) and ( boldsymbol{R}_{2} ) will be ( 1 / 4left(pi varepsilon_{0}right) ) times: A. ( frac{Q_{1}+Q_{2}}{4} ) в. ( frac{Q_{1}}{R_{1}}+frac{Q_{2}}{r} ) c. ( frac{Q_{1}}{R_{1}}+frac{Q_{2}}{R_{2}} ) D. ( frac{Q_{1}}{R_{2}}+frac{Q_{2}}{R_{1}} ) |
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222 | A conducting sphere is negatively charged. Which of the following statements is true? A. The charge is uniformly distributed throughout the entire volume B. The charge is located at the center of the sphere c. The charge is located at the bottom of the sphere because of gravity D. The charge is uniformly distributed on the surface of the sphere |
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223 | In which position ( (A, B, C, text { or } D) ) of second charge, the flux of the electric field through the hemisphere remains uncharged? Explain. |
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224 | Electrostatic induction is used to charge A. Conductors B. Semiconductors c. Insulators D. All of the above |
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225 | Two positive charges ( boldsymbol{q}_{1}=20 C ) and ( q_{2}=6 C ) are separated by diameter of 3 ( m ). Then what is the force produced by them? ( A cdot 80 N ) B. ( 53.3 N ) ( c .56 N ) D. ( 72.5 N ) |
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226 | Two charged capacitors, have their outer plates fixed and inner plates connected by a spring of force constant ( k^{prime} . ) The charge on each capacitor is ( q ) Find the extension in the spring at equilibrium. ( ^{A} cdot frac{q^{2}}{2 A epsilon_{0} k} ) в. ( frac{q^{2}}{4 A epsilon_{6} k} ) c. ( frac{q^{2}}{A epsilon_{6} k} ) D. Zero |
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227 | Q Type your question unırormiy aıstrıbutea tnrougnout ırs volume Which of the following expressions |
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228 | How many megacoulombs of positive charge are in 1.00 mol of neutral molecular hydrogen ( operatorname{gas}left(boldsymbol{H}_{2}right) ) |
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229 | The electric field in a region of space is given by ( mathrm{E}=5 mathrm{i}+2 mathrm{j} ) N/C. The electric flux due to this field through an area ( 2 m^{2} ) lying in the YZ plane, in S.l unit, is A . 10 B. 20 c. ( 10 sqrt{2} ) D. ( 2 sqrt{29} ) |
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230 | State whether the following statements are True or False. If ( mathrm{E}=0, ) at all points of a closed surface, The electric flux through the surface is zero. A. True B. False |
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231 | An infinitely long cylinder of radius ( mathrm{R}=2 mathrm{cm} ) carries a uniform charge density ( =18 mu mathrm{C} / mathrm{m} 3 ) Calculate the electric field at distance ( r=1 mathrm{cm} ) from the axis of the cylinder. A. The magnitude of electric field intensity at the ( x x ) axis of charged body is ( left(frac{p r^{2}}{2 epsilon_{0} d}right) ) B. The magnitude of electric field intensity at the ( x x ) axis of charged body is zero. C. The magnitude of electric field intensity at the yy axis of charged body is ( left(frac{p d^{2}}{2 epsilon_{0}}right) ) D. The magnitude of electric field intensity at the ( x x ) any point in the cavity is ( frac{p^{2}}{2 epsilon_{0}} d ) |
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232 | The total flux passing through the cube is: ( mathbf{A} cdot(B+C+D) L^{2} ) B . ( 2(B+C+D) L^{2} ) ( mathbf{c} cdot 6(B+C+D) L^{2} ) D. zero |
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233 | A polythene piece rubbed with wool is found to have a negative charge of ( 3 x ) ( mathbf{1 0}^{-mathbf{7}} mathbf{C} ) (a) Estimate the number of electrons transferred (from which to which?) (b) Is there a transfer of mass from wool to polythene? |
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234 | Mud houses are cooler in summer and warmer in winter because A. mud is a good conductor of heat B. mud is a superconductor of heat c. mud is a bad conductor of heat D. none of these |
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235 | A negatively charged particle is situated on a straight line joining two other stationary particles each having charge ( +q . ) The direction of the motion of the negatively charged particle will depend on: A. the magnitude of charge B. the position at which it is situated c. both magnitude of charge and its position. D. the magnitude of ( +q ) |
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236 | Fill in the blanks. A field normal to the plane of a circular wire ( n ) turns and radius r which carries a current I is measured on the axis of the coil at small h distance h from the centre of the coil. This is smaller than the field at the centre by a friction A ( cdot_{3} frac{3 h^{2}}{2 r^{2}} ) B. ( frac{h^{2}}{2 r^{2}} ) c. ( frac{4 h^{2}}{2 r^{2}} ) D. ( frac{3 h^{2}}{2 r^{2}} ) |
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237 | Find the electric field at ( z>0.5 d ) ( mathbf{A} cdot E=0 ) B ( cdot E=-frac{sigma}{epsilon_{0}} hat{k} ) ( mathbf{c} cdot E=frac{sigma}{epsilon_{0}} hat{k} ) D・ ( E=-frac{sigma}{2 epsilon_{n}} hat{k} ) |
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238 | Figure shows a uniformly charged hemisphere of radius R. It has a volume charge density p. If the electric field at point ( 2 R, ) above its center is ( E, ) then what is the electric field at the point ( 2 R ) below its center? ( mathbf{A} cdot rho R / 6 varepsilon_{0}+E ) ( mathbf{B} cdot rho R / 12 varepsilon_{0}-E ) ( mathbf{c} cdot-rho R / 6 varepsilon_{0}+E ) ( mathbf{D} cdot rho R / 12 varepsilon_{0}+E ) |
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239 | The work done to move a charge on an equipotential surface is? A . Infinity B. Less than 1 c. Greater than 1 D. zero |
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240 | If the distance between two equal points charges is doubled and their individual charges are also doubled, what would happen to the force between them? |
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241 | Identify the correct statement: A. Electrostatic forces are much weaker than the gravitational forces. B. Electrostatic forces are much stronger than the gravitational forces. C . Electrostatic forces are comparable to the gravitational forces D. All of the above |
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242 | Calculate the electrostatic force of attraction between a proton and an electron in a hydrogen atom. The radius of the electron orbit is ( 0.05 mathrm{nm} ) and charge on the electron is ( 1.6 times 10^{-9} C ) |
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243 | In the diagram shown, the leaves of the electroscope diverge when a positively charged rod is brought near the knob of an uncharged electroscope. The leaves diverge because: A. They are both negatively charged B. They are both positively charged c. One is positive and one is negative D. One leaf is neutral and one is positive E. Both leaves are neutral |
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244 | What is the direction of the electric field directly south of a positive point charge due to the point charge? A. North B. South ( c . ) East D. west E. Down |
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245 | Mica is a ( _{—} ) conductor of electricity A. good B. badd c. positive D. None of the above |
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246 | When a glass rod is rubbed with a silk cloth, charges appear on both. A similar phenomenon is observed with many other pairs of bodies. Explain how this observation is consistent with the law of conservation of charge. |
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247 | ABCD is a square of 1 metre side of a non-conducting material. Four metallic spheres of 4,5,8 and ( 10 mathrm{cm} ) diameters are placed at the four corners. All of them are connected by a fine metallic wire and charge of 540 units is imparted to the system. The potential at the centre of the square is : (in cgs system) A ( cdot frac{540 sqrt{2}}{400} ) B. ( frac{540 sqrt{2}}{200} ) c. ( frac{540 sqrt{2}}{100} ) D. ( frac{540 sqrt{2}}{10} ) |
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248 | A negatively charged body has A. an excess of protons B. an excess of electrons C . an excess of photons D. an deficiency of electrons |
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249 | Prove that potential at point on transverse (equatorial) position of electric dipole is zero. | 12 |

250 | The force between two short electric dipole placed on the same axis at a distance ( R, ) varies as? ( mathbf{A} cdot R^{-1} ) B. ( R^{-2} ) ( c cdot R^{-3} ) D. ( R^{-4} ) |
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251 | The breakdown electric intensity for air is ( 3 times 10^{6} mathrm{V} / mathrm{m} . ) The maximum charge that can be held by a sphere of radius ( 1 mathrm{mm} ) is A ( .0 .33 C ) в. 0.33 пС ( c .3 .3 C ) D. ( 3.3 mu C ) |
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252 | When a woman with long hair puts her hands on a Van de Graaff Generator large conducting sphere with a conveyor belt delivering charge to it) her hair stands on end. Which of the following best explains this phenomenon? A. Like charges attract B. Like charges repel c. Her hair will not stand on end D. Her body is conducting a current to the ground E. The Van de Graff generator makes a magnetic field that draws her hair up on end |
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253 | An electric dipole of moment ‘p’ is placed in an electric field of intensity ‘E’. The dipole acquires a position such that the axis of the dipole makes an angle ( theta ) with the direction of the field. Assuming that the potential energy of the dipole to be zero when ( =90^{0}, ) the torque and the potential energy of the dipole will respectively be A. ( p E sin theta, p E cos theta ) B. ( p E sin theta,-2 p E cos theta ) c. ( p E sin theta, 2 p E cos theta ) D. ( p E cos theta,-p E cos theta ) |
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254 | The magnitude of electric field intensity E, such electron, placed in the field, would experience an electric force equal to its weight is : A ( cdot 5.6 times 10^{-7} N C^{-1} ) B . ( 5.6 times 10^{-8} N C^{-1} ) c. ( 5.6 times 10^{-10} N C^{-1} ) D. ( 5.6 times 10^{-11} mathrm{NC}^{-1} ) |
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255 | When a glass rod is rubbed with silk cloth, it acquires charge because: A. Electrons are added to it B. Electrons are removed from it c. Protons are added to it D. Protons are removed from it |
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256 | A proton (mass ( 1.67 times 10^{-27} mathrm{kg} ) ) on striking a neutron (mass nearly equal to the proton ) forms a deutron. What would be the velocity of the deutron if it is formed by a proton moving left with a velocity of ( 7.0 times 10^{6} mathrm{m} / mathrm{s} ) and a neutron moving right with a velocity of ( 4.0 times 10^{6} ) ( mathrm{m} / mathrm{s} ) |
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257 | The concept of solid angle is a natural extension of a ( underline{text { angle to }} ) dimensions. ( A ). plane, two B. line, three c. plane, three D. line, two |
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258 | A body of mass ( mathrm{M} ) and charge q is suspended from a string. When slightly displaced, it oscillates with period T. If a uniform electric field acts vertically downwards, then the new time period will be: A ( cdot T^{prime}=T ) в. ( T^{prime}T ) D. cannot be predicted |
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259 | A line formly changed eonducting sphere of ( 24 m ) diameter has a surface change density of ( 80.0 mu c / m^{2} ) (i) Find the charge on the sphere (ii) What is the total electric flux learning the surface of the sphere? A ( cdot 1.447 times 10^{-3} c, 1.63 times 10^{8} frac{N m^{2}}{C} ) В. ( _{2.447} times 10^{-3} c, 1.63 times 10^{8} frac{N m^{2}}{C} ) c. ( _{1.447} times 10^{-3} c, 2.63 times 10^{8} frac{N m^{2}}{C} ) D. ( 41.447 times 10^{-3} c, 1.63 times 10^{8} frac{N m^{2}}{C} ) |
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260 | Point charge ( q_{0} ) is placed inside a cone of base radius ‘R’, x distance below centre of the top surface as shown in figure.Find electric flux related to curved surface of the cone:- A ( cdot frac{q}{2 varepsilon_{0}} ) в. ( frac{q}{varepsilon_{0}}-frac{q}{2 varepsilon_{0}}left(1-frac{x}{sqrt{R^{2}+x^{2}}}right) ) c. ( frac{q}{varepsilon_{0}}left(1-frac{x}{sqrt{R^{2}+x^{2}}}right) ) D. ( frac{q}{varepsilon_{0}} timesleft(frac{x}{sqrt{R^{2}+x^{2}}}right) ) |
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261 | An electron at rest gives rise to only A. Magnetic field B. Electric field C. Both electric and magnetic field D. Neither electric field nor magnetic field |
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262 | spheres of radii ‘a’ and ‘b’, respectively(see figure), has volume charge density ( rho=frac{A}{r}, ) where ( A ) is a constant and ( r ) is the distance from the centre. At the centre of the spheres is a point charge ( Q . ) The value of ( A ) such that the electric field in the region between the spheres will be constant, is : A ( cdot frac{Q}{2 pi a^{2}} ) В. ( frac{Q}{2 pileft(b^{2}-a^{2}right)} ) c. ( frac{2 Q}{pileft(a^{2}-b^{2}right)} ) ( D cdot frac{2 Q}{pi^{2}} ) |
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263 | A circle, having radius “r” has line charge distribution over its circumference having linear charge density ( lambda=lambda_{0} cos ^{2} theta . ) Calculate the total electric charge residing on the circumference of the circle. ( left[int_{0}^{2 pi} cos ^{2} theta d theta=piright] ) |
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264 | Four charges are rigidly along the Y axis as shown. A positive charge approaches the system along the X axis with initial speed just enough to cross the origin. Then its total energy at the origin is A. zero B. positive C . negative D. data insufficient |
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265 | If ( g_{E} ) and ( g_{M} ) are the accelerations due to gravity on the surfaces of the Earth and the Moon respectively and if Millikan’s oil drop experiment could be performed on the two surfaces, one will find the ratio (electronic charge on the Moon/ electronic charge on the Earth) to be: A . 1 B. ( mathbf{c} cdot g_{E} / g_{M} ) D. ( g_{M} / g_{E} ) |
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266 | A small electric dipole is placed at origin with its axis being directed along the positive x-axis. The direction of electric field due to the dipole at a point ( (1 mathrm{m}, sqrt{2} mathrm{m}, 0) ) is along the: A . z-axis B. y-axis c. x-axis D. line ( y=x ) |
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267 | An infinitely long wire is kept along z- axis from ( z=-infty ) to ( z=+infty, ) having uniform linear charge density ( frac{10}{9} n C / m . ) The electric field ( vec{E} ) at point ( (6 mathrm{cm}, 8 mathrm{cm}, 10 mathrm{cm}) ) will be: ( A cdot(160 i+120 j+200 k) N / C ) B. (200 k) N/C ( c cdot(160 i+120 j) N / c ) D. ( (120 mathrm{i}+160 mathrm{j}) mathrm{N} / mathrm{C} ) |
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268 | Cups are not made of metals. The reason is: A. Metals are good conductors B. Metals are bad conductors c. Metals are expensive D. None of the above |
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269 | Select the odd one out w.r.t. conduction of heat (gold, silver, copper, asbestos) A . asbestos B. gold c. silver D. copper |
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270 | Eight dipoles of charges of magnitude ( q ) are placed inside a cube. Then, the total electric flux coming out of the cube will be A ( cdot frac{8 q}{epsilon} ) в. ( frac{16 q}{epsilon} ) c. ( underline{q} ) D. |
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271 | Find the electric field both inside the shell at a distance ( r ) from the centre. ( ^{A} cdot frac{Q}{4 pi epsilon_{0} a^{2}} ) в. ( frac{Q r}{4 pi epsilon_{0} a^{2}} ) c. ( frac{Q}{4 pi epsilon_{0} a^{3}} ) D. ( frac{Q r}{4 pi epsilon_{0} a^{3}} ) |
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272 | Inspite of mutual repulsion between the protons and no electric force between neutrons, a number of protons and neutrons do stay together to form stable nuclei. Which of the following are reasons for this? 1. Another type of force, called nuclear force works between these particles when they are very close to each other 2. The neutrons keep the protons apart so that there is no repulsion between them 3. The nuclear force is always attractive and does not depend on the charge of the particles Select the correct answer from the codes given. ( A cdot 2 ) and 3 only B. 1 and 2 only c. 1,2 and 3 D. 1 and 3 only |
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273 | What is the angle between the electric dipole moment and the electric field due to it on the axial line? A ( cdot 0^{circ} ) B. ( 90^{circ} ) ( c cdot 180^{circ} ) D. none of these |
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274 | Two identical charged spheres suspended from a common point by two massless strings of length I are initially a distance ( d(d<<I) ) apart because of their mutual repulsion. The charge begins to leak from both the spheres at a constant rate. As a result the charges approach each other with a velocity v. Then as a function of distance ( x ) between them A ( . v propto x^{-1 / 2} ) B. ( v propto x^{-1} ) ( mathbf{C} cdot v propto x^{1 / 2} ) D. ( v propto x ) |
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275 | Choose the correct statement. A. Polar molecules have permanent electric dipole moment. B. ( C O_{2} ) molecule is a polar molecule. C ( . H_{2} O ) is a non-polar molecule. The dipole field at large distances falls of as ( frac{1}{r^{2}} ) |
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276 | Two point charges ( q ) and ( -q ) are separated by a distance 2l, Find the flux of electric field strength vector across the circle of radius ( mathrm{R} ) placed with its centre coinciding with the midpoint of line joining the two charges in the perpendicular plane. | 12 |

277 | The device, which can be used to detect whether an object is charged, is: A. telescope B. microscope c. electroscope D. none of the above |
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278 | A point charge ( q ) is kept at a distance of 2R from centre of an uncharged spherical shell of radius R. The potential at centre of the shell due to charges induced on shell is A ( cdot frac{q}{4 pi E_{0} R} ) В ( cdot frac{q}{4 pi E_{0} 2 R} ) c. ( frac{-q}{4 pi E_{0} R} ) D. zero |
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279 | A hollow cylinder has a charge ( q ) coulomb within it. If ( phi ) is the electric flux in units of voltmeter associated with the curved surface ( B ), the flux linked with the plane surface ( A ) in units of voltmeter will be A ( cdot frac{q}{epsilon_{0}}-phi ) B ( cdot frac{1}{2}left(frac{q}{epsilon_{0}}-phiright) ) c. ( frac{q}{2 epsilon_{0}} ) D. ( frac{phi}{3} ) |
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280 | A uniform vertical electric field ( boldsymbol{E} ) is established in the space between two large parallel plates. A small conducting sphere of mass ( boldsymbol{m} ) is suspended in the field from a string of length ( L ). If the sphere is given ( a+q ) charge and the lower plate is charged positively, the period of oscillation of this pendulum is : ( ^{mathrm{A}} cdot 2 pi sqrt{frac{L}{g}} ) в. ( 2 pi sqrt{frac{L}{g+frac{q E}{m}}} ) c. ( _{2 pi} sqrt{frac{L}{g-frac{q E}{m}}} ) D. ( 2 pi sqrt{frac{L}{left(g^{2}+left(frac{q E}{m}right)^{2}right)^{1 / 2}}} ) |
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281 | Let ( boldsymbol{E}_{1}(boldsymbol{r}), boldsymbol{E}_{2}(boldsymbol{r}) ) and ( boldsymbol{E}_{3}(boldsymbol{r}) ) be the respective electric fields at a distance from a point charge ( Q, ) an infinitely long wire with constant linear charge density ( lambda, ) and an infinite plane with uniform surface charge density ( sigma . ) If ( E_{1}left(r_{0}right)= ) ( E_{2}left(r_{0}right)=E_{3}left(r_{0}right) ) at a given distance ( r_{0} ) then : A ( cdot Q=4 sigma pi r_{0}^{2} ) B. ( r_{0}=frac{lambda}{2 pi sigma} ) c. ( E_{1}left(frac{r_{0}}{2}right)=2 E_{2}left(frac{r_{0}}{2}right) ) D. ( E_{2}left(frac{r_{0}}{2}right)=4 E_{3}left(frac{r_{0}}{2}right) ) |
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282 | An electric dipole has the magnitude of its charge as ( q ) and its dipole moment is p. It is placed in a uniform electric field E. If its dipole moment is along the direction of the field, the force on it and its potential energy are respectively: A. q. E and p. E B. zero and minimum c. q. E and maximum D. 2q. E and minimum |
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283 | Consider a uniform electric field ( boldsymbol{E}= ) ( 3 times 10^{3} hat{i} N / C . ) What is the flux of this field through a square of ( 10 mathrm{cm} ) on a side whose plane is parallel to the yz plane? A ( cdot 30 mathrm{Nm}^{2} / mathrm{C} ) В. ( 40 mathrm{Nm}^{2} / mathrm{C} ) c. ( 50 N m^{2} / C ) D. ( 60 mathrm{Nm}^{2} / mathrm{C} ) |
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284 | An electron is moving in a uniform horizontal electric field. If the acceleration of electron is ( 45^{circ} ) downward to the horizontal, then the field intensity in newton/coloumb will be |
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285 | Two equal charges are separated by a distance ( d . A ) third charge placed on a perpendicular bisector at ( x ) distance will experience maximum coulomb force when : A ( cdot x=frac{d}{sqrt{2}} ) B. ( x=frac{d}{2} ) c. ( _{x}=frac{d}{2 sqrt{2}} ) D. ( _{x}=frac{d}{2 sqrt{3}} ) |
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286 | Consider a hemispherical surface of radius ( r, ) a positive point charge ( q ) is kept at the centre of hemisphere. The electric flux through this hemisphere is A . zero в. ( frac{q}{varepsilon_{0}} ) c. ( frac{q}{2 varepsilon_{0}} ) D. ( frac{2 q}{varepsilon_{0}} ) |
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287 | The figure shows the electric field lines a round a conductor. (a) At which of the four points is the field strongest? (b) At which point is there a negative charge? |
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288 | Mark the correct options A. Gauss law is valid only for unsymmetrical charge distributions B. Gauss law is valid only for charge placed in vacuum C. The electric field calculated by Gauss law is the field due to the charges outside the Gaussian surface D. The flux of the electric field through a closed surface due to all the charges is equal to the flux due to the charges enclosed by the surface |
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289 | Net charge within an imaginary cube drawn in a uniform electric field is always zero. Is this statement true or false. |
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290 | An electric dipole as shown is free to move and rotate.lt will A. Rotate clock – wise and move to the left B. Rotate anti clock wise and move to the right C. Rotate clock wise and move to the right D. Rotate anticlockwise and move to the left |
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291 | Positive electric flux indicates that electric lines of force are directed A. outwards B. inwards c. either (a) or (b) D. none of these |
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292 | A linear charge having linear charge density ( lambda ), penetrates a cube diagonally and then it penetrate a sphere diametrically as shown. What will be the ration of flux coming out of cube and sphere. ( ^{A} cdot frac{1}{2} ) в. ( frac{2}{sqrt{3}} ) c. ( frac{sqrt{3}}{2} ) ( D ) |
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293 | The gold leaf electroscope is charged so that its leaves somewhat diverge. If ( X ) rays are incident on the electroscope then A. the divergence will decrease B. the divergence of leaves will remain unchanged c. the gold leaves will melt D. the divergence will increase |
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294 | What happens when some charge is placed on a soap bubble? A. Its radius decreases B. Its radius increases c. The bubble collapses D. None of these |
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295 | A closed surface S is constructed around a conducting wire connected to a battery and switch (Fig) As the switch is closed, the free electrons in the wire start moving along the wire. In any time interval, the number of electrons entering the closed surface ( S ) is equal to the number of electrons leaving it. After closing the switch, the flux of the electric field through the closed surface will : This question has multiple correct options A. increase B. decrease C. remain unchanged D. be zero |
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296 | A hollow spherical conducting shell of inner radius ( r_{1} ) and other radius ( r_{2} ) has a charge ( Q . A ) charge ( -q ) is placed at the centre of the sphere. The surface charge densities on the inner and outer surfaces of the sphere will be respectively:- ( ^{mathbf{A}} cdot frac{q}{4 pi r_{1}^{2}} ) and ( frac{q}{4 pi r_{2}^{2}} ) В ( cdot frac{-q}{4 pi r_{1}^{2}} ) and ( frac{Q+q}{4 pi r_{2}^{2}} ) c. ( frac{q}{4 pi r_{1}^{2}} ) and ( frac{Q-q}{4 pi r_{2}^{2}} ) D. ( _{text {O and }} frac{Q-q}{4 pi r_{2}^{2}} ) |
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297 | Calculate the charge on a body if ( 10^{5} ) electrons have been added to it ( mathbf{A} cdot-1.6 times 10^{-14} C ) В. ( 1.6 times 10^{-14} C ) c. ( 1.6 times 10^{14} C ) D. ( -1.6 times 10^{14} C ) |
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298 | Derive the expression for torque acting on a dipole ( boldsymbol{tau}=boldsymbol{P} . boldsymbol{E} sin boldsymbol{theta} ) | 12 |

299 | Negative electric flux indicates that electric lines of force are directed A. outwards B. inwards c. either (a) or (b) D. none of these |
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300 | Relative permittivity of water is ( 81 . ) If ( epsilon_{w} ) and ( epsilon_{0} ) are permittivities of water and vacuum respectively, then : A ( cdot epsilon_{0}=9 epsilon_{w} ) В . ( epsilon_{0}=81 epsilon_{w} ) ( mathbf{c} cdot epsilon_{w}=9 epsilon_{0} ) D. ( epsilon_{w}=81 epsilon_{0} ) |
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301 | Figure represents a negatively charged gold leaf electroscope. Of the parts ( A, B ) C, D and E, state whether they are an insulator or a conductor: ( A cdot A, B ) and ( E ) are conductors while ( D ) and ( C ) are insulators B. B, D and E are conductors while A and C are insulators ( c . A, D ) and ( E ) are insulators while ( B ) and ( C ) are conductors D. A, Dand E are conductors while B and C are insulators |
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302 | Gravitational force of the medium between the charges. A. depends B. does not depend c. sometimes depends D. None of these |
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303 | Electric flux through a surface of area ( 100 m^{2} ) lying in the xy plane is (in ( V ) -m) if ( overrightarrow{boldsymbol{E}}=hat{boldsymbol{i}}+sqrt{mathbf{2}} hat{boldsymbol{j}}+sqrt{mathbf{3} hat{boldsymbol{k}}} ) A. 100 B. 141.4 c. 173.2 D. 200 |
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304 | Which of the following statement is NOT true? A. lightning and spark from wollen clothing are essentially the same phenomena. B. when you rub a plastic scale on your dry hair, it acquires a charge. C. charge acquired by a glass rod when it is rubbed with silk is called as negative charge D. static charges are called so, because they donot move by themselves |
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305 | The potential energy for a force field ( overrightarrow{boldsymbol{F}} ) is given by ( U(x, y)=sin (x+y) ) Magnitude of the force acting on the particle of mass ( m ) at ( left(0, frac{pi}{4}right) ) is ( A ) B. ( sqrt{2} ) c. ( frac{1}{sqrt{2}} ) D. |
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306 | A charge ( q ) is placed at the corner of a cube of side ( a ). The electric flux passing through the cube is : A ( cdot frac{q}{a varepsilon_{0}} ) в. ( frac{q}{varepsilon_{0} a^{2}} ) c. ( frac{q}{4 pi varepsilon_{0} a^{2}} ) D. ( frac{q}{24 varepsilon_{0}} ) |
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307 | Two point charges ( +q ) and ( -q ) are placed at a distance ( x ) apart. A third charge is placed in such a way so that all the three charges are in equilibrium. Then : A. unknown charge is ( -4 q / 9 ) B. unknown charge is ( -9 q / 4 ) c. it should be at ( (x / 3) ) from smaller charge between them D. none of the above |
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308 | 4 charges are placed each at a distance a’ from origin. The dipole moment of configuration is : A ( cdot 2 q a hat{j} ) в. ( 3 q a hat{j} ) ( mathbf{c} cdot 2 a q[hat{i}+hat{j}] ) ( 0 . ) none |
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309 | The charge on a body is +1 C. Find the number of electrons in excess or deficit on the body. A ( cdot 6.25 times 10^{1} ) coulomb B. ( 6.25 times 10^{-18} ) coulomb c. ( 6.25 times 10^{-1} ) coulomb D. ( 6.25 times 10^{18} ) coulomb |
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310 | Four equal electric charges are arranged at the four corners of a square of side ( a . ) Out of these four charges, two charges are positive and placed at the ends of one diagonal. The other two charges are positive and placed at the ends of the other diagonal. The energy of the system is: This question has multiple correct options A. Negative B. Positive ( ^{mathrm{C}} ). ( _{text {Less than }} frac{1}{4 pi varepsilon_{0}}left(frac{2 q^{2}}{a}right) ) Deater than ( frac{1}{4 pi varepsilon_{0}}left(frac{2 q^{2}}{a}right) ) |
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311 | Two metal spheres ( A ) and ( B ) of exactly same mass are given equal positive and negative charges respectively. Their masses after charging: A. Remains unaffected B. Mass of ( A> ) mass of B c. Mass of ( A< ) mass of ( B ) D. Nothing can be said |
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312 | Determine the electric dipole moment of the system of three charges,placed on the vertices of an equilateral triangle as shown in the figure: A ( cdot(q l) frac{hat{i}+hat{j}}{sqrt{2}} ) В ( cdot sqrt{3} q l frac{hat{j}-hat{i}}{sqrt{2}} ) ( mathbf{c} .-sqrt{3} q l hat{j} ) D. ( 2 q l hat{j} ) |
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313 | Drive an expression for Electric field due to an Electric dipole at a point on the axial line. | 12 |

314 | ( mathrm{Q}(mathrm{charge})=? ) ( mathbf{A} cdot n / e ) B. ( n e ) ( c cdot e / n ) D. All |
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315 | How many point charges of same magnitude are required to constitute an electric dipole? | 12 |

316 | Two particles of charges and masses ( left(+q_{1}, m_{1}right) ) and ( left(-q_{2}, m_{2}right) ) are released at two different points in a uniform electric field E established in free space. If their separation remains unchanged find the separation ( l ) between them |
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317 | Identify the correct statement: A. The electric potential on bigger sphere is higher B. The electric potential on bigger sphere is lower C. The electric potential on the two spheres is equal D. None of these |
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318 | An early model for an atom considered it to have a positively charged point nucleus of charge ( Z e ), surrounded by a uniform density of negative charge upto a radius ( R ). The atom as a whole is neutral. The electric field at a distance ( r ) from the nucleus is ( (r<R) ) A ( cdot frac{Z e}{4 pi epsilon_{0}}left[frac{1}{r^{2}}-frac{r}{R^{3}}right] ) В ( cdot frac{Z e}{4 pi epsilon_{0}}left[frac{1}{r^{2}}-frac{r}{R^{2}}right] ) c. ( frac{Z e}{4 pi epsilon_{0}}left[frac{1}{R^{3}}-frac{r}{r^{2}}right] ) D. ( frac{Z e}{4 pi epsilon_{0}}left[frac{1}{R^{3}}+frac{r}{r^{2}}right] ) |
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319 | A silver wire of ( 1 mathrm{mm} ) diameter has a charge of 90 coulombs flowing in 1 hours and 15 minutes. Silver contains |
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320 | In above shown figure, a point charge ( +mathrm{Q} ) is fixed in position and five points are near the charge. An electric field is created by a point charge, then find out the point where the magnitude of the electric field would be least : ( A ) B. B ( c cdot c ) ( D ) E. |
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321 | Force between two charges separated by a certain distance in air is ( mathrm{F} ). If each charge is doubled and the distance between them is also doubled, force would be A. ( F ) в. ( 2 F ) ( c cdot frac{F}{2} ) D. ( 3 F ) |
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322 | The electric flux through the curve surface of a cone. Due to a charge ( Q ) placed at its mouth, A. ( phi=0 ) в. ( phi>frac{Q}{2_{varepsilon}} ) c. ( _{phi>frac{Q}{varepsilon_{0}}} ) D. ( phi=frac{Q}{z_{0}} ) |
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323 | If a conductor has a potential ( V neq 0 ) and there are no charges anywhere else outside, then A. there must be charges on the surface or inside itself B. there cannot be any charge in the body of the conductor c. there must be charges only on the surface D. there must be charges inside the surface |
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324 | When an electron is moving parallel to the conductor carrying current as shown we get A. region A has strong field B. region B has weak field C. region C has strong field D. electron will move towards conductor |
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325 | If an electric dipole is placed inside a sphere filled with water, then among the following which statement is correct? A. Water does not permit electric flux to enter into space B. Electric flux entering into sphere is equals to electric flux leaving the sphere c. Electric flux is coming towards the sphere D. Electric flux is coming out of sphere |
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326 | Electric lines of force about a negative point charge are: A . circular, anti-clockwise B. circular, clockwise c. radial, inwards D. radial, outwards |
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327 | The energy of a charged conductor is given by the expression: ( mathbf{A} cdot q^{2} / 2 c ) B. ( q^{2} / c ) ( mathbf{c} cdot 2 q c ) D. ( q / 2 c^{2} ),where q is charges on the conductor,c is its capacity |
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328 | A positive charge ( +Q ) is fixed at a point A. Another positively charged particle of mass ( mathrm{m} ) and charge ( +mathrm{q} ) is projected from a point B with velocity u as shown in the figure. The point B is at a large distance from ( A ) and at a large distance d from the line AC. The initial velocity is parallel to the line AC. The point ( C ) is at very large distance from A. Find the minimum distance (in meter) of ( +q ) from ( +Q ) during the motion. ( [text { take } Q q= ) ( left.4 pi epsilon_{0} m u^{2} dright] ) A. ( d(1+sqrt{2}) ) B . ( d(sqrt{2}-1) ) c. ( frac{d}{(1+sqrt{2})} ) D. ( frac{d}{(sqrt{2}-1)} ) |
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329 | Two uniformly charged plates are pictured above, with four evenly spaced points shown along a horizontal lines between the plates.What is the correct rank of strength of the electric field at the points, greatest first? A. 1,2,3,4 B. 4, 3, 2,1 C. The electric field strength is the same at all points D. 1 and 4 tie, 2 and 3 tie ( mathrm{E} cdot 2 ) and 3 tie, 1 and 4 tie |
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330 | ( boldsymbol{R} ) that carries a charge uniformly distributed throughout its volume. The volume charge density is ( rho . ) A Gaussian sphere of radius ( a ) is imagined that is concentric to the charged sphere. If ( a>R, ) what is the charge enclosed in |
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331 | For the electrostatic charge system as shown in Fig. 3.121 , find a. The net force on electric dipole, and b. Electrostatic energy of the system |
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332 | All free electric charges can be ( (e=operatorname{single} ) unit of charge i.e. the magnitude of charge on electron This question has multiple correct options A. odd multiples of ( e ) B. fractional multiples of ( e ) c. even multiples of ( e ) D. negative multiples of ( e ) |
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333 | A 10 pF parallel plate capacitor is charged with a ( 4.0 mathrm{V} ) battery. While the capacitor is still connected to the battery, a dielectric slab ( ( k=5.0 ) ) is inserted between the plates to completely fill the gap. How much electric potential energy is stored in the capacitor after inserting the dielectric? begin{tabular}{l} A ( .5 .3 times 10^{-10} J ) \ hline end{tabular} В . ( 4.0 times 10^{-10} mathrm{J} ) c. ( 4.6 times 10^{-10} J ) D. ( 5.6 times 10^{-10} mathrm{J} ) |
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334 | Charge density is a measure of electric charge per unit volume of space, A. in one dimension B. in two dimensions c. in three dimensions D. All of the above |
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335 | ( A ) and ( B ) are two hollow metal spheres of radii ( 50 c m ) and ( 1 m ) carrying charges ( 0.6 mu C ) and ( 1 mu C ) respectively. They are connected externally by a conducting wire. Now the charge flows from : A. ( A ) to ( B ) till the charges become equal B. ( A ) to ( B ) till the potentials become equal c. ( B ) to ( A ) till the charges become equal D. ( B ) to ( A ) till the potentials become equal |
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336 | topp ( E ) ( Q ) туре уоиг question 3 |
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337 | 彥光 ( (infty) ) ( frac{x+14}{x+1} ) ( frac{x}{10} ) |
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338 | An infinitely large thin plane sheet has a uniform surface charge density ( +sigma ) Obtain the expression for the amount of work done in bringing a point charge ( q ) from infinity to a point, distant ( r, ) in front of the charged plane sheet. |
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339 | The mass of proton is 1836 times that of an electron. An electron and a proton are projected into a uniform electric field in a direction perpendicular to the field with equal initial kinetic energies, then: A. the electron trajectory is less curved than the proton trajectory B. the proton trajectory is less curved than the electron trajectory c. both trajectories are equally curved D. both trajectories will be straight |
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340 | The electric field for ( boldsymbol{R}_{1}<boldsymbol{r}<boldsymbol{R}_{2} ) is ( operatorname{given} operatorname{by} boldsymbol{E}=frac{Q}{boldsymbol{X} boldsymbol{pi} varepsilon_{0} r^{2}}left[frac{r^{3}-boldsymbol{R}_{1}^{3}}{R_{2}^{3}-boldsymbol{R}_{1}^{3}}right] . ) Find ( mathbf{X} ? ) |
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341 | Mark out the correct options. A. The total charge of the universe is constant B. The total positive charge of the universe is constant. C. The total negative charge of the universe is constant D. The total number of charged particles in the universe is constant |
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342 | Three charged particles are in equilibrium under their electrostatic forces only: This question has multiple correct options A. The particles must be collinear B. All the charges cannot have the same magnitude c. All the charges cannot have the same sign D. The equilibrium is unstable |
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343 | Which of the following statements is not true about electric field lines? A. Electric field lines start from positive charge and end at negative charge B. Two electric field lines can never cross each other C. Electrostatic field lines do not form any closed loops D. Electric field lines cannot be taken as continuous curve |
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344 | mass ( m ) is hanging in front of a large non-conducting sheet having surface charge density ( sigma ). If suddenly a charge ( +q ) is given to the bob ( & ) it is released from the position shown in figure. The maximum angle through which the string is deflected from vertical is ( x tan ^{-1}left(frac{sigma q_{0}}{2 varepsilon_{0} m g}right) . ) Find ( x ) |
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345 | is the electrical charges generated by rubbing. A. electricity B. static charge ( c . ) both a and ( b ) D. none of the above |
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346 | and ( C ) have radii ( a, b ) and ( c(a<b<c) ) and surface charge densities on them ( operatorname{are} sigma,-sigma, ) and ( sigma ) respectively. The values of ( boldsymbol{V}_{boldsymbol{A}} ) and ( boldsymbol{V}_{boldsymbol{B}} ) will be: A ( cdot frac{sigma}{epsilon_{0}}(a-b+c), frac{sigma}{epsilon_{0}}left(frac{a^{2}}{b}-b+cright) ) B ( cdot frac{sigma}{epsilon_{0}}(a-b+c), frac{sigma}{epsilon_{0}} frac{a^{2}}{c} ) c. ( frac{sigma}{epsilon_{0}}(a+b-c), frac{sigma}{epsilon_{0}}left(frac{a^{2}}{c}-b+cright) ) ( stackrel{sigma}{epsilon_{0}}left(frac{a^{2}}{c}-frac{b^{2}}{c}+cright), frac{sigma}{epsilon_{0}}(a-b+c) ) |
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347 | A small metal sphere carrying charge ( +Q ) is located at the centre of a spherical cavity in a large uncharged metallic spherical shell. Write the charges on the inner and outer surfaces of the shell. Write the expression for the electric field at the point ( P_{1} ) is ( E=frac{x Q}{4 pi epsilon_{0} r_{1}^{2}} . ) Then the value of ( x ) is : |
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348 | A electric dipole having charge ( q ) and ( -q ) are placed at distance ( ^{prime} d^{prime} ) is in equilibrium in a uniform electric filed ( boldsymbol{E} ) Each charge has mass ‘ ( m^{prime} . ) If dipole is displayed by small angle. Then its angular frequency of oscillation is: A ( cdot sqrt{frac{3 q E}{m d}} ) в. ( sqrt{frac{q E}{2 m d}} ) c. ( sqrt{frac{2 q E}{m d}} ) D. ( sqrt{frac{2 q E}{3 m d}} ) |
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349 | A uniformly charged non-conducting thin hemispherical shall is shown in figure. What is correct direction of net electric field at any point on its open plane surface? ( A ) B. 2 ( c cdot 3 ) D. 4 |
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350 | A point charge ( q ) is situated at a distance ( r ) on axis from one end of a thin conducting rod of length ( L ) having a charge ( Q ) (Uniformly distributed along its length). The magnitude electric force between the two is A ( cdot frac{k q^{2}}{r(r+L)} ) в. ( frac{K Q q}{r^{2}} ) c. ( frac{K Q q}{r(r-L)} ) D. ( frac{K Q q}{r(r+L)} ) |
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351 | The flux passing through the surface ( S_{5} ) will be ( mathbf{A} cdot-0.135 N m^{2} C^{-} ) B. ( -0.054 N m^{2} C^{-1} ) ( c cdot 0.081 N m^{2} C^{-1} ) ) ( 0.054 N m^{2} C^{-1} ) |
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352 | Determine ( V ) for ( r<R ) A ( cdot frac{rho}{6 epsilon_{0}}left(3 R^{2}right) ) В. ( frac{rho}{6 epsilon_{0}}left(r^{2}right) ) c. ( frac{rho}{6 epsilon_{0}}left(3 R^{2}-r^{2}right. ) D. ( frac{rho}{6 epsilon_{0}}left(3 R^{2}+r^{2}right) ) |
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353 | Which of the following is an insulator? A. woodd B. Iron c. carbon D. Silver |
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354 | A charged oil drop is suspended in uniform field of ( 3 times 10^{4} V / m ) so that it neither falls nor rises. The charge on the drop will be (take the mass of the charge ( =mathbf{9 . 9} times mathbf{1 0}^{-mathbf{1 5}} ) and ( boldsymbol{g}=mathbf{1 0} ) A . ( 3.3 times 10^{-18} mathrm{C} ) B . ( 3.2 times 10^{-18} mathrm{C} ) c. ( 1.6 times 10^{-18} mathrm{C} ) D. ( 4.8 times 10^{-18} mathrm{C} ) |
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355 | A charge q is accelerated through a potential difference V. It is then passed normally through a uniform magnetic field, where it moves in a circle of radius r. The potential difference required to move it in a circle of radius ( 2 r ) is? A . 2 v B. 4 v c. ( 1 v ) D. 3 |
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356 | State whether true or false. A jute string can be used to make a circuit instead of metal wires, A. True B. False |
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357 | Two metal plates having a potential difference of ( 800 mathrm{V} ) are ( 2 mathrm{cm} ) apart. It is found that a particle of mass ( 1.96 times ) ( 10^{-15} K g ) remain suspended in the region between the plates. The charge on the particle must be: ( A cdot 3 e ) B. ( 4 e ) ( c cdot 6 e ) D. ( 8 e ) |
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358 | A solid conducting sphere having a charge ( Q ) is surrounded by an uncharged concentric conducting hollow spherical shell. Let the potential difference between the surface of the solid sphere and that of the outer surface of the hollow shell be ( V . ) If the shell is now given a charge of ( 3 Q ) the new potential difference between the same two surfaces is : A. ( V ) B. 2 ( V ) ( c cdot 4 v ) D. ( -2 V ) |
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359 | Find the magnitude of a charge which produces an electric field of strenght is ( 18 times 10^{3} N C^{-1} ) at a distance of ( 5 mathrm{m} ) in air. A. ( 50 mu c ) B. ( 100 mu c ) ( c cdot 25 mu c ) D. 250 muc |
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360 | uniformly distributed charge ( Q ). The rod has been bent in a ( 120^{circ} ) circular arc of radius ( r . ) In terms of ( Q ) and ( r, ) what is the electric field ( vec{E} ) due to the rod at point ( boldsymbol{P} ? ) A ( quad vec{E}=frac{3 sqrt{3} lambda}{8 pi^{2} epsilon_{0} r^{2}} hat{i} ) where ( lambda=frac{2 Q}{3 pi r} ) B ( quad vec{E}=frac{3 sqrt{3} lambda}{8 pi^{2} epsilon_{0} r^{2}} hat{i} ) where ( lambda=frac{3 Q}{2 pi r} ) C ( quad vec{E}=frac{3 sqrt{3} lambda}{8 pi^{2} epsilon_{0} r^{2}} hat{j} ) where ( lambda=frac{2 Q}{3 pi r} ) D ( quad vec{E}=frac{3 sqrt{3} lambda}{8 pi^{2} epsilon_{0} r^{2}} hat{j} ) where ( lambda=frac{3 Q}{2 pi r} ) |
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361 | Two bodies are changed by rubbing one against the other. During the process, one becomes positively charged while the other becomes negatively charged. Then, A. mass of each body remains unchanged. B. mass of each body changes marginally. C. mass of each body changes slightly and hence the total mass. D. mass of each body changes slightly but the total mass remains the same. |
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362 | If two bodies ( A ) and ( B ) (A bigger in size than ( mathrm{B} ) ) are rubbed together, then : A. A and B get equal and opposite charges B. A and B get equal and similar charges c. A gets more charge than B, but of opposite kind D. A gets less charge than B, but of same kind |
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363 | In free space, a particle A of charge ( 1 mu C ) is held fixed at a point P. Another particle B of the same charge and mass ( 4 mu g ) is kept at a distance of 1 mm from P. if ( mathrm{B} ) is released, then its velocity at a distance of ( 9 mathrm{mm} ) from ( mathrm{P} ) is : ( left[text { Take } frac{1}{4 pi varepsilon_{0}}=9 times 10^{9} N m^{2} C^{-2}right] ) A ( .2 .0 times 10^{3} mathrm{m} / mathrm{s} ) в. ( 3.0 times 10^{4} mathrm{m} / mathrm{s} ) c. ( 1.5 times 10^{2} m / s ) D. ( 1.0 m / s ) |
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364 | ‘The charge on a body cannot be ( mathbf{A} cdot e ) B. c. ( 1.5 e ) D. all the above |
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365 | A plane area of ( 100 mathrm{cm}^{2} ) is placed in uniform electric field of ( 100 N / C ) such that the angle between area vector and electric field is ( 60^{circ} . ) The electric flux over the surface is A . ( 0.5 mathrm{wb} ) B. ( 5 mathrm{Wb} ) ( c cdot 1 w b ) D. |
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366 | Materials which allow larger currents to flow through them are called: A. insulators B. conductors c. semiconductors D. alloys |
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367 | Calculate the electric field intensity required to just support a water drop let of mass ( 10^{-7} k g ) and having a charge of ( +4.0 times 10^{-13} C ) |
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368 | An electric dipole of moment ‘p’ is placed in an electric field of intensity ‘E’. The dipole acquires a position such that the axis of the dipole makes an angle 0 with the direction of the field. Assuming that the potential energy of the dipole to be zero when ( theta=90^{0} ), the torque and the potential energy of the dipole will respectively be: A. ( p E sin theta, 2 p E cos theta ) B. ( p E cos theta,-p E sin theta ) c. ( p E sin theta,-p E cos theta ) D. ( p E sin theta,-2 p E cos theta ) |
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369 | The number of electric field lines ( operatorname{crossing} ) an area ( Delta S ) is ( n_{1} ) when ( Delta vec{S} | vec{E}_{1} ) while the number of field lines crossing the same area is ( n_{2} ) when ( Delta overrightarrow{boldsymbol{S}} ) makes an angle of ( 30^{circ} ) with ( vec{E} ). Then A ( cdot n_{1}=n_{2} ) в. ( n_{1}>n_{2} ) c. ( n_{1}<n_{2} ) D. cannot say anything |
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370 | Coulomb’s law relates two charges and distance between them describing the electric force as being: A. proportional to the sum of the charges B. inversely proportional to the distance between charges C. proportional to the product of the charges and inversely proportional to the distance D. proportional to the product of the charges and inversely proportional to the square of the distance |
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371 | Use Gauss’s law to show that due to a uniformly charged spherical shell of radius ( mathrm{R} ), the electric field at any point situated outside the shell at a distance r from its centre is equal to the electric field at the same point, when the entire charge on the shell were concentrated at its centre. Also plot the graph showing the variation of electric field with ( r, ) for ( r leq R ) and ( r geq R ) |
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372 | Figure shows tracks of three charged particles in a uniform electrostatic field. Give the signs of the three charges.Which particle has the highest charge to mass ratio? | 12 |

373 | Three charges ( 4 q, Q ) and ( q ) are in straight line in the position o, ( 1 / 2 ) and I respectively the resultant force on q will be A. B. ( c cdot-1 ) D. 0.5 |
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374 | An ebonite rod rubbed with fur and a glass rod rubbed with silk cloth are brought nearer to each other. Then : A. They will attract each other B. They will repel each other C. Nothing will happen to them D. They will get heated up |
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375 | When we touch a steel rod and a paper simultaneously, we feel that the rod is colder because: A. iron being a good conductor conducts more heat from our body B. paper being a good conductor conducts more heat from our body C. more heat flows from the iron to our body D. more heat flows from the paper to our body |
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376 | A small conducting sphere of radius ( a ) carrying a charge ( +Q, ) is placed inside an equal and oppositely charged conducting shell of radius ( b ) such that their centers coincide. Determine the potential at a point which is at a distance ( c ) from center such that ( a<c<b ) A. ( k(Q / c+Q / b) ) в. ( k(Q / a+Q / b) ) c. ( k(Q / a-Q / b) ) D. ( k(Q / c-Q / b) ) |
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377 | An electric dipole ( pm 4 mu C ) is kept at coordinate points (1,0,4) are kept at ( (2,-1,5), ) the electric field is given by ( vec{E}=20 hat{i} N C^{-1} . ) Calculate the torque on the dipole. |
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378 | 11 the highest charge? ( mathbf{A} ) ( B ) ( mathbf{C} ) D. Cannot be ascertained |
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379 | The existence of a negative charge on a body implies that it has: A. lost some of its electrons B. lost some of its atoms c. acquired some electrons from outside D. acquired some protons from outside |
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380 | Select the odd one out w.r.t. conduction of heat (wood, paper, plastic, silver) A . silver B. woodd c. paper D. plastic |
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381 | The nucleus of helium atom contains two protons that are separated by distance ( 3.0 times 10^{-15} ) m. The magnitude of the electrostatic force that each proton exerts on the other is: A . ( 20.6 N ) B. 25.6 N c. ( 15.6 N ) D. ( 12.6 N ) |
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382 | A hollow metal sphere of radius ( R ) is charged with a charge ( Q . ) The electric potential and intensity inside the sphere are respectively: A ( cdot frac{Q}{4 pi epsilon_{0} R^{2}} ) and ( frac{Q}{4 pi epsilon_{0} R} ) B. ( frac{Q}{4 pi epsilon_{0} R} ) and zero c. zero and sero D. ( frac{4 pi epsilon_{0} Q}{R} ) and ( frac{Q}{4 pi epsilon_{0} R^{2}} ) |
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383 | A positive charge q is placed in a spherical cavity made in a positively charged sphere. The centres of sphere and cavity are displaced by a small distance ( vec{l} ). Force on charge q is : A . in the direction parallel to vector ( vec{l} ) B. in radial direction c. in a direction which depends on the magnitude of charge density in sphere D. direction can not be determined |
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384 | When an electron and a proton are placed in an electric field A. The electric forces acting on them are equal in magnitude as well as direction B. Only the magnitudes of forces are same C. Accelerations produced in them are same D. Magnitudes of accelerations produced in them are same |
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385 | A short electric dipole (which consists of two point charges ( +boldsymbol{q} ) and ( -boldsymbol{q} ) ) is placed at the centre 0 and inside a large cube (ABCDEFGH) of length L, as shown in figure. The electric flux, emanating through the cube is: ( A cdot q / 4 pi varepsilon_{0} L ) B. zero c. ( q / 2 pi varepsilon_{0} L ) D ( cdot q / 3 pi varepsilon_{0} L ) |
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386 | Paper snippets attracted by a charged CD is an example of A. charging by induction B. charging by conduction c. charging by ionisation D. charging by transmission |
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387 | Two infinite parallel metal planes, contain electric charges with charge densities ( +sigma ) and ( -sigma ) respectively and they are separated by a small distance in air. If the permittivity of air is ( epsilon_{0}, ) then the magnitude of the field between the two planes with its direction will be: A ( cdot sigma / epsilon_{0} ) towards the positively charge plane B . ( sigma / epsilon_{0} ) towards the negatively charged plane C ( cdot sigma /left(2 epsilon_{0}right) ) towards the positively charged plane D. 0 and towards any direction |
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388 | Similar charges each other whereas opposite charges each other. A. repel, attract B. attract, repel c. repel, repel D. attract, attract |
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389 | Coulomb’s law states that the electric force becomes weaker with increasing distance, Suppose that instead, the electric force between two charged particles were independent of distance. In this case, would a neutral insulator still be attracted towards the comb. |
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390 | Three charges are placed at the vertices of an equilateral triangle of side a as shown in the figure. The force experienced by the charge plced at the vertex ( A ) in a direction normal to ( B C ) is : ( A ) ( mathbf{B} cdot-Q^{2}left(4 pi varepsilon_{0} a^{2}right) ) c. zero ( ^{mathrm{D}} cdot frac{Q^{2}}{left(2 pi varepsilon_{0} a^{2}right)} ) |
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391 | A rubbed comb can lift paper pieces. why? |
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392 | open end of a cylindrical vessel of radius ( R ) and height ( 2 R ) as shown in figure. the flux of the electric field through the surface (curved surface ( + ) base ) of the vessel is ( mathbf{A} cdot frac{Q}{varepsilon_{0}} ) B. ( frac{Q}{2 varepsilon_{text {d }}} ) ( c cdot frac{Q}{4 varepsilon_{0}} ) D. ( frac{Q}{sqrt{5} varepsilon_{0}} ) |
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393 | ( n ) identical charged drops having charge ( q_{0}, ) potential ( V_{0}, ) capacity ( C_{0} ) and energy ( E_{0}, ) coalesce to form a big drop. The new potential, charge, capacity, energy stored will be: B ( cdot frac{2}{n^{3}} V_{0} ; frac{q_{0}}{n_{0}} ; quad n^{frac{1}{3}} C_{0} ; quad n^{frac{3}{5}} U_{0} ) D. ( frac{2}{n^{3}} V_{0} ; frac{q_{0}}{n} ; n^{frac{2}{3}} C_{0} ; n^{frac{5}{3}} U_{0} ) |
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394 | Gauss’s law follows This question has multiple correct options A. Coulomb’s law B. Superposition principle C. Faraday’s law D. Quantisation principle |
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395 | An infinite parallel plane sheet of a metal is charged to charge density ( sigma ) coulomb per square metre in a medium of dielectric constant ( K . ) Intensity of electric field near the metallic surface will be : ( ^{mathrm{A}} cdot_{E}=frac{sigma}{varepsilon_{0} K} ) в. ( _{E}=frac{sigma}{2 varepsilon_{0}} ) ( ^{mathrm{c}}=_{E}=frac{sigma}{2 varepsilon_{varepsilon} K} ) D. ( _{E}=frac{K sigma}{2 varepsilon_{0}} ) |
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396 | From below which is the example of insulators. A. Metallic elements B. Non Metallic elements c. graphite D. acqueous solution of salt |
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397 | If the charge density at each small drop be ( sigma, ) then charge density in the larger drop is A ( cdotleft[4 n^{1 / 3} sigmaright] ) B . ( left[n^{1 / 3} sigmaright] ) c. ( left[3 n^{1 / 3} sigmaright] ) D. ( left[2 n^{1 / 3} sigmaright] ) |
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398 | A hollow dielectric sphere has ( R_{1} ) and ( R_{2} ) as its inner and outer radii. The total charge carried by the sphere is ( +mathrm{Q} ) which is uniformly distributed throughout the dielectric sphere between ( R_{1} ) and ( R_{2} ). The electric field for ( R_{1}<r<R_{2} ) is given by : ( ^{A} cdot frac{Q}{4 pi r in R_{1}} ) в. ( frac{Q}{4 pi epsilon r_{2}} ) c. ( frac{Q}{4 pi in R_{1}^{2}} ) D. ( frac{Qleft(r^{3}-R_{1}^{2}right)}{4 pi in r^{2}left(R_{2}^{3}-R_{1}^{3}right)} ) |
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399 | A molecule of a substance has a permanent electric dipole moment of magnitude ( 10^{-30} mathrm{cm} . ) A mole of this substance is polarised by applying a strong electrostatic field of magnitude ( 10^{7} mathrm{V} m^{-1} ). the direction of the field is changed by an angle ( 60 . ) The heat released by the substance In aligning its dipole along the new direction of the field is: A . – 6 J B. -3 J c. 3 ( D .6 ) |
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400 | The maximum Coulomb force that can act on the electron due to the nucleus in a hydrogen atom will be:- A. ( 0.82 times 10^{-8} N ) N ( . . ~ ) В. ( 0.082 times 10^{-8} N ) c. ( 8.2 times 10^{-8} N ) D. ( 820 times 10^{-8} N ) |
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401 | The electronic charge ‘e’ is the possible charge. A. maximum B. minimum c. avarage D. total |
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402 | You are provided with a negatively charged gold leaf electroscope. State and explain what happens when an ebonite rod rubbed with fur is brought near the disc of electroscope. A. divergence increases B. divergence decreases c. divergence remains same D. can’t say |
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403 | For the given situation irrespective of the magnitude of charge and their separation it is found that total energy of the system (i.e. electric potential energy and their K.E.) is related to K.E. by the equation total energy = -kinetic energy ( (k) ) Which of the following gives the correct value of potential energy of the system? A ( cdot frac{q^{2}}{4 pi varepsilon_{0} R} ) В. ( frac{q^{2}}{8 pi varepsilon_{0} R} ) ( ^{mathbf{C}}-frac{q^{2}}{4 pi varepsilon_{0} R} ) ( ^{mathrm{D}}-frac{q^{2}}{8 pi varepsilon_{0} R} ) |
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404 | Find the net flux through the cylinder. ( mathbf{A} cdot-0.125 N m^{2} / C ) B. ( -0.25 N m^{2} / C ) ( mathbf{C} cdot 0.25 N m^{2} / C ) D. ( 0.125 N m^{2} / C ) |
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405 | If the electric field to the left of two sheets is ( K sigma / varepsilon_{0} . ) Find K? |
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406 | Two small identical electrical dipoles ( A B ) and ( C D ) each of dipole moment ( vec{p} ) are kept at an angle of ( 120^{circ} ) as shown in the figure. What is the resultant dipole moment of this combination ? If this system is subjected to electric field ( (vec{E}) ) directed along ( +boldsymbol{X} ) direction, what will be the magnitude and direction of the torque acting on this? |
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407 | A pyramid has a square base of side ( a ) and four faces which are equilateral triangles. A charge ( Q ) is placed on the centre of the base of the pyramid. What is the net flux of electric field emerging from one of the triangular faces of the pyramid? A. 0 в. ( frac{Q}{8 epsilon_{0}} ) c. ( frac{Q a^{2}}{8 epsilon_{0}} ) D. ( frac{Q}{2 epsilon_{0}} ) |
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408 | A thin spherical conducting shell of radius ( mathrm{R} ) has a charge ( mathrm{q} ). Another charge Q is placed at the centre of the shell. The electrostatic potential at a point ( mathbf{P} ) which is at a distance ( frac{boldsymbol{R}}{mathbf{2}} ) from the centre of the shell is: ( ^{mathbf{A}} cdot frac{2 Q}{4 pi epsilon_{0} R}-frac{2 q}{4 pi epsilon_{0} R} ) В. ( frac{2 Q}{4 pi epsilon_{0} R}+frac{2 q}{4 pi epsilon_{0} R} ) c. ( frac{(q+Q)}{4 pi epsilon_{0} R}+frac{2}{R} ) D. ( frac{2 Q}{4 pi epsilon_{0} R} ) |
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409 | toppr Q Type your question of the electric filed ( |bar{E}(r)| ) and the electric potential ( V(r) ) with the distance ( r ) from the centre, is best represented by which graph ? 4 3 ( c ) ( D ) |
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410 | Two identical metallic spheres ( A ) and ( B ) of exactly equal masses are given equal positive and negative charge respectively. Then: A. mass of ( A> ) Mass of B B. mass of A <Mass of B c. mass of ( A= ) Mass of B D. mass of ( A geq ) Mass of B |
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411 | Number of electrons constituting ( 1 C ) electric charge is A ( cdot 6.25 times 10^{18} ) electrons B. ( 1.6 times 10^{-19} ) electrons C. ( 6.25 times 10^{-19} ) electrons D. ( 1.6 times 10^{-18} ) electrons |
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412 | What is the minimum possible amount of charge? A. Electronic charge ( e ) B. Electronic charge ( 2 e ) C . Electronic charge ( frac{e}{2} ) D. Electronic charge ( frac{e}{sqrt{2}} ) |
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413 | Find the charge on the inner surface of the conducting concentric shell ( A cdot Q ) B. ( 2 Q ) ( c .-2 Q ) D. ( -Q ) |
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414 | Why is electrical wiring usually made from copper? A. Because copper is shiny B. Because copper conducts electricity c. Because copper is not magnetic D. none of these |
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415 | Suppose the exact charge neutrality does not hold in a world and the electron has a charge ( 1 % ) less in magnitude than the proton. Calculate the Coulomb force acting between two blocks of iron each of mass ( 1 k g ) separated by a distance of 1 m. The number of protons in an iron atom ( =26 ) and ( 58 k g ) of iron contains ( 6 times 10^{26} ) atoms. |
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416 | An electric dipole of momentum ( vec{p} ) is placed in a uniform electric field. The dipole is rotated through a very smal angle from equilibrium and is released. Prove that it executes simple harmonic motion with frequency ( f=frac{1}{2 pi} sqrt{frac{p E}{1}} ) Where, ( I= ) moment of inertia of the dipole. |
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417 | A charge ( Q ) is placed at each of two opposite corners of a square. A charge ( q ) is laced at each of the two opposite corners of the square. If the resultant electric field on ( Q ) is zero, then ( ^{mathbf{A}} cdot Q=-frac{q}{2 sqrt{2}} ) в. ( Q=-2 sqrt{2} q ) c. ( Q=-2 q ) |
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418 | A charged body possesses A. a positive charge B. a negative charge C. either a positive or a negative charge D. no charge |
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419 | An electric dipole moment ( vec{P}=(2.0 hat{i}+ ) ( 3.0 hat{j}) mu ) is placed in a uniform electric field ( overrightarrow{boldsymbol{E}}=(mathbf{3 . 0 hat { boldsymbol { i } }}+mathbf{2 . 0 hat { boldsymbol { k } }}) times mathbf{1 0}^{mathbf{5}} mathbf{N} boldsymbol{C}^{-mathbf{1}} ) This question has multiple correct options A . The torque that ( vec{E} ) exerts on ( mathrm{P} ) is ( (0.6 hat{i}-0.4 hat{j}-0.9 hat{k}) ) ( mathrm{Nm} ) B. The potential energy of the dipole is 0.9 J c. The potential energy of the dipole is 0.6 D. If the dipole is rotated in the electric field, the maximum potential energy of the dipole is 1.3 |
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420 | The intensity of an electric field between the plates of a charged condenser of plate area ( A ) will be : A ( . A /left(q varepsilon_{0}right) ) в. ( q A / varepsilon_{0} ) c ( cdot q /left(varepsilon_{0} Aright) ) D. none of these |
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421 | ( A ) and ( B ) are two points on the axis and the perpendicular bisector respectively of an electric dipole. ( A ) and ( B ) are far away from the dipole and at equal distance from it. The field at ( A ) and ( B ) ( operatorname{are} overrightarrow{boldsymbol{E}}_{boldsymbol{A}} ) and ( overrightarrow{boldsymbol{E}}_{boldsymbol{B}} ) ( mathbf{A} cdot vec{E}_{A}=vec{E}_{B} ) B . ( vec{E}_{A}=2 vec{E}_{B} ) c. ( vec{E}_{A}=-2 vec{E}_{B} ) D・ ( left|E_{B}right|=frac{1}{2}left|E_{A}right|, vec{E}_{B} ) is perpendicular to ( vec{E}_{A} ) |
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422 | Easy to shape materials like ceramics are used as A. conductors B. insulators c. electrodes. D. catalysts. |
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423 | Which of the following statement is NOT true? A. Lightning and spark from woolen clothing are essentially the same phenomena. B. When you rub a plastic scale on your dry hair, it acquires a charge. C. Charge acquired by a glass rod when it is rubbed with silk is negative charge. D. Static charges are called so, because they do not move by themselves. |
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424 | Inside a neutral metallic spherical shell a charge ( Q_{1} ) is placed, and outside the shell, a charge ( Q_{2} ) is placed. |
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425 | Choose the correct statement about electric charges: A. Two charges exert only electrical force on each other B. Two charges exert only magnetic forces on each other. C. Two charges interact electromagnetically. D. Two charges interact either electrically or magnetically. |
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426 | What happens when some charge is placed on a soap bubble? A. Its radius decreases B. Its radius increases c. The bubble collapses D. None of the above |
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427 | ( x ) if the potential to which the outer sphere is raised is ( x times 10^{3} V ) |
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428 | A hollow metallic sphere of radius R is given a charge ( Q ). Then, the potential at the centre is A. zero в. ( frac{1}{4 pi epsilon_{0}} cdot frac{Q}{R} ) c. ( frac{1}{4 pi epsilon_{0}} cdot frac{2}{Q} R ) D. ( frac{1}{4 pi epsilon_{0}} cdot frac{Q}{2 R} ) |
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429 | When the metal terminal of a gold-leaf electroscope is touched with a charged object, A. the gold leaves spread apart in a “v: B. the gold leaves close together. c. the gold leaves remain unaffected. D. None of these |
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430 | A Gaussian surface in the figure is shown by dotted line. The electric field on the surface will be: A. due to ( q_{1} ) and ( q_{2} ) only B. due to ( q_{2} ) only c. zero D. due to all |
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431 | (a) Define electric dipole moment. Is it a scalar or a vector? Derive the expression for the electric field of a dipole at a point on the equatorial plane of the dipole. (b) Draw the equipotential surface due to an electric dipole. Locate the points where the potential due to the dipole is zero. |
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432 | Coulomb’s Law is true for A ( . ) atomic distances ( left(=10^{-11} mathrm{m}right) ) B. nuclear distances ( left(=10^{-15} mathrm{m}right) ) C. charged as well as uncharged particles D. all the distances |
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433 | Which one of the following is an insulator? A. nichrome B. graphite c. human body D. bakelite |
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434 | Charges ( Q_{1} ) and ( Q_{2} ) lie inside and outside respectively of a closed surface S. Let ( mathrm{E} ) be the field at any point on ( mathrm{S} ) and ( phi ) be the flux of E over ( S ) This question has multiple correct options A ( cdot ) If ( Q_{1} ) changes, both ( mathrm{E} ) and ( phi ) will change B . If ( Q_{2} ) changes, E will change but ( phi ) will not change C. If ( Q_{1}=0 ) and ( Q_{2} neq 0, ) then ( E neq 0 ) but ( phi=0 ) D. If ( Q_{1} neq 0 ) and ( Q_{2}=0, ) then ( mathrm{E}=0 ) but ( phi neq 0 ) |
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435 | Both gravitational and electric forces are A. contact forces B. central forces c. attractive forces D. repulsive forces |
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436 | Assertion The effects of charge exchange are usually only noticed when at least one of the surfaces has a high resistance to electrical flow. Reason This is because the charges that transfer to or from the highly resistive surface are more or less trapped there for a long enough time for their effects to be observed. A. Both Assertion and Reason are correct and Reason is the correct explanation for Assertion B. Both Assertion and Reason are correct but Reason is not the correct explanation for Assertion c. Assertion is correct but Reason is incorrect D. Both Assertion and Reason are incorrect |
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437 | Let ( boldsymbol{E}_{a} ) be the electric field due to a dipole in its axial plane distant ( ell ) and ( boldsymbol{E}_{boldsymbol{q}} ) be the field in the equatorial plane distant ( l^{1}, ) then the relation between ( E_{a} ) and ( boldsymbol{E}_{boldsymbol{q}} ) will be : ( mathbf{A} cdot E_{a}=4 E_{q} ) В . ( E_{q}=2 E_{a} ) ( mathbf{c} cdot E_{a}=2 E_{q} ) D. ( E_{q}=3 E_{a} ) |
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438 | The addition of electrons in an atom is called A. reduction B. fusion c. magnetization D. None of these |
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439 | Two equal charges ‘ ( q ) ‘ of opposite sign are separated by a small distance ‘2a’. The electric intensity ‘ ( E ) ‘ at a point on the perpendicular bisector of the line joining the two charges at a very large distance ( ^{prime} r^{prime} ) from the line is : A ( cdot frac{1}{4 pi varepsilon_{0}} frac{q a}{r^{2}} ) В. ( frac{1}{4 pi varepsilon_{0}} frac{2 q a}{r^{3}} ) c. ( frac{1}{4 pi varepsilon_{0}} frac{2 q a}{r^{2}} ) D. ( frac{1}{4 pi varepsilon_{0}} frac{q a}{r^{3}} ) |
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440 | A circular loop of radius ( 2 mathrm{cm}, ) is placed in a time varing magnetic field with rate of ( 2 mathrm{T} / mathrm{sec} . ) Then induced electric field in this loop will be A. 0 B. 0. ( 02 mathrm{V} / mathrm{m} ) ( c cdot 0.01 v / m ) D. ( 2 v / m ) |
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441 | The cube as shown in Fig. has sides of length ( L=10.0 mathrm{cm} . ) The electric field is uniform, has a magnitude ( boldsymbol{E}=mathbf{4 . 0 0} times ) ( 10^{3} N C^{-1}, ) and is parallel to the ( x y- ) plane at an angle of ( 37^{circ} ) measured from the ( +x-a x i s ) towards the ( +y-a x i s ) Electric flux passing through surface ( boldsymbol{S}_{1} ) is A ( .-24 N m^{2} C^{-1} ) B. ( 24 N m^{2} C^{-1} ) ( mathbf{c} cdot 32 N m^{2} C^{-1} ) D. ( -32 N m^{2} C^{-1} ) |
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442 | Units of electric flux are : A ( cdot frac{N-m^{2}}{C^{2}} ) в. ( frac{N}{C^{2}-m^{2}} ) c. volt ( -m ) D. volt ( -m^{3} ) |
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443 | Assertion A charge ( q ) is placed on a height ( h / 4 ) above the centre of a square of side ( b ) The flux associated with the square is independent of side length. Reason Gauss’s law is independent of size of the Gaussian surface. A. Both Assertion and Reason are correct and Reason is the correct explanation for Assertion B. Both Assertion and Reason are correct but Reason is not the correct explanation for Assertion c. Assertion is correct but Reason is incorrect D. Both Assertion and Reason are incorrect |
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444 | The solid angle subtended by the total surface area of a sphere at the centre is A . ( 4 pi ) в. ( 2 pi ) ( c . pi ) D. ( 3 pi ) |
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445 | Two concentric spherical shells of radii a and 1.2 a have charges ( +mathrm{Q} ) and ( -2 mathrm{Q} ) respectively. At what distance from centre potential will be same as that of centre? A . 2 a B. 1.5 a c. 2.5 a D. 3a |
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446 | Assertion The electric potential due to an electric dipole at a point on the perpendicular bisector of the dipole axis is 0 . Reason Any point on the perpendicular bisector of the dipole axis is equidistant from the the two equal and opposite charges. A. Both Assertion and Reason are correct and Reason is the correct explanation for Assertion B. Both Assertion and Reason are correct but Reason is not the correct explanation for Assertion c. Assertion is correct but Reason is incorrect D. Both Assertion and Reason are incorrect |
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447 | Which of the following statement(s) is/are correct? This question has multiple correct options ( mathbf{A} cdot ) If the electric field due to a point charge varies as ( r^{-25} ) instead of ( r^{-2} ), then the Gauss law will still be valid. B. The Gauss law can be used to calculate the field distribution around an electric dipole. C. If the electric field between two point charges is zero somewhere, then the sign of the two charges is the same. D. The work done by the external force in moving a unit positive charge from point ( A ) at potential ( V_{A} ) to point ( B ) at potential ( V_{B} ) is ( left(V_{B}-V_{A}right) ) |
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448 | An electric dipole is along a uniform electric field. If it is deflected by ( 60^{circ} ) work done by the agent is ( 2 times 10^{-19} J ) Then the work done by an agent if it is deflected by ( 30^{circ} ) further is: A ( cdot 2.5 times 10^{-19} mathrm{J} ) В. ( 2 times 10^{-19} J ) c. ( 4 times 10^{-19} mathrm{J} ) D. ( 2 times 10^{-16} J ) |
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449 | A balloon is negatively charged by rubbing and then clings to a wall. Does this mean that the wall is positively charged ? why does the balloon eventually fall? |
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450 | Given a uniform electric field ( overrightarrow{boldsymbol{E}}=mathbf{5} times ) ( mathbf{1 0}^{3} hat{mathbf{i}} mathbf{N} / mathbf{C}, ) find the flux of this field through a square of ( 10 mathrm{cm} ) on a side whose plane is parallel to the ( boldsymbol{Y}-boldsymbol{Z} ) plane. What would be the flux through the same square if the plane makes a ( 30^{circ} ) angle with the ( $ $ X ) -axis? |
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451 | Materials that allow electrons to flow through them are known as A. Insulator B. Conductors c. Electrolytes D. Bases |
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452 | A thin insulating ring of radius ( R ) has a uniform linear charge density ( lambda ). Now a charge ( Q_{0} ) is placed at centre of this ring. The increment in the stretching force of the wire due to the charge ( Q_{0} ) is: A. ( frac{Q_{0} lambda}{2 pi varepsilon_{Omega}} ) в. ( frac{Q_{0} lambda}{4 pi varepsilon_{0} R} ) c. ( frac{3 Q_{0} lambda}{8 pi varepsilon_{0} R} ) D. ( frac{3 Q_{0} lambda}{4 pi varepsilon_{0} R} ) |
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453 | An ebonite rod rubbed with fur and a glass rod rubbed with silk cloth are brought nearer to each other. Then A. they will attract each other B. they will repel each other C. nothing will happen to them D. they will get heated up |
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454 | An isosceles right angle triangle of side d is placed in a horizontal plane. A point charge ( mathrm{q} ) is placed at a distance ( mathrm{d} ) vertically above from one of the corner as shown in the figure. Flux of electric field passing through the triangle is A ( cdot frac{q}{36 varepsilon_{0}} ) в. ( frac{q}{18 varepsilon_{0}} ) c. ( frac{q}{24 varepsilon_{0}} ) D. ( frac{q}{48 varepsilon_{0}} ) |
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455 | An oil drop, carrying six electronic charges and having a mass of ( 1.6 times ) ( 10^{-12} g, ) falls with some terminal velocity in a medium. What magnitude of vertical electric field is required to make the drop move upward with the same speed as it was formerly moving downward with? Ignore buoyancy A ( cdot 10^{5} N C^{-1} ) B . ( 10^{4} N C^{-1} ) c. ( 3.3 times 10^{4} N C^{-1} ) D. ( 3.3 times 10^{5} N C^{-1} ) |
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456 | Fill in the blank. Five point charges, each of value ( +boldsymbol{q} boldsymbol{C} ) are placed on five vertices of a regular hexagon of side ( L ) m. The magnitude of the force on the point charge of value ( -q C ) placed at the centre of the hexagon is ( N ) |
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457 | A neutral water molecule is placed in electic field ( boldsymbol{E}=mathbf{1 . 2 5} times mathbf{1 0}^{mathbf{4}} boldsymbol{N} / boldsymbol{C} . ) The work done to rotate it by ( 180^{circ} ) is ( 2.5 times ) ( 10^{-25} J . ) Find aproximate separation of center of charges. A. ( 0.625 times 10^{-9} mathrm{m} ) в. ( 0.65 times 10^{-10} mathrm{m} ) C ( .0 .75 times 10^{-10} mathrm{m} ) D. ( 0.625 times 10^{-10} m ) |
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458 | The diagram shows four charges ( boldsymbol{q}_{1}, boldsymbol{q}_{2}, boldsymbol{q}_{3} ) and ( boldsymbol{q}_{4} ) all lying in the plane of the page. The diagram also shows the dotted circle that represents the cross- section of a spherical Gaussian surface Point ( P ) is a single point on that surface Which of the charges contributes to the net electric flux through the sphere? A ( cdot q_{1} ) and ( q_{3} ) B. ( q_{2} ) and ( q_{4} ) ( mathbf{c} cdot q_{1} ) and ( q_{2} ) ( mathbf{D} cdot q_{3} ) and ( q_{4} ) E ( . q_{1}, q_{2}, q_{3}, ) and ( q_{4} ) |
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459 | The electric field outside the plates of two oppositely charged plane sheets of charge density ( sigma ) is : A ( cdot+frac{sigma}{2 varepsilon_{0}} ) В. ( -frac{sigma}{2 varepsilon_{0}} ) c. zero D. ( frac{sigma}{varepsilon_{0}} ) |
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460 | wo lutitical vedus, tach ndve d mass ( m ) and charge ( q . ) When placed in a hemispherical bowl of radius ( boldsymbol{R} ) with frictionless, non-conducting walls, the beads move and at equilibrium they are at a distance ( R ) apart (as shown in figure). Determine the charge on each bead: ( ^{mathbf{A}} cdotleft(frac{4 pi varepsilon_{0} m g R^{2}}{sqrt{3}}right)^{1 / 2} ) ( ^{mathbf{B}}left(frac{2 pi varepsilon_{0} m g R^{2}}{sqrt{3}}right)^{1 / 2} ) ( left(frac{4 pi varepsilon_{0} m g R^{2}}{sqrt{6}}right)^{1 / 2} ) ( left(frac{pi varepsilon_{0} m g R^{2}}{sqrt{3}}right)^{1 / 2} ) |
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461 | The amplitude of the electric field in a parallel beam of light of intensity ( 2.0 mathrm{Wm}^{-2} ) is: A. ( 19.4 mathrm{N} / mathrm{C} ) B. 38.8 N/C c. ( 4.85 mathrm{N} / mathrm{c} ) D. 77.9 N/C |
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462 | Who established the fact of animal electricity? A. Van de Graaff B. Count Alessandro Volta c. Gustav Robert Kirchhoff D. Hans Christian Oersted |
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463 | A charge of magnitude ( Q ) is placed at the origin. A second charge of magnitude ( 2 Q ) is placed at the position ( boldsymbol{x}=boldsymbol{d} ) along the ( mathbf{x} ) -axis. Other than infinitely far away, at what position on the ( x ) -axis will a positive test charge experience a zero net force? |
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464 | An insulating loop has one side charged positively and the other side charged negatively. An electron is placed in the middle of the loop. What would be the direction of the net force on the electron due to the charges in the ring? A. Toward the top of the loop B. Toward the right of the loop c. Toward the left of the loop D. There is no net force on the loop |
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465 | Two short electric dipoles are placed as shown. The energy of electric interaction between these dipoles will be: ( mathbf{A} ) B. ( mathbf{c} cdot frac{-2 k P_{1} P_{2} sin theta}{r^{3}} ) D. |
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466 | Two identical copper spheres carrying charges ( +Q ) and ( -9 Q ) separated by a certain distance has attractive force ( F ) If the spheres are allowed to rouch each other and moved to distance of separation ‘x’. So that the force between them becomes ( frac{4 F}{9} ). Then ( X ) is equal to A. ( d ) B. ( 2 d ) ( c cdot d / 2 ) D. ( 4 d ) |
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467 | Gaussian surface measures the electric field A. parallel to the surface area B. tangent to the surface area c. perpendicular to the surface area D. anti-parallel to the surface area |
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468 | Complete the following sentence : A rod is brought near the disc of a positively charged gold leaf electroscope. Ifthe divergence of leaves ( ldots, ) the rod is positively charged; if the divergence of leaves ……… the rod is negatively charged; if the divergence of leaves ( ldots ldots . ) the rod is uncharged. A. decreases, decreases, decreases B. increases, decreases, increases. c. increases, increases, decreases D. increases, decreases, decreases. |
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469 | Three point charges ( +boldsymbol{q},-boldsymbol{2} boldsymbol{q} ) and ( +boldsymbol{q} ) are placed at points ( (boldsymbol{x}=mathbf{0}, boldsymbol{y}=boldsymbol{a}, boldsymbol{z}= ) ( mathbf{0}),(boldsymbol{x}=mathbf{0}, boldsymbol{y}=mathbf{0}, boldsymbol{z}=mathbf{0}) ) and ( (boldsymbol{x}= ) ( boldsymbol{a}, boldsymbol{y}=mathbf{0}, boldsymbol{z}=mathbf{0}) ) respectively. The magnitude and direction of the electric dipole moment vector of this charge assembly are : A . ( sqrt{2 q a} ) along ( +y ) direction B. ( sqrt{2} q a ) along the line joining points ( (x=0, y=0, z= ) 0) and ( (x=a, y=a, z=0) ) c. ( q a ) along the line joining points ( (x=0, y=0, z= ) 0) and ( (x=a, y=a, z=0) ) D. ( sqrt{q} a ) along ( +x ) direction |
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470 | A small sphere of mass ( m ) and having charge ( q ) is suspended by a silk thread of length ( l ) in a uniform horizontal electric filed. If it stands at a distance ( x ) from the vertical line from point of suspension, then magnitude of electric field is : A. ( frac{m g}{q} ) в. ( frac{m g}{q} ) c. ( frac{m g x}{q sqrt{l^{2}-x^{2}}} ) D. ( frac{m g l}{q sqrt{x^{2}-l^{2}}} ) |
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471 | Like charges each other and unlike charges each other: A . repel, attract B. attract, repel c. repel, repel D. attract, attract |
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472 | Coulomb’s Law agrees with A. Newtons 3rd Law of Motion B. Newtons 1st Law of Motion C. Newtons 2 nd Law of Motion D. All of the above |
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473 | Six charges are placed at the vertices of a regular hexagon as shown in the figure. Find the electric field on the line passing through ( O ) and perpendicular to the plane of the figure as a function of distance ( x ) from point ( O ) A . B. 4 ( c .1 ) D. 2 |
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474 | A spherical capacitor consists of two concentric spherical conductors of inner one of radius ( R_{1} ) maintained at potential ( V_{1} ) and the outer one of radius ( boldsymbol{R}_{2} ) at potential ( boldsymbol{V}_{2} . ) The potential at a point ( p ) at a distance ( x ) from the centre ( left(R_{2}>x>R_{1}right) ) is: A ( cdot frac{V_{1}-V_{2}}{R_{2}-R_{1}}left(x-R_{1}right) ) B. ( frac{V_{1} R_{1}left(R_{2}-xright)+V_{2} R_{2}left(x-R_{1}right)}{xleft(R_{2}-R_{1}right)} ) C ( cdot V_{1}+frac{V_{2} x}{R_{2}-R_{1}} ) D. ( frac{V_{1}+V_{2}}{R_{2}+R_{1}} x ) |
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475 | toppr ( t ) Q Type your question ( mathbf{A} ) B. Diagram B ( c ) D. ( E ) |
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476 | Electric field intensity in free space at a distance ‘ ( r^{prime} ) outside the charged conducting sphere of radius ‘ ( boldsymbol{R}^{prime} ) in terms of surface charge density ‘sigma’ is : A ( cdot frac{sigma}{epsilon_{0}}left[frac{R}{r}right]^{2} ) В. ( frac{epsilon_{0}}{sigma}left[frac{R}{r}right]^{2} ) c. ( frac{R}{r}left[frac{sigma}{epsilon_{0}}right]^{2} ) D. ( frac{R}{sigma}left[frac{r}{epsilon_{0}}right]^{2} ) |
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477 | The electric field in a certain region is acting radially outward and is given by ( E=A r . A ) charge contained in a sphere of radius ‘a’ centered at the origin of the field, will be given by : A ( cdot 4 pi epsilon_{0} A a^{3} ) В ( cdot epsilon_{0} A a^{3} ) ( mathbf{c} cdot 4 pi epsilon_{0} A a^{2} ) D. ( A epsilon_{0} a^{2} ) |
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478 | A charged particle of mass ( 5 times 10^{-6} mathrm{kg} ) is held stationary in space by placing it in an electric field of strength ( 10^{6} N C^{-1} ) directed vertically downwards. The charge of the particle is ( left(boldsymbol{g}=mathbf{1 0 m} boldsymbol{s}^{-mathbf{2}}right): ) A. ( -20 times 10^{-4} mu C ) B. ( -5 times 10^{-5} mu C ) c. ( 5 times 10^{-11} mu C ) D. ( 20 times 10^{-5} mu C ) |
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479 | For which of the following dependences of drift velocity ( v_{d} ) on electric field ( mathrm{E} ), is Ohm’s law obeyed? A ( cdot v_{d} propto E ) в. ( v_{d} propto E^{2} ) c. ( v_{d} propto sqrt{E} ) D. ( v_{d} propto frac{1}{E} ) |
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480 | The point charges ( -5 n C, 10 n C ) and ( 12 n C ) are located at (0,0,0),(0,0,1) and (0,0,2) respectively. Find the total energy of the system. | 12 |

481 | Work done in turning dipole through an angle 60 is A. zero в. ( p E / 4 ) c. ( p E ) D. ( p E / 2 ) |
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482 | A sample of HCl is placed in an electric field of ( 2.5 times 10^{4} N C^{-1} . ) The dipole moment of HCl is ( 3.4 times 10^{-30} mathrm{Cm} ). Find the maximum torque that can act on a molecule. A ( cdot 7.6 times 10^{-26} mathrm{Nm} ) В. ( 4.3 times 10^{-26} mathrm{Nm} ) c. ( 6.5 times 10^{-26} mathrm{Nm} ) D. ( 8.5 times 10^{-26} mathrm{Nm} ) |
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483 | Two spheres of equal mass ( A ) and ( B ) are given ( +q ) and ( -q ) charge respectively then: A. Mass of A increases. B. Mass of B increases. C. Mass of A remains constant. D. Mass of B decreases. |
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484 | A thick shell with inner radius ( R ) and outer radius ( 3 R ) has a uniform charge density ( sigma c / m^{3} . ) It has a spherical cavity of radius ( R ) as shown in the figure. the electric field at the centre of the cavity is A . zero в. ( 2 sigma R / varepsilon_{0} ) c. ( 3 sigma R / 4 varepsilon_{0} ) D. ( 7 sigma R / 12 varepsilon_{0} ) |
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485 | Electric field inside the cavity of any conductor is A . Infinite B ( cdot vec{E}=frac{epsilon_{0}}{sigma} ) c. zero D・ ( vec{E}=K frac{sigma}{epsilon_{0}} hat{n} ) |
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486 | Four dipoles each one having magnitudes of charges ( pm mathrm{e} ) are placed inside a sphere. The total flux of ( vec{E} ) coming out of the sphere is : A. zero в. ( frac{4 e}{varepsilon_{0}} ) ( c cdot frac{8 e}{varepsilon_{0}} ) D. None of these |
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487 | A charge q is situated at the centre of a square of side d. The electric field intensity at the midpoint of a side is ( mathrm{E}_{1} ) and at one corner of the square is ( mathrm{E}_{2} ) Then, the ratio of ( E_{1} / E_{2} ) is : A . 0.5 в. 0.7 c. 1 D. |
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488 | State whether the given statement is True or False : Gauss’ law is useful for the calculation |
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489 | Gold leaf electroscope is used: A. to measure the electric charge B. to detect and test small electric charges C . to produce electric current D. to produce electric charges |
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490 | In the given figure distance of the point from A where the electric field is zero is ( mathbf{A} cdot 10 mathrm{cm} ) B. 33 cm c. ( 20 mathrm{cm} ) D. None of these |
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491 | 1 | 12 |

492 | A sphere has a charge of ( +50 C . ) The absolute potential at a point at distance of ( 10^{-12} ) m from the sphere is: (Radius of the sphere is ( left.<10^{-12} text {m }right) ) A . ( 4500 mathrm{V} ) B . ( 45 times 10^{23} mathrm{V} ) c. ( 4.5 times 10^{23} V ) D. ( 45 times 10^{24} V ) |
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493 | toppr oGın Q Type your question position ( x=12 mathrm{m} ) on the line. A proton placed at any point on the line between the two charges will experience a net force due to the two charges. The net force acting on the proton is shown as a function of position in the graph, where positive values of force represent rightward force. What is the sign of each charge, and |
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494 | In a certain region of space, the potential is given by ( boldsymbol{V}=boldsymbol{k}left[mathbf{2} boldsymbol{x}^{2}-boldsymbol{y}^{2}+boldsymbol{z}^{2}right] . ) The electric field at the point (1,1,1) has magnitude ( = ) A ( . k sqrt{6} ) в. ( 2 k sqrt{6} ) c. ( 2 sqrt{3} k ) D. ( 4 k sqrt{3} ) is |
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495 | A very long, solid insulating cylinder with radius ( R ) has a cylindrical hole with radius ( a ) bored along its entire length. The axis of the hole is a distance ( b ) from the axis of the cylinder, where ( a<b<R ) (as shown in figure). The solid material of the cylinder has a uniform has a uniform volume charge density ( rho . ) Find the magnitude and direction of the electric field inside the hole, and show that this is uniform over the entire hole. |
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496 | A point charge of value ( 10^{-7} C ) is situated at the centre of cube of ( 1 boldsymbol{m} ) side. The electric flux through its total surface area is: A. ( 113 times 10^{4} mathrm{Nm}^{2} / mathrm{C} ) в. ( 11.3 times 10^{4} mathrm{Nm}^{2} / mathrm{C} ) C. ( 1.13 times 10^{4} mathrm{Nm}^{2} / mathrm{C} ) D. none of these |
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497 | Charge is produced by friction A. Stationary B. No c. Attractive D. All |
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498 | Electric flux through a surface of area 100 ( m^{2} ) lying in the xy plane is (in ( V ) m) if ( overrightarrow{boldsymbol{E}}=hat{boldsymbol{i}}+sqrt{boldsymbol{2}} hat{boldsymbol{j}}+sqrt{boldsymbol{3}} hat{boldsymbol{k}} ) A. 100 B. 141.4 c. 173.2 D. 200 |
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499 | What are electric lines of force? State the properties of lines of force. |
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500 | An electric dipole will experience a net force when it is placed in A . a uniform electric field B. a non-uniform electric field ( c . ) both a and ( b ) D. None of these |
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501 | An electric dipole is placed in an electric field generated by a point charge. Then A. net electric force on the diploe must be zero B. net electric force on the diploe may be zero c. torque on the dipole due to the field must be zero D. torque on the dipole due to the field may be zero |
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502 | The Sl unit of electric flux is A. ( N / C ) в. ( N m / C ) c. ( N m^{2} ) D. ( N m^{2} / C ) |
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503 | State Coulomb’s law in electrostatics. | 12 |

504 | During charging by friction, A. charge is created. B. charged is destroyed. c. charge is conserved. D. None of these |
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505 | An electric dipole placed in a non- uniform electric field experiences: A. Both a torque and a net force B. Only a force but no torque C. Only a torque but no net force D. No torque and no net force |
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506 | A positive charge ( q ) at origin is moving with velocity ( v_{0} hat{j} ). Magnetic field at point ( (a,-a) ) is A. zero B. ( frac{mu_{0} q v_{0}}{16 sqrt{2} pi a^{2}} hat{k} ) c. ( frac{-mu_{0} q v_{0}}{8 sqrt{2} pi a^{2}} hat{k} ) D. ( frac{-mu_{0} q v_{0}}{4 sqrt{2} pi a^{2}} hat{k} ) |
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507 | Assertion The positive charge particle is placed in front of a spherical uncharged conductor. The number of lines of forces terminating on the sphere will be more than those emerging from it. Reason The surface charge density at a point on the sphere nearest to the point charge will be negative and maximum in magnitude compared to other points on the sphere A. Both Assertion and Reason are correct and Reason is the correct explanation for Assertion B. Both Assertion and Reason are correct but Reason is not the correct explanation for Assertion c. Assertion is correct but Reason is incorrect D. Assertion is incorrect but Reason is correct |
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508 | A point charge ( +Q ) is placed just outside an imaginary hemispherical surface of radius ( R ) as shown in the figure. Which of the following statements is/are correct? This question has multiple correct options A. The electric flux passing through the curved surface of the hemisphere is ( -frac{Q}{2_{varepsilon_{0}}}left(1-frac{1}{sqrt{2}}right) ) B. Total flux through the curved and the flat surface is ( underline{Q} ) C. The component of the electric field normal to the flat surface is constant over the surface D. The circumference of the flat surface is an equipotential |
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509 | A point dipole ( overrightarrow{boldsymbol{p}}=boldsymbol{p}_{0} hat{boldsymbol{x}} ) is kept at the origin. The potential and electrical field due to this dipole on the y-axis at a distance ( d ) are, respectively: (Take ( V=0 text { at infinity }) ) A ( cdot frac{|vec{p}|}{4 pi varepsilon_{d} d^{2}}, frac{-vec{p}}{4 pi varepsilon_{0} d^{3}} ) В. ( 0, frac{vec{p}}{4 pi varepsilon_{0} d^{3}} ) c. ( frac{|vec{p}|}{4 pi varepsilon_{0} d^{2}}, frac{vec{p}}{4 pi varepsilon_{0} d^{3}} ) D. ( _{0,} frac{-vec{p}}{4 pi varepsilon_{0} d^{3}} ) |
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510 | What is electric field intensity at any point on the axis of a charged rod of length ‘ ( L ) ‘ and linear charge density’ ( lambda ) ‘? The point is separated from the nearer end by a. |
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511 | Suld and mass ( 1 mathrm{kg} ) are placed (fixed) symmetrically about a movable central charge of magnitude ( 5 times ) ( 10^{-5} C ) and mass 0.5 kg as shown. The charge at ( P_{1} ) is removed. The acceleration of the central charge is: ( left[text { Given } boldsymbol{O} boldsymbol{P}_{1}=boldsymbol{O} boldsymbol{P}_{2}=boldsymbol{O} boldsymbol{P}_{3}=boldsymbol{O} boldsymbol{P}_{4}=right. ) ( left.O P_{5} 1 m ; frac{1}{4 pi varepsilon_{0}}=9 times 10^{9} text { in SI units }right] ) A ( .9 m s^{-2} ) upwards B. ( 9 m s^{-2} ) downwards C ( .4 .5 mathrm{m} mathrm{s}^{-2} ) upwards D. ( 4.5 m s^{-2} ) downwards |
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512 | Given a uniform electric field ( overrightarrow{boldsymbol{E}}=mathbf{5} times ) ( 10^{3} hat{i} N / C, ) find the flux of this field through a square of ( 10 mathrm{cm} ) on a side whose plane is parallel to the ( y ) -z plane. What could be the flux through the same square if the plane makes ( 30^{circ} ) angle with the ( x ) -axis? |
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513 | When a test charge is brought in from infinity along the perpendicular bisector of an electric dipole, the work done is A. positive B. zero c. Negative D. None of theses |
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514 | An electric field ( vec{E}-vec{i} A x ) exists in the space, where ( A=V / m^{2} ). take the potential at ( (10 m, 20 m) ) to be zero. Find the potential at the origin. |
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515 | Q Type your question- along ( x ) -axis. The equilibrium of a positive test charge placed at the point 0 midway between them is stable for displacements along the ( x ) -axis. Reason: Force on test charge is zero. A. If both Assertion arid Reason are correct and Reason is the correct explanation of Assertion. B. If both Assertion and Reason are correct, but Reason is not the correct explanation of Assertion, C. If Assertion is correct but Reason is incorrect. D. If Assertion is incorrect but Reason is correct |
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516 | If the potential at each point on a conductor is same to each other, then A. Electric lines of force may begin or end on the same conductor B. No electric lines of force may begin or end on the same conductor c. The electric field inside the conductor may be non-zero D. None of the above |
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517 | Three infinitely long charge sheets are placed as shown in the figure. The electric field at point ( P ) is going to be ( A ) B. ( -frac{2 sigma}{varepsilon_{0}} ) ( c ) D. |
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518 | An infinite large plate has a net positive charge. When referring to the electric field just as it is coming out of the plate: A. Some of the electric field is perpendicular to the plate B. All of the electric field is perpendicular to the plate C. None of the electric field is perpendicular to the plate D. There is no electric field coming out of the plate |
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519 | When a glass rod is rubbed with silk A. Negative charge is produced on silk but not charge on the glass rod B. Equal but opposite charge are produced on the both C. Equal and similar charges are produced on the both D. Positive charge is produced on the glass rod but no charge on the silk |
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520 | Two electric field lines cannot cross each other. Also, they cannot form closed loops. Give reasons. |
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521 | The best conductor of heat is A. Silver B. Bronze c. Aluminium D. copper |
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522 | If a body acquires electric charge temporarily under the influence of charged body, then the process is called: A. conduction B. induction c. radiation D. dispersion |
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523 | If ( oint_{s} overrightarrow{boldsymbol{E}} cdot overrightarrow{boldsymbol{d}} boldsymbol{s}=boldsymbol{0} ) over surface, then A. the electric field inside the surface and on it is zero B. the electric field inside the surface is necessarily uniform C . all charges must necessarily be outside the surface D. all of these |
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524 | Assertion Sometime, a crackling sound is heard while taking off sweater during winters. Reason This is due to static electric charges. A. Both Assertion and Reason are correct and Reason is the correct explanation for Assertion B. Both Assertion and Reason are correct but Reason is not the correct explanation for Assertion C. Assertion is correct but Reason is incorrect D. Both Assertion and Reason are incorrect |
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525 | Uniform electric field of intensity 5 volt/m acts parallel to x axis. A charge of ( 2 C ) is moved from to ( A(1,1), ) to ( B(2,1) ) and finally to ( mathrm{D}(3, mathrm{C}) ) in this field.Work done in this process is : A. 60 joule B. 40 joule c. 30 joule D. zero |
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526 | Metals are good conductors because A. Outer electrons are strongly bound to the atom. B. Outer electrons are loosely bound to the atom. C. Inner electrons are loosely bound to the atoms. D. Protons can detach from the nucleus and conduct electricity. |
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527 | Three concentric spherical metallic shells ( A, B ) and ( C ) of radii ( a, b ) and ( c(a<b<c) ) have charge densities ( sigma,-sigma ) and ( sigma ) respectively. If the shells ( A ) and ( C ) are at same potential, then the relation between ( a, b ) and ( c ) is A ( . a+b+c=0 ) B . ( a+c=b ) c. ( a+b=c ) D. ( a=b+c ) |
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528 | Figure given below shows three possibilities for the potential at two points, ( A ) and ( B ) In each case, the same positive charge is moved from ( A ) to ( B ). The work done in the positive case will be maximum is:- begin{tabular}{|cc|cc|cc|} hline ( mathbf{A} ) & ( mathbf{B} ) & ( mathbf{A} ) & ( mathbf{B} ) & ( mathbf{A} ) & ( mathbf{B} ) \ ( mathbf{1 5 0} mathbf{~ V} ) & ( mathbf{5 0} mathbf{~ V} ) & ( mathbf{4 0} ) & ( mathbf{0} ) & ( mathbf{- 4 0} mathbf{V} ) & ( -mathbf{2 0} mathbf{V} ) & ( mathbf{- 8 0} mathbf{~ V} ) \ ( mathbf{~ C a s e – 1} ) & & ( mathbf{C a s e -} mathbf{2} ) & & ( mathbf{C a s e}-mathbf{3} ) \ hline end{tabular} A. case B. Case 2 c. case 3 D. In all three cases |
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529 | A neutral conducting spherical shell is kept near a charge ( q ) as shown. The potential at point ( P ) due to the induced charges is : ( A cdot frac{k q}{r} ) в. ( frac{k q}{r^{prime} q} ) с. ( frac{k q}{r}-frac{k q}{r^{prime}} ) D. ( frac{k q}{C P} ) |
12 |

530 | The inside of the bottle of a gold-leaf electroscope is occasionally evacuated A. to prevent the charge on the terminal from leaking of through ionisation of the air B. to leak off the charge on the terminal through ionisation of the air C. to prevent the charge on the terminal from leaking off through induction. D. None of these |
12 |

531 | A charge ( Q ) is placed at each of the opposite corners of a sequare. A charge ( q ) is placed at each of the other two corners. If the net electric force on ( Q ) is zero, then ( Q / q ) equals: A . -1 B. 1 c. ( -frac{1}{2} ) D. ( -2 sqrt{2} ) |
12 |

532 | Electric field at a distance ( x ) from the origin its given as ( boldsymbol{E}=frac{mathbf{1 0 0 N}-boldsymbol{m}^{2} / boldsymbol{C}}{boldsymbol{x}^{2}} ) Then potential difference between the points situated at ( x=10 m ) and ( x= ) ( 20 m ) is: ( A cdot 5 V ) B. ( 10 V ) ( c .15 V ) D. ( 4 V ) |
12 |

533 | In general, metals have very low: A. Boiling Point B. Freezing Point c. Melting Point D. Specific Heat Capacity |
12 |

534 | A particle of mass ( mathrm{m} ) and charge ( -mathrm{q} ) moves diametrically through a uniformly charged sphere of radius R with total charge ( Q ). The angular frequency of the particle’s simple harmonic motion, if its amplitude ( <mathrm{R} ), is given by : A. ( sqrt{frac{1}{4 pi varepsilon_{0}} frac{q Q}{m R}} ) в. ( sqrt{frac{1}{4 pi varepsilon_{0}} frac{q Q}{m R^{2}}} ) c. ( sqrt{frac{1}{4 pi varepsilon_{0}} frac{q Q}{m R^{3}}} ) D. ( sqrt{frac{1}{4 pi varepsilon_{0}} frac{m}{m Q}} ) |
12 |

535 | topp Q Type your question microcoulombs, +2 microcoulombs and -2 microcoulombs. Find out the direction of the net electric force acting on the +1 microcoulombs charge. ( A ) B. ( c ) ( D ) E |
12 |

536 | When a glass rod is rubbed with silk, both become charged due to: A. migration of protons B. exchange of electrons and protons c. migration of electrons D. migration of neutrons |
12 |

537 | The electric field for ( r>R_{2} ) is given by ( boldsymbol{E}=frac{1}{boldsymbol{X} boldsymbol{pi} varepsilon_{0}} frac{Q}{r^{2}} . ) Find ( mathbf{X} ? ) |
12 |

538 | A conducting sphere is enclosed by a hollow conducting shell. Initially the inner sphere has a charge ( Q ) while the outer one is uncharged. The potential difference between the two spherical surface is found to be ( V ). Later on the outer shell is given a charge ( -4 Q ). The new potential difference between the two surface is: A. ( V ) B. ( -V ) c. ( -2 V ) D. ( 2 V ) |
12 |

539 | A charged gold leaf electroscope has its leaves apart by certain amount having enclosed air. When the electroscope is subjected to X-rays, then the leaves A. Further dilate B. Start oscillating c. collapse D. Remain unaltered |
12 |

540 | Charges always reside of the charged conducting object. ( A ). in the bulk B. on the surface c. Both A and B D. Neither A nor B |
12 |

541 | A negative point charge ( 2 q ) and ( a ) positive charge ( q ) are fixed at a distance ( l ) apart. Where should a positive test charge ( Q ) be placed on the line connecting the charge for it to be in equilibrium? What is the nature of the equilibrium with respect to longitudinal motions? |
12 |

542 | A suitable unit for expressing the strength of electric field is : A. v/C B. ( mathrm{c} / mathrm{m} ) c. N/C D. c/N |
12 |

543 | The mutual force of repulsion between two point charges kept a fixed distance apart is ( 9 times 10^{-5} N ) when in vacuum and ( 4 times 10^{-5} N ) when placed in a dielectric medium. What is the value of dielectric constant of the medium? |
12 |

544 | toppr Q Type your question volume. I ne cyıınaer nas a cnarge per unit length of ( lambda ) A Gaussian surface is imagined that is |
12 |

545 | Four equal charges ( Q ) are placed at the removing a charge ( -Q ) from its centr A . zero B. ( frac{sqrt{2} mathrm{Q}^{2}}{4 pi epsilon_{0} mathrm{a}} ) c. ( frac{sqrt{2} mathrm{Q}^{2}}{pi epsilon_{0} mathrm{a}} ) D. ( frac{Q^{2}}{2 pi epsilon_{0} a} ) |
12 |

546 | In Coulomb’s law, the constant of proportionality K has the units ( N m^{2} / C^{2} ) then the magnitude of ( mathrm{K} ) in air is : A ( 9 times 10^{5} ) ( ^{5} ) B. ( 9 times 10^{9} ) ( mathrm{c} cdot 9 times 10^{3} ) D. none of these |
12 |

547 | A charge is placed at the edge of a cube of each side ‘ ( a^{prime} ). Calculate the electric flux through each face of the cube. ( A cdot frac{Q}{40} ) B. ( frac{Q}{240} ) ( c cdot frac{Q}{20} ) D. ( frac{Q}{15 varepsilon_{0}} ) |
12 |

548 | The electric field at a point due to an electric dipole, or an axis inclined at an angle ( thetaleft(<90^{circ}right) ) to the dipole axis, is perpendicular to the dipole axis, if the angle ( boldsymbol{theta} ) is A ( cdot tan ^{-1} ) B. ( tan ^{-1}left(frac{1}{2}right) ) ( mathbf{c} cdot tan ^{-1}(sqrt{2}) ) D ( cdot tan ^{-1}left(frac{1}{sqrt{2}}right) ) |
12 |

549 | If electric field between plates of a parallel plate capacitor is ( 2 N C^{-1} ) and charge on two plates are ( 10 mathrm{C} ) and ( 3 mathrm{C} ) then force on one of the plates is A. 20 N B. 30 N c. ( frac{60}{7} N ) D. ( frac{7}{2} N ) |
12 |

550 | An electric dipole ( dipole moment p) is placed at a radial distance ( r>>a ) ( Where a is dipole length) from an infinite line of charge having linear charge density ( +lambda ) dipole moment vector is aligned along the radial vector ( vec{r} ) force experienced by the dipole is:- A ( cdot frac{lambda p}{2 pi varepsilon_{o} r^{2}}, ) attractive B. ( frac{lambda p}{2 pi varepsilon_{o} r^{3}}, ) attractive C ( cdot frac{lambda p}{2 pi varepsilon_{o} r^{2}}, ) repulsive D. ( frac{lambda p}{2 pi varepsilon_{o} r^{3}}, ) repulsive |
12 |

551 | The dimensional formula for electric flux density is given by A ( cdotleft[M L T^{-3} A-1right] ) B . ( left[M L T^{3} A-1right] ) c. ( left[M L T^{-3} A 1right] ) D. ( left[M L T^{3} A 1right] ) |
12 |

552 | Derive an expression for electric potential at a point due to an electric dipole. Discuss the special cases. |
12 |

553 | At all points inside a uniform spherical shell – A. gravitational intensity and gravitational potential both are zero B. gravitational intensity and gravitational potential both are non- zero C . gravitational intensity is non- zero and gravitational potential both are zero D. gravitational intensity is zero and gravitational potential both are non-zero |
12 |

554 | Two charged particles moving with velocities ( v_{1} ) and ( v_{2} ) have some separation between them. The ratio of magnetic force to the Colombian force between them is (c is speed of light) A. ( frac{v_{1} v_{2}}{c^{2}} ) в. ( frac{c^{2}}{v_{i} v_{2}} ) c. ( frac{c}{v_{1}} ) D. ( frac{c}{v_{2}} ) |
12 |

555 | The total probability of finding a particles in space under normalized condition according to quantum mechanics is A. zero B. Infinity c. one D. Uncertain |
12 |

556 | A charge q is enclosed as shown in all figure, the electric flux is (i) (iii) A. maximum in (i) B. maximum in (ii) c. maximum in (iii) D. equal in all |
12 |

557 | In the figure, there are four arcs carrying positive and negative charges. All of them have same charge density ( lambda ) Pick incorrect statement(s). This question has multiple correct options A. The net dipole moment for the given charge distribution is ( (4 sqrt{5}) lambda R^{2} ) B. The resultant electric field at the center is zero C. If a uniform ( vec{E} ) is switched on perpendicular to the plane, charge distribution starts rotating about ( X ) -axis D. Potential at the centre of the given charge distribution is non-zero |
12 |

558 | Three charges each of magnitude q are placed at the corners of an equilateral triangle, the electrostatic force on the charge placed at the center is(each side of triangle is ( L ) ) A. Zero ( ^{mathrm{B}} frac{1}{4 pi varepsilon_{0}} frac{q^{2}}{L^{2}} ) c. ( frac{1}{4 pi varepsilon_{0}} frac{3 q^{2}}{L^{2}} ) ( D ) |
12 |

559 | Find the initial acceleration of the rod | 12 |

560 | State Coulomb’s law of force in electrostatics. |
12 |

561 | The electric charges are distributed in a small volume. The flux of the electric field through a spherical surface of radius ( 10 mathrm{cm} ) surrounding the total charge is ( 20 V ) m. The flux over a concentric sphere of radius ( 20 mathrm{cm} ) will be A ( .20 mathrm{V} . mathrm{m} ) B. ( 25 V . m ) c. ( 40 V . m ) D. 200V.m |
12 |

562 | Write an expression (derivation not required) for intensity of electric field of an electric dipole, in terms of its length (2a), dipole moment ( ( p ) ) and distance ( (r) ) for: (1) Axial position. (2) Broad side position. |
12 |

563 | How many electron will constitute ( 32 mathrm{C} ) of charge? A ( .2 times 10^{19} ) B . ( 2 times 10^{18} ) ( mathrm{c} cdot 2 times 10^{17} ) D. ( 2 times 10^{20} ) |
12 |

564 | A copper ball of density ( p_{c} ) and diameter d is immersed in oil of density ( p_{o} . ) What charge should be present on the ball, so that it could be suspended in the oil, if a homogeneous electric field E is applied vertically upward? ( ^{mathrm{A}} cdot_{mathrm{Q}}=frac{pi d^{2}left(p_{c}-p_{0}right) g}{6 E} ) в. ( quad Q=frac{pi d^{3}left(p_{c}-p_{0}right) g}{6 E} ) c. ( _{Q}=frac{pi d^{3}left(p_{c}-p_{0}right) g}{E} ) D. ( _{Q}=frac{pi d^{2}left(p_{c}-p_{0}right) g}{2 E} ) |
12 |

565 | length ( L, ) pivoted at its centre and balanced with a weight ( W ) at a distance ( x ) from the left end is shown in the figure. Two positive point charges q and ( 2 q ) are attached at the left and right ends of the rod. A distance ( h ) directly below each of these charges is a fixed positive charge ( Q ). The distance ( x^{prime} ) in terms of ( q, Q, L ) and ( W ) is (Assume than ( L>>h ) and neglect masses of the point charges) A. ( ^{mathbf{B}} cdot frac{4 q Q L+varepsilon_{0} h^{2} W L}{8 pi h^{2} W} ) ( ^{mathbf{C}} cdot frac{q Q L+4 pi varepsilon_{0} h^{2} W L}{8 pi varepsilon_{0} h^{2} W} ) D. ( frac{q Q L+varepsilon_{0} h^{2} W L}{h^{2} W} ) |
12 |

566 | The force experienced on an electric charge of ( 10 mathrm{C} ) placed at a point in the electric field is 50 N. The strength of the electric field at the point is A ( cdot 25 mathrm{N} mathrm{C}^{-1} ) B. 5 N ( c^{-1} ) c. ( 10 mathrm{N} mathrm{c}^{-1} ) D. 30 N C ( ^{-1} ) |
12 |

567 | How many electrons make up a charge of ( 20 mu C ? ) A ( cdot 1.25 times 10^{14} ) B. ( 2.23 times 10^{14} ) c. ( 3.25 times 10^{14} ) D. ( 5.25 times 10^{14} ) |
12 |

568 | The outermost electrons are and are called conduction electrons: A. not free to move in the atom B. bound to the protons c. static D. able to go to nearby atoms |
12 |

569 | An electric dipole of moment ( p ) is lying along a uniform electric field ( boldsymbol{E} ). The work done in rotating the dipole by ( 90^{circ} ) is: A ( . p E ) B . ( sqrt{2} p E ) c. ( frac{p E}{2} ) D. ( 2 p E ) |
12 |

570 | What is meant by term Quantization of of charge? | 12 |

571 | Two identical particles each of mass ( M ) and charge ( Q ) are placed a certain distance part. If they are in equilibrium under mutual gravitational and electric force then calculate the order of ( frac{Q}{M} ) in SI units. |
12 |

572 | An electric dipole is situated in an electric field of uniform intensity whose dipole moment is p and moment of inertia is I. if the dipole is displaced then the angular frequency of its oscillation is A ( cdotleft(frac{p E}{I}right)^{1 / 2} ) B. ( left(frac{p E}{I}right)^{3 / 2} ) ( ^{mathrm{c}} cdotleft(frac{I}{p E}right)^{1 / 2} ) D. ( left(frac{p}{I E}right)^{1 / 2} ) |
12 |

573 | NaCl molecule is bound due to the electric force between the sodium and the chlorine ions when one electron of sodium is transferred to chlorine. Taking the separation between the ions to be ( 2.75 times 10^{-8} mathrm{cm}, ) find the force of |
12 |

574 | From below which of them are used in electrostatic experiments and demonstrations? A. conductors B. Insulators c. Semi conductors D. None |
12 |

575 | toppr Q Type your question- rate. In that case, which of the following graphs, drawn schematically, correctly shows the variation of the induced electric field ( boldsymbol{E}(boldsymbol{r}) ) ? ( A ) B. ( c ) ( D ) |
12 |

576 | An electric dipole is placed in a non- uniform electric field, then A. The resultant force acting on the dipole is always zero B. Torque acting on it may be zero C. The resultant force acting on the dipole may be zero D. Torque acting on it is always zero |
12 |

577 | A point charge ( Q ) is placed at the centre of a circular wire of radius ( boldsymbol{R} ) having charge q. The force of electrostatic interaction between point charge and the wire is: ( A ) в. ( frac{q}{4 pi varepsilon_{R}} ) c. zero D. none of thes |
12 |

578 | instrument is used to find the quantity of electricity of different bodies. |
12 |

579 | A charged particle initially at rest is kept in an electric field (choose the most appropriate option) A. will always move perpendicular to the line of force. B. will always move along the line of force in the direction of the field. C. will always move along the line of force opposite to the direction of the field. D. will always move along the line of force in the direction of the field or opposite to the direction of the field depending on the nature of the charge. |
12 |

580 | If the charge ( +Q ) is now at the centre of a cube of side ( 2 l ), what is the total flux emerging from all the six faces of the closed surface? A ( cdot frac{Q}{epsilon_{0}} ) в. ( frac{Q}{2 epsilon_{0}} ) c. ( frac{Q}{4 epsilon_{0}} ) D. ( frac{Q}{6 epsilon_{0}} ) |
12 |

581 | Across the surface of a charged conductor, This question has multiple correct options |
12 |

582 | A rod ( A B ) of mass ( m ) and length ( l ) is positively charged with linear charge density ( lambda mathrm{C} / mathrm{m} ). It is pivoted at end ( mathrm{A} ) and is hanging freely. If a horizontal electric field ( boldsymbol{E} ) is switched on in the region, find the angular acceleration of the rod with which it starts A ( cdot frac{E lambda}{2 m} ) в. ( frac{3 E lambda}{2 m} ) c. ( frac{3 E lambda}{m} ) D. zero |
12 |

583 | The electric field at a point is A. always continuous B. continuous if there is no charge at that point C. discontinuous if there is a charge at that point D. both (b) and (c) are correct |
12 |

584 | A charged particle of radius ( 5 times 10^{-7} mathrm{m} ) is loacted in a horizontal electric field of intensity ( 6.28 times 10^{5} V m^{-1} . ) The surrounding medium has the coefficient of viscosity ( boldsymbol{eta}=mathbf{1 . 6} times ) ( 10^{5} N s m^{-2} . ) The particle starts moving under the effect of electric field and finally attains a uniform horizontal speed of ( 0.02 m s^{-1} . ) Find the number of electrons on it : (Assume gravity free space) A . ( 3 times 10^{11} ) в. ( 6 times 10^{1} ) ( mathbf{c} cdot 9 times 10^{11} ) D. ( 1 times 10^{11} ) |
12 |

585 | The relation connecting the energy and distance ( r ) between dipole and induced dipole is : ( mathbf{A} cdot U propto r ) B. ( U propto r^{2} ) c. ( U propto r^{-6} ) D. ( U propto r^{6} ) |
12 |

586 | Find the magnitude of the electric field strength as a function of the distance ( r ) both inside and outside the ball | 12 |

587 | A metallic spherical shell has an inner radius ( boldsymbol{R}_{1} ) and outer radius ( boldsymbol{R}_{2} . ) A charge is placed at the centre of the spherical cavity. The surface charge density on the outer surface is A ( cdot frac{-q}{4 pi R_{1}^{2}} ) В. ( frac{q}{4 pi R_{2}^{2}} ) c. ( frac{q^{2}}{4 pi R_{1}^{2}} ) D. ( frac{2 q}{4 pi R_{2}^{2}} ) |
12 |

588 | What is the charge per unit area in ( C / m^{2}, ) of an infinite plane sheet of charge if the electric field produced by the sheet of charge has magnitude 3.0 N/C? |
12 |

589 | A sphere of radius ( mathrm{R} ) has a uniform volume charge density ( rho . ) The magnitude of electric field at a distance from the centre of the sphere, where ( boldsymbol{r}>boldsymbol{R}, ) is? A ( cdot frac{rho}{4 pi varepsilon_{0} r^{2}} ) B. ( frac{rho R^{2}}{varepsilon_{0} r^{2}} ) C ( cdot frac{rho R^{3}}{varepsilon_{0} r^{2}} ) D ( cdot frac{rho R^{3}}{3 varepsilon_{0} r^{2}} ) E ( cdot frac{rho R^{2}}{4 varepsilon_{0} r^{2}} ) |
12 |

590 | An electric dipole with dipole moment ( overrightarrow{boldsymbol{p}}=(3 i+4 j) times 10^{-30} C-m ) is placed in an electric field ( overrightarrow{boldsymbol{E}}=mathbf{4 0 0 0 hat { boldsymbol { i } }}(boldsymbol{N} / boldsymbol{C}) ) An external agent turns the dipole and its dipole moment becomes ( (-4 hat{mathbf{i}}+ ) ( mathbf{3} hat{boldsymbol{j}}) times mathbf{1 0}^{-mathbf{3 0}} boldsymbol{C}-boldsymbol{m} . ) The work done by the external agent is equal to: A ( cdot 4 times 10^{-27} J ) в. ( -4 times 10^{-27} mathrm{J} ) c. ( 2.8 times 10^{-26} J ) D. ( -2.8 times 10^{-26} J ) |
12 |

591 | The most common type of electroscope is A. Gold leaf electroscope B. Elongated electroscope c. swipe electroscope D. None |
12 |

592 | Cause of positive charge on a body is an excess of electrons. A . True B. False |
12 |

593 | When plastic comb is rubbed against dry hair, the plastic comb becomes negative and dry hair becomes positive A. True B. False c. Ambiguous D. Data insufficient |
12 |

594 | A charge ( Q ) is distributed over two concentric hollow spheres of radii r and ( R(>r) ) such that the surface charge densities are equal. Find the potential at the common centre, A ( cdot frac{Q}{4 pi varepsilon_{0}}left(frac{R-r}{R^{2}+r^{2}}right) ) в. ( frac{Q}{4 pi varepsilon_{0}}left(frac{R+r}{R^{2}+r^{2}}right) ) c. ( frac{Q}{4 pi varepsilon_{0}}left(frac{-R+r}{R^{2}+r^{2}}right) ) D. |
12 |

595 | ( frac{4}{25} ) Coulomb of charge contains electrons: ( mathbf{A} cdot 10^{15} ) B . ( 10^{18} ) ( mathbf{c} cdot 10^{20} ) D. None of these |
12 |

596 | Find the dimensions of ( G varepsilon_{0} .(G= ) Universal Gravitational constant ( , varepsilon_{0}= ) permittivity in vacuum) |
12 |

597 | Four point charges ( boldsymbol{q}_{boldsymbol{A}}=boldsymbol{2 mu C}, boldsymbol{q}_{boldsymbol{B}}= ) ( -5 mu C, q_{C}=2 mu C, ) and ( q_{D}=-5 mu C ) are located at the corners of a square ( A B C D ) of side ( 10 mathrm{cm} . ) What is the force on a charge of ( 1 mu C ) placed at the centre of the square? |
12 |

598 | A point charge ( Q ) is located on the axis of a disc of radius ( R ) at a distance ( b ) from the plane of the disc (figure). Show that if one-fourth of the electric flux from the charge passes through the disc, then ( R=sqrt{3} b ) |
12 |

599 | Two equal negative charges are fixed at the points ( (0, pm a) ) on the ( y ) -axis. ( A ) positive charge ( Q ) is released from rest at the points ( (2 a, 0) ) on the ( x ) -axis. The charge ( Q ) will : A. execute simple harmonic motion about the origin B. move to the origin ad remain at rest c. move to infinity D. execute oscillatory but not simple harmonic motion |
12 |

600 | An electric charge produces an electric intensity of ( 500 N / C ) at a point in air. If the air is replaced by a medium of dielectric constant ( 2.5, ) then the intensity of the electric field due to the same charge at the same point will be: A ( .100 N / C ) в. ( 150 N / C ) c. ( 200 N / C ) D. ( 300 N / C ) |
12 |

601 | A charge ( Q ) is kept at the corner of a cube. Electric flux passing through one of those faces not touches that charge is:- ( ^{A} cdot frac{Q}{24 epsilon_{0}} ) в. ( frac{Q}{3 epsilon_{0}} ) c. ( frac{Q}{8 epsilon_{0}} ) D. ( frac{Q}{6 epsilon_{0}} ) |
12 |

602 | A coin is dipped in the molten wax in a glass tube. When we heat the upper part of the glass tube, the wax around the coil will not melt because: A. Wax has a very high melting point B. Wax is a good conductor of heat c. Glass is a good conductor of heat D. Wax or glass are bad conductors |
12 |

603 | Two charge of ( +25 times 10^{-9} mathrm{C} ) and ( -25 times 10^{-9} mathrm{C} ) are placed ( 6 mathrm{m} ) apart. Find the electric field intensity ratio at point ( 4 mathrm{m} ) from the centre of the electric dipole (i) on axial line (ii) on equatorial line |
12 |

604 | The figure shows a square loop[ of resistance ( 1 Omega ) side ( 1 m ) being moved towards right at a constant speed of 1 ( m / s ). The front edge enters the ( 3 m ) wide magnetic field ( (B=1 T) ) at ( t=0 ) draw the graph of current induced in the loop as time passes. (Take the anticlockwise direction of current as positive) [ begin{array}{l} x times x times x times \ x times times times times times \ times times times times times times \ times times times times times times \ times times times times times times end{array} ] |
12 |

605 | A thin rod placed long ( x ) -axis from ( x=-a ) to ( x=+a, ) the rod carries a change uniformly distributed along its length with linear charge density ( lambda ). The potential at the point ( P(2 a, 0,0) ) will be A ( cdot frac{lambda}{pi epsilon_{0}} operatorname{In} 3 ) в. ( frac{lambda}{4 pi epsilon_{0}} ) In 2 c. ( frac{lambda}{4 pi epsilon_{0}} ) In 3 D. ( frac{lambda}{pi epsilon_{0}} ) In 2 |
12 |

606 | A molecule of a substance has a permanent electric dipole moment of magnitude ( 10^{-30} mathrm{cm} . ) A mole of this substance is polarised by applying a strong electrostatic field of magnitude ( 10^{7} V m^{-1} . ) The direction of field is changed by an angle ( 60^{circ} . ) The heat released by the substance in aligning its dipole along the new direction of the field is A. -6.5 в. ( -3 . ) ( c .3 J ) D. 65 |
12 |

607 | Electric charge ( Q, Q ) and ( -2 Q ) respectively are place at the three corner of an equilateral triangle of side a. Magnitude of the electric dipole moment of the system is: |
12 |

608 | An electron and a photon each have a wave length 1 nm. Find the energy pf the photon. |
12 |

609 | Two identical small equally charged conducting balls are suspended from long threads secured at one point. The charges and masses of the balls are such that they are in equilibrium when the distance between them is a (the length of thread ( L>> ) a). Then one of the balls is discharged. What will be the distance ( b(b<<L) ) between the balls when equilibrium is restored? |
12 |

610 | A charged body is brought near an uncharged gold leaf electroscope. What will be your observation if the body is charged? A. leaves will diverge B. leaves will converge c. leaves will remain unaffected D. none |
12 |

611 | Assertion If a point charge ( q ) is placed in front of an infinite grounded conducting plane surface, the point charge will experience a force. Reason This force is due to the induced charge on the conducting surface which is at zero potential. A. Both Assertion and Reason are correct and Reason is the correct explanation for Assertion B. Both Assertion and Reason are correct but Reason is not the correct explanation for Assertion C. Assertion is correct but Reason is incorrect D. Both Assertion and Reason are incorrect |
12 |

612 | Two charges of ( -2 Q ) and ( Q ) are located at points ( (a, 0) ) and ( (4 a, 0) ) respectively. What is the electric flux through a sphere of radius ( 3 a ) centred at the origin? A ( cdot frac{Q}{epsilon_{0}} ) в. ( frac{-Q}{epsilon_{0}} ) c. ( frac{-2 Q}{epsilon_{0}} ) D. ( frac{3 Q}{epsilon_{0}} ) |
12 |

613 | State whether true or false: Alcohol and ether are conducting liquids of electricity. A. True B. False |
12 |

614 | An electron at rest has a charge of ( 1.6 times 10^{-19} C . ) It starts moving with a velocity ( boldsymbol{v}=boldsymbol{c} / 2, ) where ( boldsymbol{c} ) is the speed of light, then the value the new charge on it is ( mathbf{A} cdot 1.6 times 10^{-19} ) Coulomb B. ( _{1.6} times 10^{-19} sqrt{1-left(frac{1}{2}right)^{2}} ) Coulomb c. ( _{1.6} times 10^{-19} sqrt{left(frac{1}{2}right)^{2}-1 text { Coulomb }} ) ( frac{1.6 times 10^{-19}}{sqrt{1-left(frac{1}{2}right)^{2}}} ) Coulom |
12 |

615 | A large hollow metal sphere of radius has a small opening at the top through which drops of mercury each of radius ( r ) and charged to a potential V fall into the sphere and the potential becomes ( V^{prime} ) after ( mathrm{N} ) drops fall into it. Then: A. ( mathrm{V}^{prime}<mathrm{V} ) for any value of ( mathrm{N} ) B. ( mathrm{V}^{prime}=mathrm{V} ) for ( mathrm{N}=1 ) c. ( mathrm{v}^{prime}=mathrm{v} ) for ( mathrm{N}=frac{mathrm{R}}{mathrm{r}} ) D |
12 |

616 | State the effect on the divergence of the leaves of a gold leaf electroscope on bringing a negatively charged rod near it if the electroscope is positively charged: A. Divergence decreases B. Divergence increases c. Divergence remains same D. can’t say |
12 |

617 | A charge ( Q ) is placed on to two opposite corner of a square. A charge q is placed at each of other two corners. Given that resultant electric force on ( Q ) is zero, then ( Q ) is equal to : A ( cdot(2 sqrt{2}) / q ) B . ( -q /(2 sqrt{2}) ) c. ( (2 sqrt{2}) q ) D. ( (-2 sqrt{2}) q ) |
12 |

618 | A free charge is placed at a point at which there is no charge, then A. The charge must be in stable equilibrium B. The charge may be in stable equilibrium C. The charge must not be in stable equilibrium D. The potential energy of the charge is minimum |
12 |

619 | 0 | 12 |

620 | State whether the given statement is True or False :
When silk is rubbed with glass, the silk gets positively charged. |
12 |

621 | Consider the charges ( boldsymbol{q}, boldsymbol{q} ) and ( -boldsymbol{q} ) placed at the vertices of an equilateral triangle of each side ( l ). The sum of forces acting on each charge is A ( cdot frac{q^{2}}{4 sqrt{2} pi varepsilon_{0} l^{2}} ) в. ( frac{-q^{2}}{4 pi varepsilon_{0} l^{2}} ) c. ( frac{q^{2}}{4 pi varepsilon_{0} l^{2}} ) D. zero |
12 |

622 | Choose the correct statement from the following This question has multiple correct options A. Electric lines of force never cross each other B. Electric lines of force end at a positive C. The electric field charge inside a conductor are infinity D. Lines of electric field point towards regions of lower potential |
12 |

623 | Positive and negative point charges of equal magnitude are kept at ( left(0,0 frac{a}{2}right) ) and ( left(0,0 frac{-a}{2}right), ) respectively. The work done by the electric field when another positive point charge is moved from ( (-a, 0,0) ) to ( (0, a, 0) ) is: A. positive B. negative c. zero D. depends on the path connecting the initial and final positions |
12 |

624 | what is the net charge on a conducting sphere of radius ( 19 mathrm{cm} ) ? given that the electric field ( 15 mathrm{cm} ) from the centre of the sphere is equal to ( 3 times 10^{3} mathrm{N} / mathrm{C} ) and is directed inward A. ( -7.5 times 10^{-5} mathrm{C} ) в. ( -7.5 times 10^{-9} mathrm{C} ) c. ( 7.5 times 10^{-5} C ) D. ( 7.5 times 10^{-9} C ) |
12 |

625 | Two identical particles of mass ( m ) carry charge ( Q ) each. Initially one is at rest on a smooth horizontal plane and the other is projected along the plane directly towards the first from a large distance with an initial speed ( V ). Find the closest distance of approach. |
12 |

626 | The density of field lines surrounding any given object reveal information about the A. the nature of charge on the source charge. B. the quantity of charge on the source charge. c. both A and B D. it reveals no information |
12 |

627 | In a certain region of space, electric field is along z-direction throughout The magnitude of electric field is, however, not constant but increases uniformly along the positive z-direction, at the rate of ( 10^{5} N C^{-1} ) per metre. What is the torque experienced by a system having a total dipole moment equal to ( 10^{-7} mathrm{C}-mathrm{m} ) in the negative z-direction? A. 2 N-m B. 3 N-m c. ( 4 mathrm{N}-mathrm{m} ) D. zero |
12 |

628 | Assertion Work done by the electrostatic field on a charge moving around a closed circular or elliptical path will be zero. Reason Electrostatic field is a conservative field. A. Both Assertion and Reason are correct and Reason is the correct explanation for Assertion B. Both Assertion and Reason are correct but Reason is not the correct explanation for Assertion c. Assertion is correct but Reason is incorrect D. Assertion is incorrect but Reason is correct |
12 |

629 | Electric field lines of force A. exist everywhere B. exist only in the immediate vicinity of electric charges C. exist only when both positive and negative charges are near one another D. are imaginary |
12 |

630 | When electrophorus is charged, the electricity is obtained from : A. Cat’s skin B. Metallic plate c. sole D. Ebonite plate |
12 |

631 | Two identical spheres having charges ( 8 mu C ) and ( -4 mu C ) are kept at a certain distance apart. Now they are brought into contact, after that again they are kept at the same distance. Compare the forces in the two cases A . 4: 1 B. 12: 1 c. 8: 1 D. 16: 1 |
12 |

632 | An electric dipole of dipole moment ( vec{p} ) is placed in a uniform electric field ( vec{E} ). The maximum torque experienced by the dipole is A ( . p E ) в. ( p / E ) c. ( E / p ) D . ( vec{p} . vec{E} ) |
12 |

633 | Bulbs in street lightning are all connected in A. parallel B. series c. series-parallel D. end-to-end |
12 |

634 | On which factors from below does Coulomb’s law(i.e. law of electrostatic attraction and repulsion) depends? A. Magnitude of charges B. Distance between charges c. Both magnitude and distance between charges D. None of the above |
12 |

635 | Consider a uniform electric field ( boldsymbol{E}= ) ( 3 times 10^{3} hat{i} N C^{-1} ) (a) What is the flux of this field through a square of ( 10 mathrm{cm} ) on a side whose plane is parallel to the yz plane? (b) What is the flux through the same square if the normal to its plane makes a ( 60^{circ} ) angle with the ( x ) -axis? |
12 |

636 | Gauss’s law is true only if force due to a charge varies as A ( cdot r^{-1} ) B . ( r^{-2} ) ( c cdot r^{-3} ) D. ( r^{-4} ) |
12 |

637 | Three charges ( +4 q, Q ) and ( +q ) are placed in a straight line with ( Q ) midway in between the other two charges. If net force on ( +boldsymbol{q} ) is zero, the charge ( boldsymbol{Q} ) must be: A. ( -q ) в. ( -2 q ) c. ( frac{-q}{2} ) D. |
12 |

638 | The electric potential at a point on the equatorial line of an electric dipole is A. directly proportional to distance B. inversely proportional to distance c. inversely proportional to square of the distance D. none of the above |
12 |

639 | A charge ( Q ) is distributed over two concentric hollow spheres of radii ( r ) and ( R(>r) ) such that the surface densities are equal. Find the potential at the common centre |
12 |

640 | A glass rod when rubbed with silk cloth, acquires a charge of ( 1.6 times 10^{-11} C ), then the charge on silk cloth will be: A. ( -3.2 times 10^{-11} C ) B . ( -2.4 times 10^{-13} C ) c. ( -1.6 times 10^{-13} C ) D. ( -1.6 times 10^{-11} C ) |
12 |

641 | In the figure shown here, ( A ) is a conducting sphere and ( mathrm{B} ) is a closed spherical surface. If a-q change is placed at ( C ) near ( A ), then the electric flux through the closed surface is – A . zero B. positive c. negative D. none of the above can be predicted |
12 |

642 | Two particles ( X ) and ( Y ), of equal mass and with unequal positive charges, are free to move and are initially far away from each other. With ( Y ) at rest, ( X ) begins to move towards it with initial velocity ( u ). After a long time, finally A. ( X ) will stop, ( Y ) will move with velocity ( u ) B. ( X ) and ( Y ) will both move with velocities ( u / 2 ) each c. ( X ) will stop, ( Y ) will move with velocity ( <u ) D. both will move with velocities ( <u / 2 ) |
12 |

643 | Two spheres of radius ( 5 mathrm{cm} ) and ( 10 mathrm{cm} ) both charged to ( 120 mu C ), are joined by a metal wire and then metal wire is removed. What is the charge on each after removal of the wire? ( mathbf{A} cdot 120 mu C, 120 mu C ) в. ( 80 mu C, 160 mu C ) c. ( 100 mu C, 140 mu C ) D. None of these |
12 |

644 | A short dipole is placed along the ( x ) -mds at ( x=x text { (Fig. } 3.120) ) a. Find the force acting on the dipole due to a point charge q placed at the origin. b. Find the force on the dipole if the dipole is rotated by ( 180^{circ} ) about the z-axis. c. Find the force on dipole if the dipole is rotated by ( 90^{circ} ) anticlockwise about z-axis, i.e., it becomes parallel to the ( y ) -axis. |
12 |

645 | Which among the following is the best conductor of electricity? A. Oxygen B. Aluminium c. carbon D. woodd |
12 |

646 | The process suitable for charging a glass rod is : A. conduction B. induction c. rubbing against a suitable substance D. all of the above |
12 |

647 | Two copper spheres, ( A ) and ( B ), are identical in all respect but A carries a charge of ( -3 mu C ) whereas ( B ) Is charged to ( +1 mu C ). The two spheres are brought together until they touch and then separated by some distance. Which of the following statements is true concerning the electrostatic force ( boldsymbol{F} ) between the spheres? A. ( F=0 ) as one of the spheres is uncharged B. ( F=0 ) as both the spheres are uncharged c. ( F ) is attractive D. F is repulsive |
12 |

648 | Two charges equal in magnitude and opposite in polarity are placed at a certain distance apart and effective force between them is ( F ). If ( 75 % % ) charge of one is transferred to another, then the effective force between the charges becomes: A ( cdot frac{F}{16} ) в. ( frac{9 F}{16} ) ( c . F ) D. ( frac{15}{16} ) |
12 |

649 | The electric field components due to a charge inside the cube of side ( 0.1 mathrm{m} ) are shown in figure. where, ( boldsymbol{E}_{boldsymbol{x}}=boldsymbol{alpha}, ) where ( boldsymbol{alpha}=500 mathrm{N} / mathrm{C}-mathrm{m} ) ( boldsymbol{E}_{boldsymbol{y}}=mathbf{0}, boldsymbol{E}_{boldsymbol{z}}=mathbf{0} ) Calculate (a) the flux through the cube and (b) the charge inside the cube. |
12 |

650 | Three concentric metallic shells ( A, B ) and ( C ) of radii ( a, b ) and ( c(a<b<c) ) have surface charge densities, ( sigma,-sigma ) and ( sigma ) respectively. Find the potentials of three shells ( A, B ) and ( C ). |
12 |

651 | Eight point charges (can be assumed as small spheres uniformly charged and their centres at the corner of the cube) having values q each are fixed at vertices of a cube .The electric flux through square surface ABCD of the cube is A ( cdot frac{q}{24 epsilon_{n}} ) B. ( frac{q}{12 epsilon_{0}} ) c. ( frac{q}{6 epsilon_{0}} ) D. ( frac{q}{8 epsilon_{0}} ) |
12 |

652 | 4 | 12 |

653 | For the circuit shown in figure, the direction and magnitude of the force on PQR is: A . zero B. ILB out of the page c. ILB/2 into the page D. ILB into the page |
12 |

654 | Three charged particles are in equilibrium under their electrostatic forces only, then: This question has multiple correct options A. The particle are collinear B. All the charges cannot have the same magnitude c. All the charges cannot have the same sign D. The equilibrium is unstable |
12 |

655 | Two charges are placed a certain distance apart. A metallic sheet is placed between them. What will happen to the force between the charges? A. Increase B. Decrease c. No change D. either ‘a’ or ‘b |
12 |

656 | If ( Q_{1}=5 mu C, Q_{2}=3 mu C ) and ( Q_{3}= ) ( -2 mu C, ) then the net charge in the system is : A. ( -6 mu C ) в. ( 6 mu C ) ( c cdot 8 mu C ) D. ( -2 mu C ) |
12 |

657 | An electric dipole placed in a nonuniform electric field may experiences: A. a force but no torque B. a torque but no force c. a force as well as a torque D. neither a force nor a torque |
12 |

658 | An electric dipole is held in a uniform electric field (i) Using diagram show that it does not undergo any translatory motion, (ii) derive an expression for torque acting on it. |
12 |

659 | At a certain location, the strength of the electric field is ( 30.0 N / C . ) A charge of ( 3.00 C ) is placed at this location. How much force does this charge experience due to the electric field? A. ( 90.0 N ) n B . ( 10.0 N ) c. ( 0.100 N ) D. ( 270 N / C ) E . ( 3.33 N / C ) |
12 |

660 | Among identical spheres ( A ) and ( B ) having charges as ( -5 C ) and -16 C A. – -5C is at higher potential B. -16C is at higher potential c. Both are at equal potential D. It cannot be said |
12 |

661 | An electric dipole is placed in an electric field generated by a point charge. A. The net electric force on the dipole must be zero B. The net electric force on the dipole may be zero c. The torque on the dipole due to the field must be zero. D. The torque on the dipole due to field may be zero |
12 |

662 | radii ( 2 R ) and ( 4 R ) respectively are kept at distances ( x ) and ( 2 x ) from the point charge ( q . ) A surface cutout of a non conducting shell ( C ) is kept such that its centre coincides with the point charge. Each plate and the spherical surface carries a surface charge density ( sigma . ) If ( phi_{1} ) is flux through surface of ( (B) ) due to electric field of ( (A) ) and ( phi_{2} ) be the flux through ( (A) ) due to electric field of ( (B) ) then: ( mathbf{A} cdot phi_{1}=phi_{2} ) ( mathbf{B} cdot phi_{1}>phi_{2} ) ( mathbf{c} cdot phi_{1}<phi_{2} ) D. It depend ( R ) |
12 |

663 | The electric field in a region is given by ( overrightarrow{boldsymbol{E}}=frac{mathbf{3}}{mathbf{5}} boldsymbol{E}_{boldsymbol{o}} hat{boldsymbol{i}}+frac{boldsymbol{4}}{mathbf{5}} boldsymbol{E}_{boldsymbol{o}} widehat{boldsymbol{j}} ) with ( boldsymbol{E}_{boldsymbol{o}}=boldsymbol{2} boldsymbol{0} times mathbf{1 0}^{boldsymbol{3}} ) N/C. Find the flux of this field (in ( left.N m^{2} C^{-1}right) ) through a rectangular surface of area ( 0.2 mathrm{m}^{2} ) parallel to the ( mathrm{Y}-mathrm{Z} ) plane. |
12 |

664 | When a glass rod is rubbed with silk, it is said to be positively charged. Which of the following statement is true? A. Electrons move from silk to glass B. Electrons move from glass to silk c. Protons move from silk to glass D. Protons move from glass to silk |
12 |

665 | A charge ( +10^{-9} C ) is located at the origin in free space and another charge ( Q ) at ( (2,0,0) . ) If the ( X ) -component of the electric field at (3,1,1) is zero. The value of ( Q ) is A ( cdot 2.4 times 10^{-10} mathrm{C} ) В. ( -6.2 times 10^{-20} C ) c. ( -4.3 times 10^{-10} C ) D. ( -1.2 times 10^{-20} C ) |
12 |

666 | If the number of electric lines of force emerging out of a closed surface is ( 1000, ) then the charge enclosed by the surface is A ( cdot 8.854 times 10^{-9} C ) В. ( 8.854 times 10^{-4} C ) c. ( 8.854 times 10^{-1} C ) D. ( 8.854 C ) |
12 |

667 | A cylinder of radius ( R ) and length ( l ) is placed in a uniform electric field ( boldsymbol{E} ) parallel to the axis of the cylinder. The total flux over the curved surface of the cylinder is : A. zero B ( cdot pi R^{2} E ) ( mathbf{c} cdot 2 pi R^{2} E ) D. ( E / pi R^{2} ) |
12 |

668 | Two charged conducting spheres of radii a and b are connected to each other by a wire. What is the ratio of electric fields at the surfaces of the two spheres? Use the result obtained to explain why charge density on the sharp and pointed ends of a conductor is higher than on its flatter portions. |
12 |

669 | Which of these is a good electrical conductor? A. water B. Sweat c. The human body D. All of the above |
12 |

670 | A charged spherical conductor has a surface charge density of ( 0.07 C / m^{2} ) When its charge is increased by ( 0.44 C ) the charge density changes by 0.14 ( C / m^{2} . ) The radius of the sphere is : A . ( 5 mathrm{cm} ) в. ( 10 m ) c. ( 0.5 m ) D. ( 5 m ) |
12 |

671 | The potential at a point ( (x, 0,0) ) is given by ( V=left(frac{1000}{x}+frac{1500}{x^{2}}+frac{500}{x^{3}}right) . ) The intensity of the electric field at ( x=1 ) will be A. ( 550 V / m ) B. ( 55 V / m ) ( mathbf{c} .55000 V / m ) D. ( 5500 V / m ) |
12 |

672 | Electroscope is an instrument used to find the quantity of charge on different bodies. A. True B. False |
12 |

673 | Electric field due to an infinite sheet of charge having surface density ( sigma ) is ( E ) Electric field due to an infinite conducting sheet of same surface density of charge is A. ( E / 2 ) в. ( E ) ( c .2 E ) D. ( 4 E ) |
12 |

674 | In which of the following states is the potential energy of an electric dipole maximum? ( A ) B. ( c ) D. |
12 |

675 | If the electric field in some region of space is zero, A. it implies that there is no electric charge in that region. B. it implies that there is electric charge in that region. C. it does not imply anything concrete about the charges in the region. D. it means there is discharging in the region |
12 |

676 | An electric field is uniform, and in the positive ( x ) direction for positive ( x, ) and uniform with the same magnitude but in the negative ( x ) direction for negative ( x . ) It is given that ( boldsymbol{E}=mathbf{2 0 0} hat{boldsymbol{i}} boldsymbol{N} / boldsymbol{C} ) for ( boldsymbol{x}>mathbf{0} ) and ( boldsymbol{E}=-mathbf{2 0 0} hat{boldsymbol{i}} boldsymbol{N} / boldsymbol{C} ) for ( boldsymbol{x}<mathbf{0 . A} ) right circular cylinder of length ( 20 mathrm{cm} ) and radius ( 5 mathrm{cm} ) has its centre at the origin and its axis along the ( x ) -xis so that one face is at ( x=+10 mathrm{cm} ) and the other is at ( x=-10 mathrm{cm} ) (a) What is the net outward flux through each flat face? (b) What is the flux through the side of the cylinder? (c) What is the net outward flux through the side of the cylinder? |
12 |

677 | A particle of mas ( m ) carrying charge ( q ) is released from restm in a uniform electric field of intensity ( boldsymbol{E} ). The kinetic energy acquired by the particle after moving a distance of ( x ) is (neglect gravitational force): A ( . q E x ) В ( cdot q E x^{2} ) ( mathbf{c} cdot q E^{2} x ) D. ( q^{2} E x ) |
12 |

678 | You are provided with a negatively charged gold leaf electroscope. State and explain what happens when an uncharged metal rod is brought near the disc of electroscope. A. Divergence increases B. Divergence decreases c. Divergence remains same D. can’t say |
12 |

679 | Figure shows three point charges ( +2 q,-q a n d+3 q . ) Two charges ( +2 q ) and ( q ) are enclosed within a surface ( boldsymbol{S} ) What is the electric flux due to this configuration through the surface ( S ? ) |
12 |

680 | A glass rod when rubbed with silk cloth acquires a charge ( 1.6 times 10^{-13} C . ) What is the charge on the silk cloth? A ( .-1.6 times 10^{-19} C ) В. ( 1.6 times 10^{-13} C ) c. ( -1.6 times 10^{-13} C ) D. ( 1.6 times 10^{-19} C ) |
12 |

681 | Define relative premittivity. Write its unit. |
12 |

682 | In a certain region of space,electric field is along the z-direction throughout The magnitude of electric field is however not constant, but increases uniformly along the positive z-direction at the rate of ( 10^{5} N quad C^{-1} m^{-1} . ) Torque experienced by the system is: ( mathbf{A} cdot 10^{2} N ) В. ( 10^{-2} N ) c. zero D. ( 10^{3} N ) |
12 |

683 | A sphere of radius ( r ) is charged to a potential ( V . ) The outward pull per unit area of its surface is given by: A ( cdot frac{4 pi epsilon_{0} V^{2}}{r^{2}} ) в. ( frac{epsilon_{0} V^{2}}{r^{2}} ) c. ( frac{2 pi epsilon_{0} V^{2}}{r^{2}} ) D. ( frac{epsilon_{0} V^{2}}{4 r^{2}} ) |
12 |

684 | A very long, straight, then wires carries ( -3.60 n C m^{-1} ) of fixed negative charge. The wire is to be surrounded by a uniform cylinder of positive charge, radius ( 1.50 mathrm{cm} ), coaxial with the wire. The volume charge density ( rho ) of the cylinder is to be selected so that the net electric field outside the cylinder is zero. Calculate the required positive charge density ( rholeft(operatorname{in} mu C m^{-3}right) ) ( A ) в. 7 ( c .5 ) ( D ) |
12 |

685 | A right circular cone has a semi-vertical angle ( alpha . ) Calculate the solid angle at the apex P of the cone. A ( cdot d Omega=2 pi(1-cos alpha) ) в. ( d Omega=2 pi(1-sin alpha) ) c. ( d Omega=2 pi(cos alpha) ) D. ( d Omega=2 pi(sin alpha) ) |
12 |

686 | Two isolated metallic solid sphere of radius ( R ) and ( 2 R ) are charged such that both of these have same charge density a. the spheres are locted far away from each other and are connected by a thin conducting wire . the new charge density on the bigger sphere is A ( cdot frac{5 sigma}{6} ) в. ( frac{56 sigma}{5} ) c. ( frac{3 sigma}{5} ) D. ( frac{52 sigma}{6} ) |
12 |

687 | A solid sphere of radius ( R ) has a charge ( Q ) distributed in its volume with a charge density ( rho=kappa r^{a}, ) where ( kappa ) and ( a ) are constants and ( r ) is the distance from its centre. If the electric field at ( r=frac{R}{8} ) is ( frac{1}{8} ) times that at ( r=R, ) find the value of ( a ) A . 2.0 B. 3.2 c. 2.5 D. 0.2 |
12 |

688 | Charges ( Q, 2 Q ) and ( 4 Q ) are uniformly distributed in three dielectric solid spheres 1,2 and 3 of radii ( mathrm{R} / 2, mathrm{R} ) and ( 2 mathrm{R} ) respectively. If magnitudes of the electric fields at point ( P ) at a distance ( R ) from the centre of spheres 1,2 and 3 are ( E_{1}, E_{2}, ) and ( E_{3} ) respectively, then: A. ( E_{1}>E_{2}>E_{3} ) в. ( E_{3}>E_{1}>E_{2} ) c. ( E_{2}>E_{1}>E_{3} ) D. ( E_{3}>E_{2}>E_{1} ) |
12 |

689 | A hollow conducting sphere is placed in an electric field produced by a point charge placed at point ( A, B ) and ( C ) respectively, then: A. ( V_{C}>V_{B} ) B . ( V_{A}>V_{B} ) с. ( V_{B}>V_{c} ) ( mathbf{D} cdot V_{C}=V_{B} ) |
12 |

690 | If there is only one type of charge in the universe, then what is the flux to the entire universe. ( (vec{E} rightarrow text { Electric field, } overrightarrow{d s} rightarrow ) Area vector) ( mathbf{A} cdot oint vec{E} cdot overrightarrow{d s} neq 0 ) on any surface B. ( oint vec{E} cdot overrightarrow{d s} ) could not be defined ( mathbf{c} cdot oint vec{E} cdot overrightarrow{d s}=infty ) if charge is inside D ( cdot oint vec{E} cdot overrightarrow{d s}=0 ) if charge is outside, ( =frac{q}{epsilon_{0}} ) if charge is inside |
12 |

691 | Q Type your question positioned al poinis 1 and ( 4, ) ine ( 11 € ) id intensity to the right of the charge ( Q_{2} ) on the line that passes through the two charges varies according to a law that is represented schematically in the figure. The field intensity is assumed to be positive if its direction coincides with |
12 |

692 | ( n ) small drops of same size are charged to ( V ) volts each. If they coalesce to form a signal large drop, then its potential will be : A. ( V / n ) в. ( V n ) ( mathbf{c} cdot V n^{1 / 3} ) ( mathbf{D} cdot V n^{2 / 3} ) |
12 |

693 | Two connected charges of ( +q ) and ( -q ) respectively are at a fixed distance ( boldsymbol{A B} ) apart in a non uniform electric field whose lines of force are shown in the figure. The resultant effect on the two charges is A. a torque in the plane of the paper and no resultant force B. a resultant force in the plane of the paper and no torque c. a torque normal to the plane of the paper and no resultant force D. a torque normal to the plane of the paper and a resultant force in the plane of the paper |
12 |

694 | Assertion A positively charged particle always moves along the electric lines of forces. Reason Force on a charged particle is tangential to the electric lines of force. A. Both Assertion and Reason are correct and Reason is the correct explanation for Assertion B. Both Assertion and Reason are correct but Reason is not the correct explanation for Assertion c. Assertion is correct but Reason is incorrect D. Assertion is incorrect but Reason is correct |
12 |

695 | Value of electric potential at the center of uniformly charged non conducting sphere is 30 volt then what will be value of potential at surface. | 12 |

696 | Consider a circle of radius ( R ). A point charge lies at a distance ( a ) from its center and on its axis such that ( boldsymbol{R}= ) ( a sqrt{3} . ) If electric flux passing through the circle is ( phi, ) find the magnitude of the point charge. |
12 |

697 | How much positive and negative charge is there in a cup of water? Take mass of 1 cup of water as 250 g. Mass of ( 6.02 times 10^{23} ) molecules of water is 18 g. |
12 |

698 | A gold leaf electroscope is used A. Detect the presence of charge on a body B. Know the nature of charge on a charged body C. Find the amount of charge present on a charged body D. Both 1 and 2 |
12 |

699 | Forces between electric charges in relative motion are called: A. Electromagnetic force B. Electrostatic force c. Both a and D. None of these |
12 |

700 | The Sl unit of electric flux is A. Voltmetre B. Joule/Metre c. Newton D. None |
12 |

701 | A hollow cylinder has a charge ( q ) coulomb within it. If ( f ) the electric flux in units of volmeter associated with the curved surface ( mathrm{B} ), the fl乂 linked with the plane surface A in units of V-m will be: A ( cdot frac{q}{2 varepsilon_{0}} ) в. ( frac{Phi}{3} ) c. ( frac{q}{varepsilon_{0}} ) D. ( frac{4 q}{varepsilon_{0}} ) |
12 |

702 | What does coulomb’s law of attraction and repulsion states? ( mathbf{A} cdot F ) is directly proportional to ( q_{1} q_{2} ) and inversely proportional to ( left(r_{12}right)^{2} ) B. F is directly proportional to ( q_{1} q_{2} ) and inversely proportional to ( left(r_{12}right) ) C. ( F ) is indirectly proportional to ( q_{1} q_{2} ) and directly proportional to ( left(r_{12}right)^{2} ) D. None |
12 |

703 | Three concentric conducting spherical shells of radii ( boldsymbol{R}, 2 boldsymbol{R} ) and ( boldsymbol{3} boldsymbol{R} ) carry charges ( Q,-2 Q ) and ( 3 Q, ) respectively. Compute the potential at ( r=frac{5}{2} R: ) ( A ) В. ( frac{-3 Q}{25 pi varepsilon_{0} R} ) ( c ) D. |
12 |

704 | The electric field in a region of space is given by ( overrightarrow{boldsymbol{E}}=boldsymbol{E}_{0} hat{boldsymbol{i}}+boldsymbol{2} boldsymbol{E}_{boldsymbol{o}} hat{boldsymbol{j}} ) where ( boldsymbol{E}_{boldsymbol{o}}= ) ( mathbf{1 0 0} N / C . ) The flux of this field through a circular surface of radius ( 0.02 mathrm{m} ) parallel to the ( Y ) -Z plane is nearly: A ( cdot 0.125 mathrm{Nm}^{2} / mathrm{C} ) B . ( 0.02 mathrm{Nm}^{2} / mathrm{C} ) c. ( 0.005 mathrm{Nm}^{2} / mathrm{C} ) D. ( 3.14 mathrm{Nm}^{2} / mathrm{C} ) |
12 |

705 | Ten positively charged particles are kept fixed on the ( x- ) axis at points ( x= ) ( 10 mathrm{cm}, 20 mathrm{cm}, 30 mathrm{cm}, ldots ., 100 mathrm{cm} . ) The first particle has a charge ( 1.0 times 10^{-8} C ) the second ( 8 times 10^{-8} C, ) the third ( 27 times ) ( 10^{-8} C ) and so on. The tenth particle has a charge ( 1000 times 10^{-8} C . ) Find the magnitude of the electric force acting on a ( 1 C ) charge placed at the origin. ( mathbf{A} cdot 5.94 times 10^{5} N ) B . ( 5.49 times 10^{5} N ) c. ( 9.45 times 10^{5} N ) D. ( 4.95 times 10^{5} N ) |
12 |

706 | An electric dipole is placed at the centre of a sphere. Mark the correct option: This question has multiple correct options A. the flux of the electric field through the sphere is zero B. the electric field is zero at every point of the sphere C. the electric field is not zero anywhere on the sphere D. the electric field is zero on a circle on the sphere |
12 |

707 | If coulomb’s law involved ( 1 / r^{3} ) instead of ( left(1 / r^{2}right), ) would Gauss’s law still be true? |
12 |

708 | Objects with the same type of charges attract each other. A . True B. False |
12 |

709 | An insulating sphere with radius a has a uniform charge density ( rho . ) The sphere is not centered at the origin but at ( r=b ) Find the electric field at any point inside sphere is ( boldsymbol{E}=frac{boldsymbol{rho}(boldsymbol{x}-boldsymbol{b})}{boldsymbol{n} varepsilon_{0}} . ) what is the value of ( n ) |
12 |

710 | There are two concentric spherical shells of radii r and 2r. Initially a charge ( mathrm{Q} ) is given to the inner shell.Now, switch ( S_{1} ) is closed and opened then ( S_{2} ) is closed and opened and the process is repeated ( n ) times for both the keys alternatively. Find the final potential difference between the shells |
12 |

711 | An electric field of ( 1000 mathrm{V} / mathrm{m} ) is applied to an electric dipole at angle of ( 45^{circ} . ) The value of electric dipole moment is ( 10^{-29} ) C.m. What is the potential energy of the electric dipole? B. ( -7 times 10^{-27} ) j ( c cdot-10 times 10^{-29} ) D. ( -20 times 10^{-18} mathrm{J} ) |
12 |

712 | If the flux of the electric field through a closed surface is zero: A. the electric field must be zero everywhere on the surface B. the electric field must not be zero everywhere on the surface C. the charge inside the surface must be zero D. the charge in the vicinity of the surface must be zero |
12 |

713 | The work done to rotate the electric dipole from the equilibrium position by ( 180^{0} ) is : A. ( 3 times 10^{-23} J ) В. ( 6 times 10^{-23} J ) c. ( 12 times 10^{-23} J ) D. Zero |
12 |

714 | Three identical positive charges each of value ( Q ) are arranged at the vertices of an equilateral triangle of side length a. The intensity of the electric field at the vertex of a regular tetrahedron of which the triangle is the base is: A ( cdot frac{sqrt{6} k Q}{a^{2}} ) B. ( frac{sqrt{2} text { КQ }}{frac{a^{2}}{2}} ) c. ( frac{sqrt{3} kappa Q}{a^{2}} ) D. None |
12 |

715 | The normal electric flux per unit area is called This question has multiple correct options A. Electric field intensity B. Electric force c. Electric flux density D. Electric potential |
12 |

716 | Until when does the charged particle transmits charge to other? A. Until the overall repulsive forces between electrons is minimised. B. Until the overall repulsive forces between electrons is maxmised. C. Until the overall repulsive forces between electrons is become neutral D. None |
12 |

717 | Two similar balls, each of mass ( mathrm{m} ) and charge ( q, ) are hung from a common point by two silk threads, each of length I. Prove that separation between the balls is ( boldsymbol{x}=left[frac{boldsymbol{q}^{2} boldsymbol{l}}{2 boldsymbol{pi} varepsilon_{0} boldsymbol{m} boldsymbol{g}}right]^{1 / 3}, ) if ( boldsymbol{theta} ) is small. Find the rate da/dt with which the charge should leak off each sphere if the velocity of approach varies as ( boldsymbol{v}= ) ( a / sqrt{x}, ) where a is a constant |
12 |

718 | The flux linked with a circuit is given by ( phi=(t-2)^{2} . ) The graph between induced emf (y-axis) and time axis ( (x- ) axis) is A. Straight line through origin B. Straight line with negative intercept c. straight line with positive intercept D. Parabola |
12 |

719 | An electron, proton, deuteron and ( alpha ) particle enter in a uniform electric field with the same velocity as shown. The greatest deviation is shown by A. electron B. proton c. deuteron D. ( alpha ) – particle |
12 |

720 | Poor conductors of electricity consist of A . silver B. aluminum c. distilled water D. copper |
12 |

721 | The conservation of electric charge implies that This question has multiple correct options A. charge cannot be created B. charge cannot be destroyed C. the number of charged particles in the universe is constant D. simultaneous creation of equal and opposite charges is permissible |
12 |

722 | Find the direction of electric field at point ( boldsymbol{P} ) for the charge distribution as shown in the figure. A. Along positive ( y ) -axis B. Along negative ( y ) -axis c. Along positive ( x ) -axis D. Along negative ( x ) -axis |
12 |

723 | What will be the effect on the divergence of the leaves of a uncharged gold leaf electroscope on bringing a negatively charged rod near electroscope? A. Leaves diverge B. Leaves converge c. Leaves remains at same position D. Can not be determined |
12 |

724 | A light beam travelling in the ( x ) direction is described by the electric field ( boldsymbol{E}_{boldsymbol{y}}=left(mathbf{3 0 0} boldsymbol{V} boldsymbol{m}^{-1}right) sin quad boldsymbol{omega}(boldsymbol{t}-boldsymbol{x} / boldsymbol{c}) ) An electron is constrained to move along the y-direction with a speed of ( 2.0 times 10^{7} m^{-1} ) Find the maximum electric force and the maximum magnetic force on the electron A ( cdot 4.8 times 10^{-17} mathrm{N}, ) zero В. ( 4.2 times 10^{-18} N, 1.8 times 10^{-8} N ) c. ( 4.8 times 10^{-17} N, 3.2 times 10^{-18} N ) D. zero, zero |
12 |

725 | A line of charge extends along a X-axis whose linear charge density varies directly as x. Imagine a spherical volume with its centre located on X-axis and is moving gradually along it. Which of the graphs shown in figure correspond to the flux with the ( x ) coordinate of the centre of the volume ( A ) B. ( c ) ( D . d ) |
12 |

726 | When electrons in a material are free to move, the material is: A. an insulator B. a conductor c. a semiconductor D. none of these |
12 |

727 | Which of the following materials is an electrical insulator? A. Aluminium B. Gold c. Rubber D. all of these |
12 |

728 | Electric field intensity at a point due to a charge ( Q ) is ( 24 mathrm{N} / mathrm{C} ) and electric potential at ( A^{prime} ) due to charge ( Q ) is ( =12 mathrm{j} / mathrm{C} ) The distance between the charges and magnitude of ( Q ) are A ( cdot 0.4 m, 0.667 times 10^{-9} mathrm{C} ) B . ( 0.4 m, 6.67 times 10^{-4} mathrm{C} ) c. ( 0.5 m, 2.67 times 10^{-9} mathrm{C} ) D. ( 0.5 m, 7.66 times 10^{-9} mathrm{C} ) |
12 |

729 | Assertion Gauss’s law show diversion when inverse square law is not obeyed. Reason Gauss’s law is a consequence of |
12 |

730 | A thin spherical conducting shell of radius ( R ) has a charge ( q ). Another charge ( Q ) is placed at the centre of the shell. The electrostatic potential at a point ( mathrm{P} ) at a distance ( boldsymbol{R} / mathbf{2} ) from the centre of the shell is : ( ^{A} cdot frac{2 Q}{4 pi varepsilon_{Omega} R} ) в. ( frac{2 Q}{4 pi varepsilon_{0} R}-frac{2 q}{4 pi varepsilon_{0} R} ) c. ( frac{2 Q}{4 pi varepsilon_{0} R}+frac{q}{4 pi varepsilon_{0} R} ) D. ( frac{(q+Q) 2}{4 pi varepsilon R R} ) |
12 |

731 | The electric field in the region with radius ( r, ) where ( c>r>b, ) is |
12 |

732 | Two point charges of magnitude ( +10^{8} ) coulomb each are placed 0.5 metre in air. At the mid point of line joining then A. The field is zero, the potential is zero B. The field is zero, the potential is not zero c. The field is zero the potential is -720 D. The field is zero the potential is + 720 |
12 |

733 | The surface charge density on a copper sphere is ( sigma . ) So the intensity of electric field on its surface will be: A. ( sigma ) B. ( frac{sigma}{2} ) c. ( frac{sigma}{2 varepsilon o} ) D. ( frac{sigma}{varepsilon o} ) |
12 |

734 | Two point charges ( +q ) and ( -2 q ) are kept ( d ) distance apart Find the location of the points on the line joining the two charges at which potential due to this system of charges is zero. | 12 |

735 | Four point charges are fixed in position at the corners of a square, as shown in above figure Find out the direction of the total electrostatic force on the charge in the lower right-hand corner of the square? A. B. 4 ( c ) ( D ) E. The electric force on this charge is |
12 |

736 | Two particle of equal mass ( m ) and charge ( q ) are placed at a distance of 16cm. They do not experience any force. The value of ( frac{boldsymbol{q}}{boldsymbol{m}} ) is : A. ( sqrt{frac{pi varepsilon_{0}}{G}} ) в. ( L ) c. ( sqrt{frac{G}{pi varepsilon_{0}}} ) D. ( sqrt{4 pi varepsilon_{0} G} ) |
12 |

737 | Find the angular speed of the rod as the function of angle ( theta ) of rotation ( omega=f(theta) ) if the rod is allowed to rotate freely |
12 |

738 | An electron moves a distance of ( 6 mathrm{cm} ) when accelerated from rest by an electric field of strength ( 2 times 10^{4} N C^{-1} ) Calculate the time of travel. (mass of electron ( left.=9.1 times 10^{-31} k gright) ) |
12 |

739 | Define one coulomb charge. | 12 |

740 | The breakdown field for air is about ( 2 x ) ( mathbf{1 0}^{6} ) volt/m. Therefore, the maximum charge that can be placed on a sphere of diameter ( 10 mathrm{cm} ) is A ( .2 .0 times 10^{-4} mathrm{c} ) В. ( 5.6 times 10^{-7} mathrm{c} ) c. ( 5.6 times 10^{-2} mathrm{c} ) D . ( 2.0 times 10^{2} mathrm{c} ) |
12 |

741 | What causes electrification of two bodies when they are rubbed together? A. Transfer of atoms from one body to the other body. B. Transfer of electricity from one body to the other body. C. Transfer of electrons from one body to the other body. D. Transfer of heat from one body to the other body. |
12 |

742 | A closed surface in the shape of a cube is placed in a uniform electric field ( boldsymbol{E} ) along one of the sides of the cube as shown here. The length of the side is ( l ) The total electric flux through two faces 1 and 2 is: A . zero B. ( -E l^{2} ) ( c cdot 2 E l^{2} ) D. ( frac{E l^{2}}{2} ) |
12 |

743 | Two small beads having positive charges ( 3 q ) and ( q ) are fixed at the opposite ends of a horizontal, insulating rod, extending from the origin to the point ( boldsymbol{x}=boldsymbol{d} . ) As shown in figure, a third small charged bead is free to slide on the rod. At what position is the third bead in equilibrium? Can it be in stable equilibrium? A ( cdot frac{sqrt{3} d}{(1+sqrt{3})} ) from ( +3 q ) charge, yes B. ( frac{sqrt{5} d}{(1+sqrt{3})} ) from ( +3 q ) charge, yes C ( frac{sqrt{3} d}{(1+sqrt{2})} ) from ( +3 q ) charge, yes D. ( frac{sqrt{2} d}{(1+sqrt{3})} ) from ( +3 q ) charge, yes |
12 |

744 | Two point charges placed at a certain distance ( r ) in air exert a force ( F ) on each other. The distance ( r ) at which these charges will exert the same force in medium if dielectric constant k is given by ( A ) в. ( frac{r}{k} ) c. ( frac{r}{sqrt{k}} ) D. none of these |
12 |

745 | If the electric field is given by ( (5 i+ ) ( 4 j+9 k), ) the electric flux through a surface of area 20 unit lying in the ( Y-Z ) plane will be : A. 100 unit B. 80 unitt c. 180 unit D. 20 unit |
12 |

746 | A charge of ( +2 mu C ) is placed at ( x=0 ) and a charge of ( -32 mu C ) at ( x=60 mathrm{cm} . ) Athird charge – ( Q ) be placed on the ( x ) -axis such that it experiences no force. The distance of the point from ( +2 mu C ) is (in ( (m) ) ( A cdot 30 ) B. 20 c. 15 D. 10 |
12 |

747 | Electric lines of force about a negative point charge are: A. Circular anti-clockwise B. Circular clockwise c. Radially inwards D. Radially outwards |
12 |

748 | Torque acting on an electric dipole in a uniform electric field is maximum if the angle between ( vec{P} ; ) and ( vec{E} ) is: A ( .180^{circ} ) B . ( 0^{circ} ) ( c cdot 90^{circ} ) D. ( 45^{circ} ) |
12 |

749 | Define the following term. Volume charge density. | 12 |

750 | Positive point charges are placed at the vertices of a star shape as shown in the figure. Direction of the electrostatic force on a negative point charge at the centre ( boldsymbol{O} ) of the star is: A. Neither along horizontal or vertical direction, B. Vertically up C. Towards left D. Vertically down |
12 |

751 | An electric dipole moment ( vec{P}=(2.0 hat{i}+3.0 hat{j}) mu C . . m ) is placed in a uniform electric field ( vec{E}=(3.0 hat{mathrm{i}}+2.0 widehat{k}) times 10^{5} ) A ( cdot ) The torque that ( overrightarrow{mathrm{E}} ) exert on ( overrightarrow{mathrm{P}} ) is ( (0.6 hat{mathrm{f}}+0.4 hat{mathrm{j}}-0.9 widehat{mathrm{k}}) mathrm{Nm} ) B. The potential energy of the dipole is -0.6 c. The potential energy of the dipole is 0.6 . D. None of these |
12 |

752 | Electron accelerated by potential ( V ) are diffracted from a crystal. If ( boldsymbol{d}=mathbf{1} boldsymbol{A} ) and ( boldsymbol{i}=mathbf{3 0}^{circ} . boldsymbol{V} ) should be about ( boldsymbol{h}=mathbf{6 . 6} times ) ( mathbf{1 0}^{-mathbf{2 4}} mathbf{J s m}_{e}=mathbf{9 . 1} times mathbf{1 0}^{-mathbf{3 3} mathbf{k g} . boldsymbol{e}}= ) ( mathbf{1} . mathbf{6} times mathbf{1 0}^{-mathbf{1 9}} mathbf{C} ) A . ( 2000 V ) в. ( 50 V ) ( mathbf{c} .500 V ) D. ( 1000 V ) |
12 |

753 | What is the nature of Gaussian surface involved in Gauss law of electrostatic? A. Scalar B. Electrical c. Magnetic D. vector |
12 |

754 | The equipotential surface of an electric dipole is: A. A sphere whose centre coincides with the centre of the electric dipole B. A plane surface inclined at an angle of ( 45^{circ} ) with the axis of the electric dipole C. A plane surface passing through the centre of the electric dipole and perpendicular to the axis of the electric dipole D. Any plane surface parallel to the axis of the electric dipole |
12 |

755 | Ordinary rubber is an insulator. But the special rubber tyres of aircrafts are made slightly conducting. Why is this necessary? A. The charged developed due to atmospheric electricity finds its way to the earth B. The charged developed due to friction finds its way to the earth c. The charged developed due to induction finds its way to the earth D. The charged developed due to the aircraft engine finds its way to the earth |
12 |

756 | Explain why the electric field inside a conductor placed in an external electric field is zero. | 12 |

757 | When does an electric dipole placed in a uniform electric field experience a. Maximum Torque b. Minimum Torque |
12 |

758 | A charged body is brought near a positively charged gold leaf electroscopes. The divergence of its leaves increases.What is the kind of charge on the body? A. Positive B. Negative c. Neutral D. Data insufficient |
12 |

759 | Generally, good conductors have low specific heat capacity. True/False? Justify your answer. | 12 |

760 | Potential (in V) at ( r=1.25 mathrm{cm} ) | 12 |

761 | A thinwalled, spherical conducting shel S of radius ( R ) is given charge ( Q ). The same amountof charge is also placed at its centre C. Which of the following statements are correct? This question has multiple correct options A ( cdot ) on the outer surface of ( mathrm{S} ), the charge density is ( frac{Q}{2 pi R^{2}} ) B. The electric field is zero at all points inside c. At a point just outside ( S ), the electric field is double the field at a point just inside D. At any point inside S, the electric field is inversely proportional to the square of its distance from |
12 |

762 | Two equally charged identical metal spheres ( A ) and ( B ) repel each other with a force F. Another identical uncharged sphere ( C ) is touched to ( A ) and then placed midway between ( A ) and ( B ). The net force on ( mathrm{C} ) is in the direction: A. ( F ) towards ( A ) B. ( F ) towards ( mathrm{c} .2 F ) towards ( mathrm{A} ) D. ( 2 F ) towards ( B ) |
12 |

763 | Bulb does not glow when the probs are hanged in air. The reason is: A. air absorbs the electricity B. air is a bad conductor of electricity c. electricity is discharged into air D. air disperses the electricity |
12 |

764 | The black shapes in the figure are closed surfaces. The electric field lines are in red. For which case the net flux through the surfaces is non-zero? (b) ( (c) ) A. In all cases net flux is non-zero B. Only (c) and (d) c. only (a) and (b) D. only (b), (c) and (d) |
12 |

765 | There is an electric field E in x-direction. If the work done on moving a charge of ( 0.2 mathrm{C} ) through a distance of ( 2 mathrm{m} ) along a line making an angle ( 60^{circ} ) with ( x ) -axis is 4 J, then what is the value of E? A. ( sqrt{3} ) N/C B. 4 N/C c. ( 5 mathrm{N} / mathrm{c} ) D. 20 N/C |
12 |

766 | A charge ( q ) is placed at the centre of the line joining two equal charges ( Q ). The system of three charges will be in equilibrium if ( q ) is equal to: A ( cdot-frac{Q}{2} ) в. ( -frac{Q}{4} ) ( c cdot+frac{Q}{4} ) D. ( +frac{Q}{2} ) |
12 |

767 | 1000 small water drops each of radius ( r ) and charge ( q ) coalesce to form one spherical drop. The potential of big drop is larger than that of smaller ones by a factor ( mathbf{A} cdot 1000 ) B. 100 c. 10 D. 1 |
12 |

768 | The electric flux over a sphere of radius ( 1 m ) is ( phi . ) If radius of the sphere were doubled without changing the charge enclosed, electric flux would become ( mathbf{A} cdot 2 phi ) B. ( phi / 2 ) c. ( phi / 4 ) D. |
12 |

769 | ( ln ) a point ( v=-5 x+3 y+sqrt{15} z ) in that point. Find the value of E? | 12 |

770 | A soap bubble of radius ( R ) with wall thickness ( t ) is charged to a potential ( V_{0} ) The bubble bursts and becomesa spherical drop of soap solution of radius ( r . ) Now, it has potential, ( V ) Assume, the soap solution to be a conductor. Then the charge carried by the soap Spherical drop |
12 |

771 | Three charges each of value q are placed at the corners of an equilateral triangle. A fourth charge ( Q ) is placed at the center of the triangle. a. If ( Q=-q, w i | ) the charges at the corners move toward the center or fly away from it b. For what value of ( Q ) at 0 will the charges remain stationary? |
12 |

772 | thin shells of uniformly distributed positive charge ( Q ) and radius ( d ) are located a distance ( 10 d ) from each other. A positive point charge ( q ) is placed inside one of the shells at a distance ( d / 2 ) from the center, on the line connecting the centers of the two shells, as show in the figure. What is the net force on the charge ( q ? ) A ( cdot frac{Q q}{361 pi varepsilon_{0} d^{2}} ) to the left B. ( frac{Q q}{361 pi varepsilon_{0} d^{2}} ) to the right c. ( frac{362 Q q}{361 pi varepsilon_{0} d^{2}} ) to the left D. ( frac{360 Q q}{361 pi varepsilon_{0} d^{2}} ) to the right |
12 |

773 | A short electric dipole moment ( vec{p} ) is placed at a distance ( r ) from the centre of a solid metallic sphere of radius ( a(< ) ( <r) ) as shown in the figure. The electric field intensity at the centre of sphere ( C ) due to induced charge on the sphere is : A. zero B. ( frac{1}{4 pi varepsilon_{0}} frac{2 p}{r^{3}} ) along ( C O ) ( ^{mathbf{C}} frac{1}{4 pi varepsilon_{0}} frac{2 p}{r^{3}} ) along ( O C ) D. ( frac{1}{4 pi varepsilon_{0}} frac{p}{r^{3}} ) along ( C O ) |
12 |

774 | Charge ( Q ), is divided into two parts which are then kept some distance apart. The force between them will be maximum if the two parts are having the charge. ( ^{text {A }} cdot frac{Q}{2} ) each в. ( frac{Q}{4} ) and ( frac{3 Q}{4} ) c. ( frac{Q}{3} ) and ( frac{2 Q}{3} ) D. ( e ) and ( (Q-e) ), where ( e= ) electronic charge |
12 |

775 | (a) Derive a relation for electric field due to an electric dipole at a point on the equatorial plane of the electric dipole. Draw necessary diagram. (b) An electric dipole of charge ( pm 1 mu C ) exists inside a spherical Gaussian surface of radius ( 1 c m ). Write the value of outgoing flux from the Gaussian surface. (c) Potential on the surface of a charged spherical shell of radius ( 10 mathrm{cm} ) is ( 10 V . ) Write the value of potential at ( 5 c m ) from its centre. |
12 |

776 | The direction of induced current in the case lis A. from a to b and from c to d B. from a to b and from fto e ( c . ) from b to a and from d to c D. from b to a and from e to b |
12 |

777 | ( frac{pi}{r_{p}} ) | 12 |

778 | The dimensional formula for electric flux is ( mathbf{A} cdotleft[M L^{3} T^{-3} A^{-1}right] ) B ( cdotleft[M L^{3} T^{-2} A^{-1}right. ) ( mathrm{c} cdotleft[M L^{1} T^{-1} A^{-1}right. ) D ( cdotleft[M L^{4} T^{-2} A^{-1}right] ) |
12 |

779 | Assertion If a positively charged particle is placed in front of a spherical uncharged conductor. The number of lines of forces terminating on the sphere will be more than those emerging from it. Reason The surface charge density at a point on the sphere nearest to the point charge will be negative and maximum in magnitude compared to other points on the sphere A. If both Assertion and Reason are correct and Reason is the correct explanation of Assertion B. If both Assertion and Reason are correct, but Reason is not the correct explanation of Assertion c. If Assertion is correct but Reason is incorrect D. If Assertion is incorrect but Reason is correct |
12 |

780 | A particle ( A ) having a charge of ( 2.0 times ) ( 10^{-6} C ) is held fixed on a horizontal table. A second charged particle of mass ( 80 g ) stays in equilibrium on the table at a distance of ( 10 mathrm{cm} ) from the first charge. The coefficient of friction between the table and this second particle is ( mu=0.2 . ) Find the range within which the charge of this second particle may lie. |
12 |

781 | In column-I some equilibrium or nonequilibrium states are given. In columnII the charges ( +Q ) and ( -Q ) are fixed while charges ( q ) or ( -q ) are moveable point charges as shown in figure. Match the correct options |
12 |

782 | Three concentric conducting spherical shells of radii ( boldsymbol{R}, 2 boldsymbol{R} ) and ( boldsymbol{3} boldsymbol{R} ) carry charges ( Q,-2 Q ) and ( 3 Q, ) respectively Compute the potential at ( r=R ), and the charges on the spheres of radii ( boldsymbol{R} ) and ( 3 R ) A ( cdot frac{Q+2 Q_{1}}{12 pi varepsilon_{0} R}, Q_{1}=frac{Q}{4}, Q_{2}=frac{7 Q}{2} ) в. ( frac{Q+2 Q_{1}}{12 pi varepsilon_{0} R}, Q_{1}=frac{Q}{2}, Q_{2}=frac{7 Q}{2} ) c. ( frac{Q+2 Q_{1}}{12 pi varepsilon_{0} R}, Q_{1}=frac{Q}{2}, Q_{2}=frac{7 Q}{4} ) D. ( frac{Q+2 Q_{1}}{12 pi varepsilon_{0} R}, Q_{1}=frac{Q}{4}, Q_{2}=frac{7 Q}{4} ) |
12 |

783 | Statement 1: A charge is outside the Gaussian sphere of radius ( R ). Then electric field on the surface of sphere is zero Statement 2: As ( oint vec{E} . overrightarrow{d s}=frac{q_{i n}}{varepsilon_{0}}, ) for the |
12 |

784 | Most solid materials are classified as insulators why? A. They offer large resistance to the flow of electric current B. They doesnt do anything c. They offer large force to other particles D. None |
12 |

785 | In a regular polygon of ( n ) sides, each corner is at a distance ( r ) from the centre. Identical charges of magnitude ( q ) are placed at ( (n-1) ) corners. The field at the centre is A. ( _{k^{2}} frac{q}{r^{2}} ) в. ( _{(n-1) k frac{q}{r^{2}}} ) c. ( frac{n}{n-1} k^{frac{q}{r^{2}}} ) D. ( frac{n-1}{n} k frac{q}{r^{2}} ) |
12 |

786 | Let a total charge ( 2 Q ) be distributed in a sphere of radius ( R, ) with the charge density given by ( rho(r)=k r, ) where ( r ) is the distance from the centre. Two charges ( A ) and ( B, ) of ( -Q ) each, are placed on diametrically opposite points, at equal distance, a form the centre. If ( boldsymbol{A} ) and ( B ) do not experience any force, then: A ( cdot a=frac{3 R}{2^{1 / 4}} ) B. ( a=frac{R}{sqrt{3}} ) C ( cdot a=8^{-1 / 4} R ) D . ( a=2^{-1 / 4} R ) |
12 |

787 | Two bodies ( X ) and ( Y ) carry charges ( -6.6 mu C ) and ( -5 mu C ).How many electrons should be transferred from ( X ) and Yso that they acquire equal charges? A ( .2 times 10^{12} ) B . ( 5 times 10^{14} ) ( c cdot 5 times 10^{12} ) D. ( 5 times 10^{13} ) |
12 |

788 | Two small metallic spheres each of mass ( mathrm{m} ) are suspended together with strings of length ( l ) and placed together When a quantum of charge ( boldsymbol{q} ) is transferred to each the strings make an angle of ( 90^{circ} ) with each other. The value of ( q ) is A ( cdot l /left(_{0} m gright) ) в. ( l /left(16_{o} m gright) ) ( mathbf{c} cdot l /left(2_{o} m gright) ) D. none of these |
12 |

789 | A particle of mass ( m ) and negative charge ( q ) is thrown in a gravity free space with speed ( u ) from the point ( A ) in the large nonconducting charged sheet with surface charge density ( sigma, ) as shown in figure. The maximum distance from ( A ) on sheet where the particle can strike is ( frac{boldsymbol{x} epsilon_{0} boldsymbol{u}^{2} boldsymbol{m}}{boldsymbol{q} boldsymbol{sigma}} . ) Find ( boldsymbol{x} ) |
12 |

790 | The number of electrons present in ( 1 C ) of charge is A ( cdot 4.25 times 10^{18} ) B. ( 6.25 times 10^{18} ) c. ( 3.25 times 10^{18} ) D. ( 2.25 times 10^{18} ) |
12 |

791 | A given charge situated at certain distance from an electric dipole in the end on position, experiences a force F. If the distance of charge is doubled, the force acting on the charge will be A ( .2 F ) в. ( F / 2 ) c. ( F / 4 ) D. ( F / 8 ) |
12 |

792 | Electroscope is used A. to detect and test small electric charges B. to calculate the amount of electric charge flowing through the conductor in the given interval of time C. to find out the presence of antimatter D. to test the presence of magnetic field |
12 |

793 | In a gold leaf electroscope, its stem is made up of: A. wood B. brass c. glass D. ebonite |
12 |

794 | Find the magnitude of the force on a charge of ( 12 mu C ) placed at a point where the potential gradient has a magnitude of ( 6 times 10^{5} V m^{-1} ) | 12 |

795 | A non conducting sphere of radius R is filled with uniform volume charge density – ( rho . ) The center of this sphere is displaced from the origin by ( vec{d} ). The electric field ( vec{E} ) at any point ( P ) having position vector inside the sphere is : ( A ) B ( cdot frac{rho}{3 varepsilon_{0}}(vec{r}-vec{d}) ) c. ( frac{rho}{3 varepsilon_{0}}(vec{d}-vec{r}) ) D. ( frac{rho}{3 varepsilon_{0}}(vec{r}) ) |
12 |

796 | Figure shows a charge array known as an electric quadrupole. For a point on the axis of the quadrupole, obtain the dependence of potential on ( r ) for ( r / a>>1 ) and contrast your results with that due to an electric dipole, and an electric monopole (i.e., a single charge). | 12 |

797 | Due to an electric dipole shown in fig., the electric field intensity is parallel to dipole axis ( A cdot ) at ( P ) only B. at Qonly c. both at ( P ) and at ( Q ) D. neither at ( P ) nor at ( Q ) |
12 |

798 | An electric pole of dipole moment ( underset{boldsymbol{p}}{rightarrow} ) is lying along uniform electric field ( overrightarrow{boldsymbol{E}} . ) The work done in rotating the dipole by ( 90^{circ} ) is:- A ( cdot sqrt{2} ) pE B. ( frac{p}{2} ) c. 2 p D. pE |
12 |

799 | If the surface is placed parallel to the electric field, then A. infinite electric flux will pass through the surface B. no electric flux will pass through the surface. c. finite electric flux will pass through the surface. D. variable electric flux will pass through the surface |
12 |

800 | A charged ball B hangs from a silk thread ( S ) which makes an angle ( theta ) with a arge charged conducting sheet ( mathrm{P} ) as shown in the given figure. The surface charge density ( sigma ) of the sheet is proportional to : ( A cdot cos theta ) B ( cdot cot theta ) ( c cdot sin theta ) D. ( tan theta ) |
12 |

801 | What is the S.I. unit of charge? A. Ampere B. Charge c. coulomb D. volt |
12 |

802 | The number of electrons that must be removed from an electrically neutral silver dollar to give it a charge of ( +2.4 C ) is A ( .2 .5 times 10^{19} ) B. ( 1.5 times 10^{19} ) c. ( 1.5 times 10^{-19} ) D. ( 2.5 times 10^{-19} ) |
12 |

803 | In fig., a cone lies in a uniform electric field E. Determine the electric flux entering the cone A. Flux ( phi=E A=2 E R h ) B. Flux ( phi=E A=7 E R h ) c. Flux ( phi=E A=9 E R h ) D. Flux ( phi=E A=E R h ) |
12 |

804 | Induced charge resides at/in the A. bulk of the object B. centre of the object c. surface of the object D. All of the above |
12 |

805 | An electrolyte is: A. a cell B. a metal C. a liquid that conducts electricity D. sugar |
12 |

806 | A charge ( +q ) is fixed to each of three corners of a square. On the empty corner a charge ( Q ) is placed such that there is no net electrostatic force acting on the diagonally opposite charge. Then: A. ( Q=-2 q ) в. ( Q=-2 sqrt{2} q ) c. ( Q=-sqrt{2} q ) D. ( Q=-4 q ) |
12 |

807 | During electrification by friction A. Proton are transferred from one body to another body B. Neutrons are transferred from one body to another body C. Electrons are transferred from one body to another body D. None |
12 |

808 | A solid metallic sphere is placed in a uniform electric field. Which of the curves shown in figure represent the lines of force correctly? ( mathbf{A} cdot(a) ) B. ( (b) ) ( c cdot(c) ) ( mathbf{D} cdot(d) ) |
12 |

809 | A point charge is brought in an electric field. The electric field at a nearby point This question has multiple correct options A. will increase if the charge is positive B. will decrease if the charge is negative c. may increase if the charge is positive D. may decrease if the charge is negative |
12 |

810 | State Gauss’s theorem and state its any ‘two’ applications. |
12 |

811 | Electric charges having same magnitude of electric charge ‘q’, coulombs are placed at ( x=1 mathrm{m}, 2 mathrm{m}, 3 mathrm{m} ) ( 4 m, 8 m, dots dots ) and so on. If any two consecutive charges have opposite sign but the first charge is necessarily positive, what will be the potential at ( x= ) O? A ( cdot frac{2 h q}{3} ) B. zero C. ( frac{1}{4 pi varepsilon_{0}}left(frac{2 q}{3}right) ) D. ( frac{1}{4 pi varepsilon_{0}}(2 q) ) |
12 |

812 | If 10 million electrons are removed from a neutral body, then the charge on the body is : A ( cdot 1.2 times 10^{-12} C ) B. ( +1.6 times 10^{-12} C ) c. ( -1.6 times 10^{-13} C ) D. ( 10^{-12} C ) |
12 |

813 | A point charge ( +boldsymbol{q} & ) mass ( 100 g boldsymbol{m} ) experiences a force of ( 100 N ) at a point at a distance ( 20 mathrm{cm} ) from a long infinite uniformly charged wire. If it is released its speed is ( 20 sqrt{ln x} ) m/ ( s ) when it is at a distance ( 40 mathrm{cm} ) from wire. Find ( boldsymbol{x} ) |
12 |

814 | Two metallic spheres ( A ) and ( B ) kept on insulating stands are in contact with each other. A positively charged rod ( P ) is brought near the sphere ( A ) as shown in the figure. The two spheres are separated from each other, and the rod ( P ) is removed. What will be the nature of charges on spheres ( boldsymbol{A} ) and ( boldsymbol{B} ) ? |
12 |

815 | (a) Consider an arbitrary electrostatic field configuration. A small test charge is placed at a null point (i.e., where ( mathrm{E}= ) 0) of the configuration. Show that the equilibrium of the test charge is necessarily unstable. (b) Verify this result for the simple configuration of two charges of the same magnitude and sign placed a certain distance apart. |
12 |

816 | Obtain the expression for the intensity of electric field near a uniformly charged straight wire of infinite length with the help of Gauss theorem. |
12 |

817 | A cube of side a carries a charge ( q ) each at the corners of a cube.Then the potential at the centre of cube is then going to be A ( cdot frac{8 q}{pi varepsilon_{0} a} ) в. ( frac{4 q}{4 pi varepsilon_{0} a} ) c. ( frac{4 q}{sqrt{3} pi varepsilon_{0} a} ) D. ( frac{2 q}{pi varepsilon_{0} a} ) |
12 |

818 | Which of the following devices is used to detect the presences of a charge on a body? A. Multimeter B. Electroscope c. Angiogram D. Microscope |
12 |

819 | A charge ( Q ) is to be divided into two parts such the force between them is maximum. They should be divided as A ( cdot frac{Q}{4}, frac{3 Q}{4} ) B . ( frac{a}{3}, frac{20}{3} ) c. ( frac{a}{8}, frac{7 Q}{8} ) D. ( frac{Q}{2}, frac{a}{2} ) |
12 |

820 | Specific heat capacity is for conductors of heat and for insulators of heat. A. low, low B. low, high c. high, high D. high, low |
12 |

821 | A solid conducting sphere having a charge ( Q ) is surrounded by an uncharged concentric conducting spherical shell. Let the potential difference between the surface of the solid sphere and that of the outer surface of the shell be ( V ). If the shell is now given a charge of ( -3 Q . ) Find out the new potential difference between the two surface is: ( mathbf{A} cdot V ) B. ( 2 V ) c. ( 4 V ) ( mathbf{D} cdot-2 V ) |
12 |

822 | Consider the electric dipole moment ( (p=2 q a) ) shown in the figure. The electric field at a point ( boldsymbol{P}(boldsymbol{x}, boldsymbol{y}, boldsymbol{0}) ) in the polar coordinate system is : A ( cdot frac{k_{e} p}{r^{3}}[(2 cos theta) hat{r}-(sin theta) hat{theta}] ) B. ( frac{k_{e} p}{r^{3}}[(2 cos theta) hat{r}+(sin theta) hat{theta} ) c. ( frac{k_{e} p}{r^{3}}[-(2 cos theta) hat{r}+(sin theta) hat{theta} ) D. ( frac{k_{e} p}{r^{3}}[-(2 cos theta) hat{r}-(sin theta) hat{theta} ) |
12 |

823 | Find electric field A ( cdot frac{2 m a V^{2}}{e d^{2}} ) B. ( frac{m a V^{2}}{e d^{2}} ) c. ( frac{2 m a V^{2}}{2 e d^{2}} ) D. ( frac{2 m a V^{3}}{e d^{3}} ) |
12 |

824 | If a conductor has ( 10^{8} ) number of electrons, then the total charge of the conductor is: A. ( +1.6 times 10^{-19} mathrm{C} ) В. ( -1.6 times 10^{-19} mathrm{c} ) c. ( +1.6 times 10^{-11} mathrm{c} ) D. ( -1.6 times 10^{-11} mathrm{C} ) |
12 |

825 | An electric dipole is kept in a uniform electric field, it experiences A. a force and a torque B. a force, but no torque c. a torque, but no force D. neither a force nor a torque |
12 |

826 | We have two electric dipoles. Each dipole consists of two equal and opposite point charges at the ends of an insulating rod of length d. The dipoles sit along the ( x ) -axis a distance ( r ) apart, oriented as shown in figure. Their separation ( r>>d ). The dipole on the left: This question has multiple correct options A. wil feel a force to the left B. will feel a force to the right c. will feel a torque trying to make it rotate counterclockwis D. will feel no torque |
12 |

827 | What is a material called, if it does not allow electric current to flow through it? (Conductor, Insulator) |
12 |

828 | In a Helium gas discharge tube every second ( 40 times 10^{18} H e^{+} ) (ions) move towards the right through a cross section of the tube, while n electrons move to the left in the same time. If the current in the tube is ( 8 A ) towards right then ( n=? ) A ( cdot 10 times 10^{18} ) B. 3 ( times 10^{19} ) ( c cdot 3 times 10^{20} ) D. 3 ( times 10^{2} ) |
12 |

829 | A smooth dielectric slab ( A ) of mass ( m ) and dielectric constant ( k ) is placed between the plates of a parallel plate capacitor and connected to another block ( B ) of equal mass ( m ) through a string and pulley arrangement as shown in the figure. The capacitor plates with separation ( delta ) and width ( b ) are connected to a battery of emf ( boldsymbol{E} ) as shown in the figure. The pulley and string are massless and ( boldsymbol{E}=sqrt{frac{boldsymbol{m} boldsymbol{g} boldsymbol{delta}}{boldsymbol{b}(boldsymbol{k}-mathbf{1}) in_{0}}} ) |
12 |

830 | A conducting sphere of radius ( boldsymbol{R} ) having charge ( q ) is joined to another conducting sphere of radius ( 2 R ) having charge ( -2 q . ) The charge flowing between them will be ( mathbf{A} cdot mathbf{q} ) в. ( frac{2 q}{3} ) c. ( frac{q}{3} ) D. ( frac{4 q}{3} ) |
12 |

831 | Consider a neutral conducting sphere. A positive point charge is placed outside the sphere. The net charge on the sphere is then, A. negative and distributed uniformly over the surface of the sphere B. negative and appears only at the point on the sphere closest to the point charge c. negative and distributed non-uniformly over the entire surface of the sphere D. zero |
12 |

832 | Identify the wrong statement. ( A . ) In an electric field two equipotential surfaces can never intersect B. A charged particle free to move in an electric field shall always move in the direction of ( E ) C. Electric field on the surface of a charged conductor is always normal to the surface D. The electric potential decrease along a line of force in an electric an electric field |
12 |

833 | There is a point charge q located at the centre of a cube. What is the electric flux of this point charge, through a face of the cube? A ( cdot frac{q}{epsilon_{0}} ) в. ( frac{q}{6 epsilon_{0}} ) c. ( frac{q}{3 epsilon_{0}} ) D. It will depend on the size of the cube |
12 |

834 | Which of the following charges is/are impossible? A ( cdot 4.8 times 10^{-18} mathrm{C} ) B . ( 5.8 times 10^{-18} mathrm{C} ) c. ( 12.8 times 10^{-18} mathrm{C} ) D . ( 20.8 times 10^{-18} mathrm{C} ) |
12 |

835 | An electron moving with a constant velocity ( v ) along ( X ) -axis enters a uniform electric field applied along Y-axis. Then, the electron moves A. with uniform acceleration along Y-axis B. without any acceleration along Y-axis C ( . ) in a trajectory represented as ( y=a x^{2} ) D. in a trajectory represented as ( y=a x ) E. with uniform deceleration along ( mathrm{x} ) -axis |
12 |

836 | Assertion A small electric dipole is moved translationally from higher potential to lower potential in uniform electric field. Work done by electric field is positive. Reason When a positive charge is moved from |
12 |

837 | If flux in a coil changes by ( Delta phi, ) and the resistance of the coil is ( R ), prove that the charge flown in the coil during the flux change is ( frac{Delta phi}{R} . ) (Note: It is independent of the time taken for the change in flux) | 12 |

838 | The diagram shows a sphere of radius ( boldsymbol{R} ) that carries a charge ( boldsymbol{Q} ) uniformly distributed throughout its volume. ( A ) Gaussian sphere of radius ( a ) is imagined that is concentric to the charged sphere. If ( a<R, ) what is the charge enclosed in the Gaussian surface? ( ^{mathbf{A}} cdot Q_{e n c}=Q frac{a^{4}}{R^{4}} ) ( ^{mathbf{B}} cdot Q_{e n c}=Q frac{a}{R} ) ( ^{mathbf{C}} Q_{e n c}=Q frac{a^{2}}{R^{2}} ) ( ^{mathrm{D}} Q_{e n c}=Q frac{a^{3}}{R^{3}} ) ( ^{mathrm{E}} cdot Q_{e n c}=Q frac{a^{5}}{R^{5}} ) |
12 |

839 | Calculate force on an electron in a uniform electric field of ( 5 times 10^{4} mathrm{N} / mathrm{C} ) due north. |
12 |

840 | Which unit is equivalent to the coulomb?
This question has multiple correct options |
12 |

841 | A point charge ( q ) is at centre of an unchanged spherical conducting shell of inner radius ( a ) and outer radius ( b ) Work needed to move the charge out to infinity will be ( ^{mathbf{A}} cdot frac{q^{2}}{4 pi varepsilon_{0}}left(frac{1}{a}-frac{1}{b}right) ) B. ( frac{1}{8 pi epsilon_{0}} frac{q^{2}}{a} ) ( ^{mathbf{c}} cdot frac{q^{2}}{8 pi epsilon_{0}}left[frac{1}{b}-frac{1}{a}right] ) ( ^{mathrm{D}} cdot frac{q^{2}}{8 pi epsilon_{0}}left[frac{1}{a}-frac{1}{b}right] ) |
12 |

842 | A solid insulating sphere of radius ( boldsymbol{R} ) is given a charge ( Q ). If at a point inside the sphere the potential is 1.5 times the potential at the surface, this point will be: A. at a distance of ( 2 R / 3 ) form the centre B. at the centre c. at a distance of ( 2 R / 3 ) form the surface D. data insufficient |
12 |

843 | A charge is kept at the centre of a shell. Shell has charge Quniformally distibuted over its surface and radius ( mathrm{R} ) The force on the central charge due to the shell is : A. towards left B. towards right c. upward D. zero |
12 |

844 | What is the did charge ( q ) is projected towards an infinitely long line of a charge (having linear density of charge ( +lambda ) ) from a distance ( t_{0} . ) The direction of initial velocity ( v_{0} ) makes an angle ( 30^{circ} ) with the normal to the line of charge as shown in figure. The minimum distance of approach of the charge particle with the line of charge will be (neglect gravity). ( operatorname{take} lambda=frac{pi varepsilon_{0} m v_{0}^{2}}{4 q} ) ( A cdot frac{r_{0}}{e} ) B. ( frac{r_{0}}{e^{2}} ) c. ( frac{r_{0}}{e^{3}} ) D. ( frac{r_{0}}{2} ) |
12 |

845 | Consider 3 identical charges of charge q placed at the vertices of an equilatera triangle, as shown in the figure. What is the force on one of the charges due to the others? ( ^{mathbf{A}} cdot frac{1}{4 pi epsilon_{0}} frac{q^{2}}{l^{2}} ) B. ( frac{sqrt{2}}{4 pi epsilon_{0}} frac{q^{2}}{l^{2}} ) C. ( frac{sqrt{3}}{4 pi epsilon_{0}} frac{q^{2}}{l^{2}} ) D ( cdot frac{2 sqrt{3}}{4 pi epsilon_{0}} frac{q^{2}}{l^{2}} ) |
12 |

846 | Two fixed charges ( A ) and ( B ) of ( 5 mu C ) each are separated by a distance of ( 6 mathrm{m} . mathrm{C} ) is the mid point of the line joining A and B. A charge ‘Q’ of ( -5 mu C ) is shot perpendicular to the line joining A and B through ( C ) with a kinetic energy of 0.06 J. The charge ‘Q’ comes to rest at a point D. The distance CD is? |
12 |

847 | Three charges ( Q,+q ) and ( +q ) are placed at the vertices of a right-angled isosceles triangle between as shown. The net electrostatic energy of the configuration is zero if ( Q ) is equal to ( ^{A} cdot frac{-2 q}{1+sqrt{2}} ) в. ( frac{2 q}{2+sqrt{2}} ) ( c cdot-2 q ) D. ( +q ) |
12 |

848 | An oil drop is negatively charged and weights ( 5 times 10^{-4} N ). The drop is suspended in an electric field intensity of ( 2.6 times 10^{4} N / C ). The number of electrons the oil drop is in ( boldsymbol{x} times mathbf{1 0}^{mathbf{1 0}} ) Then ( x ) is A. 8 B. 10 ( c cdot 16 ) D. 12 |
12 |

849 | Four charges are arranged at the corners of a square ABCD as shown in figure. The force on a positive charge kept at the centre of the square is: A. zero c. along diagonal BD D. perpendicular to the side AB |
12 |

850 | The cube as shown in Fig. has sides of length ( L=10.0 mathrm{cm} . ) The electric field is uniform, has a magnitude ( boldsymbol{E}=mathbf{4 . 0 0} times ) ( 10^{3} N C^{-1}, ) and is parallel to the ( x y- ) plane at an angle of ( 37^{circ} ) measured from the ( +x-a x i s ) towards the ( +y-a x i s ) Electric flux passing through surface ( boldsymbol{S}_{6} ) is A ( cdot 24 N m^{2} C^{-1} ) B. ( -24 N m^{2} C^{-1} ) ( mathbf{c} cdot 32 N m^{2} C^{-1} ) D. ( -32 N m^{2} C^{-1} ) |
12 |

851 | If the symmetry is such that you can find a surface on which the electric field is constant, then evaluating the electric flux can be done by A. dividing the value of the field by the area of the Gaussian surface. B. multiplying the value of the field times the area of the Gaussian surface c. multiplying the square of the value of the field times the area of the Gaussian surface. D. dividing the square of the value of the field times the area of the Gaussian surface |
12 |

852 | A charged particle ‘q’ lies at ‘P’ and the line ( mathrm{PC} ) is perpendicular to the surface of ( A B C ) (part of disc). Find the flux passing through the surface ABC. A ( cdot frac{q}{4 varepsilon_{0}} ) в. ( frac{q}{16 varepsilon_{0}} ) c. ( frac{q}{32 varepsilon_{0}} ) D. ( frac{q}{48 varepsilon_{0}} ) |
12 |

853 | A glass rod rubbed with silk is brought near the fur rubbed with an ebonite rod. What will be your observation between them? A . Attraction B. Repulsion c. No change D. cant say |
12 |

854 | There is a uniform electrostatic field in a region. The potential at various points on a small sphere central at ( P ), in the region, is found to vary between the limits ( 589.0 mathrm{V} ) to ( 589.8 mathrm{V} ). What is the potential at a point on the sphere whose radius vector makes an angle of ( 60^{circ} ) with the direction of the field? A . ( 589.5 mathrm{v} ) B. ( 589.2 v ) c. ( 589.4 mathrm{v} ) D. 589.6 |
12 |

855 | Assertion : Electric lines of force never cross each other. Reason: Electric field at a point superimpose to give one resultant electric field. A. If both assertion and reason are true but the reason is the correct explanation of assertion. B. If both assertion and reason are true but the reason is not the correct explanation of assertion c. If assertion is true but reason is false D. If both the assertion and reason are false. E. If reason is true but assertion is false |
12 |

856 | There are 27 drops of a conducting fluid. Each drop has radius ( r, ) and each of them is charged to the same potential ( V_{1} ).They are then combined to form a bigger drop.The potential of the bigger drop is ( V_{2} ).Find the ratio ( V_{2} / V_{1} ). Ignore the change in density of the fluid on combining the drops. |
12 |

857 | Find the electric field at ( z<-mathbf{0 . 5 d} ) ( mathbf{A} cdot E=0 ) B ( cdot E=-frac{sigma}{epsilon_{0}} hat{k} ) ( mathbf{c} cdot E=frac{sigma}{epsilon_{0}} hat{k} ) D. ( E=frac{sigma}{2 epsilon_{0}} hat{k} ) |
12 |

858 | ( q_{1}, q_{2}, q_{3}, ) and ( q_{4} ) are point charges located at points as shown in the figure and ( mathrm{S} ) is a spherical Gaussian surface of radius R. Which of the following is true according to the Gauss’s law? A ( cdot oint_{5}left(vec{E}_{1}+vec{E}_{2}+vec{E}_{3}right) cdot d vec{A}=frac{q_{1}+q_{2}+q_{3}}{2 varepsilon_{0}} ) B. c. ( oint_{5}left(vec{E}_{1}+vec{E}_{2}+vec{E}_{3}right) cdot d vec{A}=frac{left(q_{1}+q_{2}+q_{3}+q_{4}right)}{varepsilon_{0}} ) D. None of the above |
12 |

859 | The radius of hollow metallic sphere is ( r ) If the potential difference between its surface and a at a distance ( 3 r ) from its centre is v then the electric field intensity at a distance of ( 3 r ) its centre is: A. v/2r B. ( vee / 3 ) r c. ( vee / 4 r ) D. V/6 |
12 |

860 | How does the electric field(E) between the plates of a charged cylindrical capacitor vary with the distance r from the axis of the cylinder? A ( cdot E propto frac{1}{r^{2}} ) в. ( quad E propto frac{1}{r} ) c. ( E propto r^{2} ) D. ( E propto r ) |
12 |

861 | A proton and an electron are placed in a uniform electric field. A. The electric forces acting on them will not be equal. B. The magnitudes of the forces will be equal. C. Their accelerations will be equal. D. None of the above |
12 |

862 | So that the torque acting on it is zero | 12 |

863 | Electric charge is always conserved in physical process. A. True B. False |
12 |

864 | The distance between the two charges ( +q ) and ( -q ) of a dipole is ( r . ) The intensity at a point on the axial line at a distance ( x ) from the centre of dipole is proportional to A ( cdot frac{q}{x^{2}} ) в. ( frac{q r}{x^{2}} ) c. ( frac{q}{x^{3}} ) D. ( frac{q r}{x^{3} r} ) |
12 |

865 | Given a uniform electric field ( overrightarrow{boldsymbol{E}}=mathbf{2} times ) ( 10^{3} hat{i} mathrm{N} / mathrm{C} ). Find the flux of this field through a square of side ( 20 mathrm{cm}, ) whose plane is parallel to the ( y ) -z plane. What would be the flux through the same square, if the plane makes an angle of ( 30^{circ} ) with the ( x ) -axis? |
12 |

866 | Assertion A small power circuit that is isolated from ground typically is less dangerous. Reason Its contacting just one power wire will not form a complete circuit path, and it is too small to collect large dangerous atmospheric charge potentials. A. Both Assertion and Reason are correct and Reason is the correct explanation for Assertion B. Both Assertion and Reason are correct but Reason is not the correct explanation for Assertion C. Assertion is correct but Reason is incorrect D. Both Assertion and Reason are incorrect |
12 |

867 | The rupture of air medium occurs at ( boldsymbol{E}=mathbf{3} times mathbf{1 0}^{mathbf{6}} boldsymbol{V} / boldsymbol{m} . ) The maximum charge that can be given to a sphere of diameter 5 m will be (in coulomb): A ( .2 times 10^{-2} ) B . ( 2 times 10^{-3} ) c. ( 2 times 10^{-4} ) D. ( 2 times 10^{-5} ) |
12 |

868 | The laws of forces that govern the force between two electric charges were discovered by : A. Faraday B. Ampere ( c . ) onm D. Coulumb |
12 |

869 | Two point charges ( +q ) and ( -q ) are held fixed at ( (-d, 0) ) and ( (d, 0) ) respectively of a ( x-y ) coordinate system. Then: A. The electric field ( mathrm{E} ) at all points on the axis has the same direction B. Work has to be done in bringing a test charge from ( infty ) to the orgin C. Electric field at all points on y-axis is along x-axis D. The dipole moment is 2qd along the x-axis |
12 |

870 | If a charge ( q ) is placed at the centre of the line joining two equal charges ( Q ) such that the system is in equilibrium then the value of ( q ) is : A ( . Q / 2 ) в. ( -Q / 2 ) c. ( Q / 4 ) D. ( -Q / 4 ) |
12 |

871 | A cylinder of length ( L ) and radius b has its axis coincident with the x-axis. The electric field in this region is ( overrightarrow{boldsymbol{E}}=mathbf{2 0 0 hat { boldsymbol { i } }} ) Find the flux through the left end of cylinder. ( mathbf{A} cdot mathbf{0} ) в. ( 200 pi b^{2} ) c. ( 100 pi b^{2} ) D. ( -200 pi b^{2} ) |
12 |

872 | A charged rod is brought near a negatively charged pith ball electroscope. What conclusion would you draw about the charge on the rod if pith ball moves away from the rod? A. Positive B. Negative c. No charge D. can’t say |
12 |

873 | A copper ball of radius ( 1 mathrm{cm} ) work function ( 4.47 e V ) is irradiated with ultraviolet radiation of wavelength ( 2500 A ). The effect of irradiation results in the emission of electrons from the ball. Further the ball will require charge and due to this there will be finite value of the potential on the ball. The charge acquired by the ball is: A ( .5 .5 times 10^{-13} mathrm{C} ) В. ( 7.5 times 10^{-13} C ) c. ( 4.5 times 10^{-12} mathrm{C} ) D. ( 2.5 times 10^{-11} C ) |
12 |

874 | If a point lies at a distance ( ^{prime} x^{prime} ) from the mid point of the dipole, the electric potential at this point is proportional to A ( cdot frac{1}{x^{2}} ) B. ( frac{1}{x^{3}} ) c. ( frac{1}{x^{4}} ) D. ( frac{1}{x^{3 / 2}} ) |
12 |

875 | The magnitude of electric force on ( 2 mu c ) change placed at the centre ( O ) of two equilateral triangle each of side ( 10 mathrm{cm} ) as shown in figure is ( P ). If charge ( A, B, C, D, E & F ) are ( 2 mu c, 2 mu c, 2 mu c,-2 mu c,-2 mu c,-2 mu c ) respectively, then ( boldsymbol{P} ) is: A . ( 21.6 N ) B. ( 64.8 N ) ( c ) D. ( 43.2 N ) |
12 |

876 | Four point charges, each of ( +q, ) are rigidly fixed at the four corners of a square planar soap film of side ( a ). The surface tension of the soap film is ( gamma ) The system of charges and planar film are in equilibrium, and ( boldsymbol{a}=boldsymbol{k}left[frac{boldsymbol{q}^{2}}{gamma}right]^{1 / N}, ) where ( k^{prime} ) is a constant. Then ( N ) is: ( A cdot 3 ) B. 2 ( c cdot 4 ) ( D ) |
12 |

877 | Electric intensity is: A . a scalar quantity B. a vector quantity C. neither scalar nor vector D. sometimes scalar and sometimes vector |
12 |

878 | Two point charges ( boldsymbol{q}_{1}=-boldsymbol{4} boldsymbol{mu} boldsymbol{C} ) and ( q_{2}=8 mu C ) are lying on the ( y ) -axis. They are equidistant from the point ( boldsymbol{P} ), which lies on the ( x ) -axis. A small object of charge ( boldsymbol{q}_{0}=8 mu C ) and mass ( boldsymbol{m}=12 boldsymbol{g} ) is placed at ( P . ) When it is released, what is its acceleration in ( m s^{-2} ? ) (Neglect the effect of gravity) B. ( 9 hat{i}+3 sqrt{3} hat{j} ) c. ( 3 hat{i}+3 sqrt{3} hat{j} ) D. ( 3 sqrt{3 i}+3 hat{j} ) |
12 |

879 | There are two unknown charges, ( Q_{1} ) and ( Q_{2} . ) A positive charge is placed at P.P is closer to ( Q_{2} ) than ( Q_{1} ). If the net electric force acting on the charge at P is zero, then conclusion is : [ frac{boldsymbol{rho}_{1}}{mathbf{0}} quad boldsymbol{P} quad underline{boldsymbol{Q}}_{2} ] A. Both ( Q_{1} ) and ( Q_{2} ) are positive B. Both ( Q_{1} ) and ( Q_{2} ) are negative C. Both ( Q_{1} ) and ( Q_{2} ) have opposite signs D. Both ( Q_{1} ) and ( Q_{2} ) have the same sign, but the magnitude of ( Q_{1} ) is greater than the magnitude of ( Q_{2} ) E. ( Q_{1} ) and ( Q_{2} ) have same sign, but the magnitude of ( Q_{2} ) is greater than the magnitude of ( Q_{1} ) |
12 |

880 | Two metallic solid sphere of radii ( mathrm{R} ) and ( 2 R ) are charged such that both of them have same charge density ( sigma ). If the sphere are located far away from each other and connected by a thin conducting wire,the new charge density on bigger sphere is: |
12 |

881 | In filling the gasoline tank of an aeroplane the metal nozzle of the hose from the gasoline truck is always carefully connected to the metal of the aeroplane by a wire before the nozzle is inserted in the tank. Explain, why? |
12 |

882 | A charge ( +mathrm{Q} ) is located in space at the point ( (boldsymbol{x}=mathbf{1} boldsymbol{m}, boldsymbol{y}=mathbf{1 0 m}, boldsymbol{z}=mathbf{5} boldsymbol{m}) ) What is the total electric flux that passes through the yz-plane? A ( cdot frac{Q}{varepsilon_{0}} ) в. ( frac{Q}{3 varepsilon_{0}} ) c. ( frac{Q}{6 varepsilon_{0}} ) D ( cdot frac{Q}{2 varepsilon_{0}} ) |
12 |

883 | Figure shows two conducting spheres separated by large distance and of radius ( 2 mathrm{cm} ) and ( 3 mathrm{cm} ) containing charges ( 10 mu mathrm{C} ) arc ( 20 mu mathrm{C} ) respectively When the spheres are connected by a conducting wire then find out following: ¡)Ratio of the final charge. ii)Final charge on each sphere. iii)Ratio of final charge densities. |
12 |

884 | A unit positive charge is moved along the circumference of a circle due to the attraction of a ( -100 mathrm{C} ) charge at the centre of the circle. Then the work done in the process is A. negative work of 100 J B. positive work of 100 J c. zero D. ( frac{Q .1}{4 pi epsilon_{0} r} ) |
12 |

885 | A small sphere of mass ( m ) and electric charge ( boldsymbol{q}, ) is suspended by a light thread. A second sphere carrying a charge ( q_{2} ) is placed directly below the first sphere at a distance ( ^{prime} d^{prime} ) away. Then A. tension in thread may reduce to zero if the spheres are positively charged B. tension in thread may reduce to zero if the spheres are oppositely charged c. tension in thread can never be zero D. tension in thread is independent of the nature of the charges |
12 |

886 | Figure shows a charge ( q ) placed at the centre of a hemisphere. A second charge ( Q ) is placed at one of the positions ( A, B, C ) and ( D . ) In which position(s) of this second charge, the flux of the electric field through the hemisphere remains unchanged? his question has multiple correct options ( A ) 3. ( c ) ( D ) |
12 |

887 | A point charge ( +10 mu C ) is at a distance 5 ( c m ) directly above the centre of a square of side ( 10 mathrm{cm} ), as shown in the figure. What is the magnitude of the electric flux through the square? A ( cdot 1.2 times 10^{5} mathrm{Nm}^{2} / mathrm{C} ) B . ( 1.9 times 10^{5} mathrm{Nm}^{2} / mathrm{C} ) c. ( 3.2 times 10^{5} mathrm{Nm}^{2} / mathrm{C} ) D. ( 4.2 times 10^{5} mathrm{Nm}^{2} / mathrm{C} ) |
12 |

888 | State whether True or False: In a uniform electric field, the dipole experiences no net force; but experiences a torque having a relation with ( P ) and ( E ) which is given by ( vec{P} times vec{E} ) where the parameters ( P ) and ( E ) have their usual meaning. A. True B. False |
12 |

889 | When a charged rod is brought near the disc of a negatively charged gold leaf electroscope, it is observed that the divergence of leaves decreases.What inference do you draw about the charge on the rod? A. Rod is positively charged B. Rod is negatively charged c. Rod has no charge D. cant say |
12 |

890 | Two short electric dipoles are placed as shown ( ( r ) is distance between their centres). The energy of electric interaction between these dipoles will be: ( left(C text { is centre of dipole of moment } boldsymbol{P}_{2}right) ) ( A ) B. ( -frac{2 k P_{1} P_{2} cos theta}{r^{3}} ) c. ( frac{-2 k P_{1} P_{2} sin theta}{r^{3}} ) D. |
12 |

891 | If both the dipoles are free to rotate about the axes, perpendicular to the plane xoy and passing through 0 and ( A ) respectively, then they will orient themselves such that A ( cdot vec{p}_{1} ) is at right angles to ( vec{p}_{2} ) B. both ( vec{p}_{1} ) and ( vec{p}_{2} ) are along ( overrightarrow{O A} ) c. ( overrightarrow{p_{1}} ) is parallel to ( vec{p}_{2} ) D. ( overrightarrow{p_{1}} ) is antiparallel to ( overrightarrow{p_{2}} ) |
12 |

892 | The electric force on a unit positive charge at a given point in a system of charges is called A . electric dipole moment B. electric field intensity c. electric potential D. electric charge |
12 |

893 | Four particle each having a charge ( boldsymbol{q} ) are placed on the four vertices of a regular pentagon. The distance of each corner from the centre is ( a ). Find the electric field at the centre of the Pentagon. A ( cdot frac{q}{4 pi epsilon_{0} a^{2}} ) Along OE B. ( frac{q}{3 pi epsilon_{0} a^{2}} ) Along OE c. ( Z ) ero D. ( frac{q}{2} ) Along EO |
12 |

894 | Two objects with unlike charges will: A. attract each other B. repel each other C. neither attract nor repel D. either attract or repel |
12 |

895 | Q Type your question charges along the ( x-, y- ) and z-axes, respectively. The charge density, i.e., charge per unit length of each wire is ( lambda: ) A ( cdot frac{lambda}{3 pi varepsilon_{0} a}(hat{i}+hat{j}+widehat{k}) ) В ( cdot frac{lambda}{2 pi varepsilon_{0} a}(hat{i}+hat{j}+widehat{k}) ) c. ( frac{lambda}{2 sqrt{2} pi varepsilon_{0} a}(hat{i}+widehat{j}+widehat{k}) ) D. ( frac{sqrt{2} lambda}{(hat{i}+hat{j}+widehat{k})} ) |
12 |

896 | Identify the correct process that happens here: A. A has gained 2 electrons and B has lost 2 electrons B. A has gained 2 electrons and B has gained 2 electrons C. A has lost 2 electrons and B has gained 2 electrons D. A has lost 2 electrons and ( B ) has lost 2 electrons |
12 |

897 | Coulomb’s law is a confirmation of A. inverse cube law B. product law c. inverse square law D. None of the above |
12 |

898 | A charge ( +10^{-9} C ) is located at the origin in free space and another charge ( Q ) at ( (2,0,0) . ) If the ( X ) -component of the electric field at (3,1,1) is zero, calculate the value of ( Q . ) Is ( Y- ) component zero at (3,1,1)( ? ) |
12 |

899 | When n small drops of a conducting liquid, each of surface charge density ( sigma ) and radius ( r ) are made to combine to form a big drop of radius ( R ), then: A ( . ) potential becomes ( n^{1 / 3} ) times original potential and charge density decreases to ( n^{1 / 3} ) times original charge density B. potential becomes ( n^{2 / 3} ) times and charge density increases to ( n^{1 / 3} ) times original charge density C . potential and charge density decrease to ( n^{4 / 3} ) times original values D. potential and charge density increase to n times original values |
12 |

900 | Four charges ( +boldsymbol{Q},-boldsymbol{Q},+boldsymbol{Q} ) and ( -boldsymbol{Q} ) are situated at the corners of a square; in a sequence then at the centre of the square: A. ( E=0, V=0 ) в. ( E=0, V neq 0 ) c. ( E neq 0, V=0 ) D. ( E neq 0, V neq 0 ) |
12 |

901 | An electric dipole coincides on the zaxis and its centre coincides with the origin of the cartesian coordinate system. The electric field at an axial point at a distance ( z ) from the origin is ( E(z) ) and the electric field at an equatorial point at a distance ( y ) from the origin is ( boldsymbol{E}(boldsymbol{y}) ) Given that ( y=z>>a, ) which is true? A. ( E(z) ) and ( E(y) ) are perpendicular B. ( E(z) ) and ( E(y) ) are parallel C. ( E(z) ) and ( E(y) ) are at ( 45^{circ} ) to one another D. None of these |
12 |

902 | A balloon gets negatively charged by rubbing ceilings of a wall. A. This implies that the wall is positively charged. B. This implies that the wall is negatively charged. C. This does not imply that the wall is positively charged. D. None of these |
12 |

903 | A body has a positive charge of ( 8 x ) ( 15^{-19} C . ) It has A. an excess of ( 5 e^{-} ) B. a deficiency of ( 5 e^{-} ) c. an excess of ( 8 e^{-} ) D. a deficiency of ( 8 e^{-} ) |
12 |

904 | The electric potential at a point on the equatorial line of an electric dipole is : A. directly proportional to distance B. inversely proportional to distance c. inversely proportional to square of the distance D. none of these |
12 |

905 | The Sl unit of electric flux density is A. ( N / C ) в. ( N m^{2} / C ) c. ( N m / C ) D. ( N m^{2} ) |
12 |

906 | Two positive charges ( boldsymbol{q}_{1}=boldsymbol{4} times mathbf{1 0}^{-mathbf{6}} boldsymbol{C} ) and ( q_{2}=9 times 10^{-6} C ) are placed ( 10 mathrm{cm} ) a part in air. The position of a third charge to be placed between them, such that there will be no resultant force on it is: A ( .6 mathrm{cm} ) from ( q_{1} ) B. ( 3 mathrm{cm} ) from ( q_{1} ) c. ( 4 mathrm{cm} ) from ( q_{1} ) D. ( 7 mathrm{cm} ) from ( q_{1} ) |
12 |

907 | A charged oil drop od mass ( 2.5 times ) ( 10^{-7} k g ) is in space between the two plates, each of area ( 2 times 10^{-2} m^{2} ) of a parallel plate capacitor. When the upper plate has a charge of ( 5 times 10^{-7} C ) and the lower plate has an equal negative charge then the oil remains stationery. The charge of the oil drop is (take, ( g= ) ( 10 m / s^{2} ) A ( cdot 9 times 10^{-1} C ) В ( cdot 9 times 10^{-6} C ) C ( .8 .85 times 10^{-13} C ) D. ( 1.8 times 10^{-14} C ) |
12 |

908 | Q Type your question spherical shell that has radius ( R_{2} ) and charge ( Q ) Which of the following changes will increase the capacitance of the system? : Increase the magnitude of the charge, ( Q ) II: Increase ( boldsymbol{R}_{2} ) while leaving ( boldsymbol{R}_{1} ) fixed. III: Increase ( boldsymbol{R}_{1} ) while leaving ( boldsymbol{R}_{2} ) fixed. IV: Increase both R1 and R2 while leaving the difference in radii, ( boldsymbol{R}_{2}-boldsymbol{R}_{1}, ) fixed A. I only B. Il only c. III only D. III and IV only |
12 |

909 | The number of electrons to be removed from a glass rod in order that it acquires a charge of ( 1 mu C ) is: A. ( 6.25 times 10^{12} ) B. ( 10^{12} ) c. ( 6.25 times 10^{13} ) D. ( 10^{13} ) |
12 |

910 | A body is brought near a negatively charged gold leaf electroscope. If the divergence of leaves remains unchanged, state the kind of charge on body in this case. A. positive B. Negative c. no charge D. cant say |
12 |

911 | Two metallic spheres, one hollow and the other solid, have same diameter. The hollow sphere will hold charge A. Same as the solid sphere B. 2 times as the solid sphere ( mathrm{c} cdot frac{1}{2} ) times as the solid sphere D. zero |
12 |

912 | State Gauss law in electrostatics. Using the law derive an expression for electric field due to a uniformly charged thin spherical shell at a point outside the shell. | 12 |

913 | A charge of magnitude ( Q ) is placed at the origin. A second charge of magnitude ( 4 Q ) is placed at the position ( x=d ) along the ( x ) -axis.
Other than infinitely far away, at what position on the ( x ) -axis will a positive test charge experience a zero net force? |
12 |

914 | A metal sphere of radius ( r_{1} ) charged to a potential ( V_{1} ) is then placed in a thin walled uncharged conducting spherical shell of radius ( r_{2} . ) Determine the potential acquired by the spherical shell after it has been connected for short time to a sphere by a conductor. |
12 |

915 | The charge on a sphere of radius ( r ) is ( +Q ) At a point ( P ) which is outside this sphere and at a sufficient distance from it, the electric field is E. Now, another sphere of radius ( 2 mathrm{r} ) and charge ( -2 mathrm{Q} ) is placed with ( P ) as the centre of this second sphere Then, the electric field at the midpoint of the line joining the centres of the two spheres is : A. ( E ) в. ( 4 E ) ( c .6 E ) D. ( 12 E ) |
12 |

916 | Four charges are arranged on y-axis as shown in figure. then the electric field at point ( boldsymbol{P} ) is proportional to: ( A cdot frac{1}{d} ) B. ( frac{1}{d^{2}} ) c. ( frac{1}{d^{4}} ) D. |
12 |

917 | Two copper balls, each weighting ( 10 g ) are kept in air ( 10 mathrm{cm} ) apart. If one electron from every ( 10^{6} ) atom is transferred from one ball to the other, the coulomb force between them is (atomic weight of copper is 63.5 ) A ( cdot 2 times 10^{10} mathrm{N} ) B ( .2 times 10^{4} mathrm{N} ) ( mathbf{c} cdot 2 times 10^{8} mathrm{N} ) D. ( 2 times 10^{6} mathrm{N} ) |
12 |

918 | Compare how the magnitude of the electric field decreases with distance from a uniform charged sphere and a uniform charged wire. A. Both decrease with a one over the square of the distance relationship. B. From the sphere, the electric field decreases with a one over the distance relationship. From the wire, the electric field decreases with a one over the distance squared relationship c. Both decrease with a one over the distance relationship. D. From the wire, the electric field decreases with a one over the distance relationship. From the sphere, the electric field decreases with a one over the distance squared relationship |
12 |

919 | Two identical helium filled balloon ( boldsymbol{A} ) and ( B mathrm{m} ) fastened to a weight of ( 5 g ) by threads floats in equilibrium as shown in fig. Calculate the charge on each balloons, assuming that they carry equal charges |
12 |

920 | An electric dipole is placed in nonuniform electric field, then it experiences A . only torque B. force and torque c. only force D. neither force nor torque |
12 |

921 | A charge ( +mathrm{Q} ) is located in space at point ( (x=1 m, y=10 m, z=5 m) . ) What is the total electric flux that passes through the ( y-z ) plane? A ( cdot frac{Q}{varepsilon_{0}} ) в. ( frac{Q}{3 varepsilon_{0}} ) c. ( frac{Q}{6 varepsilon_{0}} ) D. ( frac{Q}{2 varepsilon_{0}} ) |
12 |

922 | 羊 里 月 卓 | 12 |

923 | Four equal charges, each ( +boldsymbol{q} ) are placed at the corners of a square of side ( a ). Then the coulomb force experienced one charge due to the rest of there is:- ( ^{text {A }} cdot frac{q^{2}}{k a^{2}}left[sqrt{2}+frac{1}{2}right] ) B. ( 3 k q^{2} / a^{2} ) C ( cdot 2 sqrt{2} k q^{2} / a^{2} ) D. zero |
12 |

924 | The charge flowing through a resistance ( R ) varies with time ( t ) as ( Q=a t-b t^{2} ) where a and b are positive constants. The total heat produced in ( boldsymbol{R} ) is: A ( cdot frac{a^{3} R}{6 b b} ) B. ( frac{a^{3} R}{3 b} ) c. ( frac{a^{3} R}{2 b} ) D. ( frac{a^{3} R}{b} ) |
12 |

925 | The electric charge developed on glass rod rubbed with silk cloth is different from the charge developed on ebonite rod rubbed with fur A. True B. False |
12 |

926 | A surface ( d s=10 hat{j} ) is kept in an electric field ( overrightarrow{boldsymbol{E}}=mathbf{2} hat{boldsymbol{i}}+boldsymbol{4} hat{boldsymbol{j}}+7 hat{boldsymbol{k}} . ) How much electric flux will come out through the surface? A . 40 unit B. 50 unit c. 30unit D. 20 unit |
12 |

927 | Consider a uniform electric field ( boldsymbol{E}= ) ( 3 times 10^{3} hat{i} mathrm{N} / mathrm{C} ) (a) What is the flux of this field through a square of ( 10 mathrm{cm} ) on a side whose plane is parallel to the ( y z ) plane? (b) What is the flux through the same square if the normal to its plane makes a ( 60^{circ} ) angle with the ( x ) -axis? |
12 |

928 | Which of the following charging methods work without ever touching the object to be charged to the object used to charge it? A. charging by friction B. charging by contact c. charging by induction D. all of these |
12 |

929 | When a polythene piece is rubbed with wool, it acquires negative charge. A. True B. False |
12 |

930 | Figure shows the electric field lines around an electric dipole. Which of the arrows best represents the electric field at point P? ( A ) 3. ( c ) D |
12 |

931 | The line ( A A^{prime} ) is on a changed infinite conducting plane which is perpendicular to the plane of the paper. The plane has a surface density of charge ( sigma ) and ( mathrm{B} ) is a ball of mass ( mathrm{m} ) with a like charge of magnitude ( q . B ) is connected by a string from a point on the line ( A A^{prime} . ) The tangent of the angle ( (theta) ) formed between the line ( A A^{prime} ) and the string is: A ( cdot frac{q sigma}{2 epsilon_{c} m g} ) В . ( frac{q sigma}{4 pi epsilon theta} m g ) c. ( frac{q sigma}{2 pi epsilon m g} ) D. ( frac{q sigma}{epsilon_{0} m g} ) |
12 |

932 | An electric dipole has a pair of equa and opposite point charges ( +mathrm{Q} ) and ( mathrm{Q} ) separated by a distance 2x. The axis of the dipole is defined as A. the line joining positive charge to -ve charge B. the line making angle of ( 45^{circ} ) with line joining two charges c. perpendicular to the line joining the two charges drawn at the centre and pointing upward direction D. perpendicular to the line joining the two charges drawn at the centre and pointing downward direction |
12 |

933 | An electron enters an electric field with its velocity in the direction of the electric lines of field then: A. the path of the electron will be a circle B. the path of the electron will be a parabola c. the velocity of the electron will decrease just after entry D. the velocity of the electron will increase just after entry |
12 |

934 | respectively, constitute an electric dipole. Distance ( A B=2 a, 0 ) is the mid point of the dipole and OP is perpendicular to AB. A charge Q is placed at ( P ) where ( O P=y ) and ( y>>2 a . ) The charge ( Q ) experiences and electrostatic force F. If ( Q ) is now moved along the equatorial line to ( P^{prime} ) such that ( O P^{prime}= ) ( left(frac{y}{3}right) ) the force on ( Q ) will be close to ( L ) ( left(frac{y}{3}>>2 aright) ) ( A cdot frac{F}{3} ) в. зF ( c . ) 9F D. 27 |
12 |

935 | If the object is not grounded while performing electrostatic induction, the nearby charge will A. induce equal and opposite charges in the object. B. induce equal charges in the object. c. induce opposite charges in the object D. None of the above |
12 |

936 | One-fourth of a sphere of radius R is removed as shown in Fig. An electric field E exists parallel to the xy plane. Find the flux through the remaining curved part : ( mathbf{A} cdot pi R^{2} E ) В. ( sqrt{2} pi R^{2} E ) c. ( pi R^{2} E / sqrt{2} ) D. none of these |
12 |

937 | A long straight charged wire has the electric field measured as ( 5 N / C ) and pointing down at a distance of ( 10 mathrm{cm} ) above it. What would the electric field measure |
12 |

938 | Assertion Gauss law holds good only to those closed surfaces which is enclosing non- zero electric charge. Reason The electric flux through a closed surface is unaltered due to the presence of outside charge. A. Both Assertion and Reason are correct and Reason is the correct explanation for Assertion B. Both Assertion and Reason are correct but Reason is not the correct explanation for Assertion C. Assertion is incorrect but Reason is correct D. Both Assertion and Reason are incorrect |
12 |

939 | Eight small droplets of mercury of equal radii are charged to the same potential ( 10 V ). If they coalesce to form one big drop, the potential on big drop is: A . ( 10 V ) в. ( 20 V ) ( c .30 V ) D. ( 40 V ) |
12 |

940 | Let ( E_{1}(r), E_{2}(r) ) and ( E_{3}(r) ) be the respective electric fields at a distance from a point charge ( Q, ) an infinitely long wire with constant linear charge density ( lambda, ) and an infinite plane with uniform surface charge density ( sigma . ) If ( mathrm{E}_{1}left(r_{0}right)= ) ( E_{2}left(r_{0}right)=E_{3}left(r_{0}right) ) at a given distance ( r_{0} ) then : A ( cdot Q=4 sigma pi r_{0}^{2} ) B . ( r_{0}=frac{lambda}{2 pi sigma} ) c. ( E_{1}left(r_{0} / 2right)=2 E_{2}left(r_{0} / 2right) ) D. ( E_{2}left(r_{0} / 2right)=4 E_{3}left(r_{0} / 2right) ) |
12 |

941 | Two equal charges ‘ ( q ) ‘ of opposite sign are separated by a small distance ‘d’. The electric intensity ‘ ( E ) ‘ at a point on the straight line passing through the two charges at a very large distance ‘ ( r ) ‘ from the midpoint of two charges is : A ( cdot frac{1}{4 pi varepsilon_{0}} frac{q d}{r^{2}} ) В. ( frac{1}{4 pi varepsilon_{0}} frac{2 q d}{r^{2}} ) c. ( frac{1}{4 pi varepsilon_{0}} frac{q d}{r^{3}} ) D. ( frac{1}{4 pi varepsilon_{0}} frac{2 q d}{r^{3}} ) |
12 |

942 | State whether given statement is True or False
Iron is a better conductor of heat than |
12 |

943 | How much time will have elapsed? A ( .1 .42 times 10^{-8} mathrm{s} ) B . ( 2.84 times 10^{-8} mathrm{s} ) c. ( 3.84 times 10^{-8} mathrm{s} ) D. ( 5.68 times 10^{-8} mathrm{s} ) |
12 |

944 | Choose the appropriate option: In metals. than the insulators. A. There are more free electrons B. There are less free electrons c. There are all free electrons D. There are no free electrons |
12 |

945 | State Gauss’s law in electrostatics. | 12 |

946 | An electric dipole (dipole moment ( =p ) ) is placed in a uniform electric field in stable equilibrium position at rest. Now it is rotated by a small angle and released. The time after which it comes to the equilibrium position again (for first time) is ( t . ) Then the moment of inertia of the dipole about the axis of rotation is : A ( cdot frac{4 t^{2} p E}{3 pi^{2}} ) в. ( frac{1 t^{2} p E}{4 pi^{2}} ) c. ( frac{2 t^{2} p E}{3 pi^{2}} ) D. ( _{4} frac{t^{2} p E}{pi^{2}} ) |
12 |

947 | A negatively charged ebonite rod is brought near the glass rod which has been robbed on silk. State your observation between them A . Attraction B. Repulsion c. No change D. cant say |
12 |

948 | If one penetrates a uniformly charged solid sphere, the electric field ( E ) A . increases B. decreases c. is zero at all points D. remains same as at the surface |
12 |

949 | ( A, B ) and ( C ) are three charged bodies. If ( A ) and B repel each other and A attracts C, what is the nature of the force between B and C? |
12 |

950 | The number of electrons for one coulomb of charge are: A ( cdot 6.25 times 10^{23} ) B. ( 6.25 times 10^{21} ) c. ( 6.25 times 10^{18} ) D. ( 6.25 times 10^{19} ) |
12 |

951 | When two charged objects attract each other, the objects carry: A. same charges B. opposite charges c. no charges D. none of the above |
12 |

952 | Assertion Charge can neither be created nor destroyed. Reason Positive Charge attracts negative charge. A. Both Assertion and Reason are correct and Reason is the correct explanation for Assertion B. Both Assertion and Reason are correct but Reason is not the correct explanation for Assertion C. Assertion is correct but Reason is incorrect D. Both Assertion and Reason are incorrect |
12 |

953 | Three infinite planes have a uniform surface charge density ( sigma ) on is surface. All charges are fixed.On each of the three infinite planes parallel to the ( y- ) ( z ) plane placed at ( x=-a, x=0 ) and ( boldsymbol{x}=boldsymbol{a} . ) The potential difference between ( A ) and ( C ) is: ( A ) в. ( frac{sigma}{varepsilon_{0}} ) c. ( frac{sigma a}{2 varepsilon_{0}} ) D. |
12 |

954 | An uncharged metal object ( M ) is insulated from its surroundings. A positively charged metal sphere ( boldsymbol{S} ) is then brought near to ( M . ) Which diagram best illustrated the resultant distributions of charge on ( S ) and ( M ? ) ( A ) в. ( c ) D. |
12 |

955 | Four point charges, each equal to ( q=4 mu C ) are held at the corners of a square ABCD of side ( a=10 mathrm{cm} . ) Find the magnitude and sign of a charge ( Q ) placed at the centers of the square so that the system of charges is in equilibrium. |
12 |

956 | A particle with charge ( e ) and mass ( m ) moving along the X-axis with a uniform speed ( u ), enters a region where a uniform electric field ( E ) is acting along the Y-axis. The particle starts to move in a parabola. Its focal length (neglecting any effect of gravity) is : ( ^{A} cdot frac{2 m u^{2}}{e E} ) в. ( frac{e E}{2 m u^{2}} ) c. ( frac{m u}{2 E} ) D. ( frac{m u^{2}}{2 e E} ) |
12 |

957 | What is the electric potential at the centre of a hemisphere of radius ( mathrm{R} ) and having surface charge density ( sigma ? ) A ( cdot frac{sigma}{2 varepsilon_{0}} ) в. ( frac{sigma}{varepsilon_{0}} ) c. ( frac{sigma}{varepsilon_{0}} R ) D. ( frac{sigma}{2 varepsilon_{0}} R ) |
12 |

958 | A charge ( q ) is placed at 0 in the cavity in a spherical uncharged conductor, Point S is outside the conductor. If q is displaced from 0 towards ( S ) (still remaining within the cavity) A . electric field at S will increase B. electric field at S will decrease c. electric field at ( S ) will first increase and then decreas D. electric field at S will not change |
12 |

959 | Assertion Electric filed of a dipole can’t be found using only Gauss law. (i.e. without using superposition principle) Reason Gauss law is valid only for symmetrical charge distribution A. Both Assertion and Reason are correct and Reason is the correct explanation for Assertion B. Both Assertion and Reason are correct but Reason is not the correct explanation for Assertion c. Assertion is correct but Reason is incorrect D. Assertion is incorrect but Reason is correct |
12 |

960 | Electric flux per unit solid angle is defined as A. Electric force B. Electric field intensity c. Electric potential D. Electric power |
12 |

961 | Two identical metal spheres ( A ) and ( B ) placed in contact are supported on insulating stand. What kind of charge will ( A ) and ( B ) develop when a negatively charged ebonite rod is brought near ( A ) ? |
12 |

962 | A hollow cylinder has a charge ( q ) coulomb within it. If ( phi ) is the electric flux in units of volt-meter associated with the curved surface ( mathrm{B} ), the flux linked with the plane surface A in units of volt-meter will be? |
12 |

963 | If ( E_{a} ) be the electric field intensity due to a short dipole at a point on the axis and ( E_{r} ) be that on the right bisector at the same distance from the dipole, then A ( cdot E_{a}=E_{r} ) В. ( E_{a}=2 E_{r} ) ( mathbf{c} cdot E_{r}=2 E_{a} ) D. ( E_{a}=sqrt{2} E_{r} ) |
12 |

964 | Two free charges ( q ) and ( 4 q ) are placed at a distance d apart. A third charge ( Q ) is placed between them at a distance ( x ) from charges q such that the system is in equilibrium.Then ( A cdot Q=frac{4 q}{9} ) B . ( Q=frac{7 q}{9} ) c. ( Q=-frac{3 q}{9} ) D ( cdot Q=-frac{2 q}{9} ) |
12 |

965 | Let ( A B C ) is a right angled triangle in which ( A B=3 mathrm{cm} ) and ( mathrm{BC}=4 mathrm{cm} ) and ( angle A B C=90^{circ} . ) The three charges +15,+12 and -20 esu are placed on A, B and C respectively. The force acting on B will be A. zero B. 25 dyne c. 30 dyne D. 150 dyne |
12 |

966 | Two charges each of ( +Q ) units are placed along a line. A third charge ( -q ) is placed between them. At what position and for what value of ( q, ) will the system be in equilibrium? |
12 |

967 | A cylinder of radius ( R ) and length Lis placed in the uniform electric field ( mathrm{E} ) parallel to the cylinder axis. The total flux from the curved surface of the cylinder is given by : A ( cdot 2 pi R^{2} E ) в. ( frac{pi R^{2}}{E} ) c. ( frac{pi R^{2}-pi R}{E} ) D. zero |
12 |

968 | Find the charge enclosed in the cylinder A ( cdot 1.1 times 10^{-6} ) В. ( 1.1 times 10^{-9} ) c. ( 1.1 times 10^{-11} ) D. ( 1.1 times 10^{-12} ) |
12 |

969 | Which one of the following is bad conductor of electricity? A. Acid B. coal c. Distilled water D. Human body |
12 |

970 | ( frac{k}{k} ) | 12 |

971 | Explain working of electroscopes? | 12 |

972 | If ( vec{E}_{a x} ) and ( vec{E}_{e q} ) represents electric field at a point on the axial and equatorial line of a dipole. If points are at a distance ( r ) from the centre of the dipole, for ( boldsymbol{r} gg boldsymbol{a} ) ( mathbf{A} cdot overrightarrow{E_{a x}}=overrightarrow{E_{e q}} ) B . ( overrightarrow{E_{a x}}=-overrightarrow{E_{e q}} ) c. ( overrightarrow{E_{a x}}=-2 overrightarrow{E_{e q}} ) D. ( overrightarrow{E_{e q}}=2 overrightarrow{E_{a x}} ) |
12 |

973 | Two charges ( +q ) and ( -q ) are placed at a distance a in a uniform electric field. The dipole moment of the combination is ( 2 q a(cos theta hat{i}+sin theta hat{j}), ) where, ( theta ) is the angle between the direction of the field and the line joining the charges. Which of the following statement(s) is are correct? This question has multiple correct options A. The torque exerted by the field on the dipole vanishes B. The net force on the dipole vanishes c. The torque is independent of the choice of coordinates D. The net force is independent of a |
12 |

974 | The surface area of the drop is: Spherical drop ( mathbf{A} cdot 4 pi R^{2} ) ( mathbf{B} cdot 4 pileft(9 t^{2} R^{4}right)^{1 / 3} ) ( mathbf{C} cdot 4 pileft(9 t^{4} R^{2}right)^{1 / 3} ) D. ( 4 pi R(t+R) ) |
12 |

975 | Which is the biggest physical quantity? A. A coulomb B. Charge on an electron c. charge on a proton D. Charge on a neutron |
12 |

976 | Assertion STATEMENT-1: In a region where uniform electric field exists, the net charge within volume of any size is zero. Reason STATEMENT-2: The electric flux within |
12 |

977 | Flux through the rectangular piece of area ( 10 mathrm{cm} ) by ( 20 mathrm{cm} ) when placed ( (mathrm{as} ) shown in an uniform electric field of ( 200 mathrm{N} / mathrm{C}, ) ) is A ( cdot ) 4.0 ( N m^{2} / C ) B . 3.5 ( N m^{2} / C ) c. ( 2.5 mathrm{Nm}^{2} / mathrm{C} ) D. zer |
12 |

978 | A conducting hollow sphere of radius ( 0.1 mathrm{m} ) is given a charge of ( 10 mu C . ) The electric potential on the surface of sphere will be : A . zero B . ( 3 times 10^{5} V ) ( mathbf{c} cdot 9 times 10^{5} V ) ( mathbf{D} cdot 9 times 10^{9} V ) |
12 |

979 | electric field is along negative ( x ) direction and it is constant. A particle having mass ( m ) and charge ( q ) is projected along ( x ) -direction with speed ( V_{0} . ) An additional force ( overrightarrow{boldsymbol{F}}=overrightarrow{boldsymbol{C}} times overrightarrow{boldsymbol{V}} ) is acting on the charge where ( vec{V} ) is velocity vector and ( vec{C} ) is a constant vector. The charge comes out of region with speed ( boldsymbol{V}_{0} ) ( 2^{text {as shown in figure, then the }} ) magnitude of electric field is : A ( cdot frac{3}{8} frac{m V_{0}^{2}}{q d} ) B. ( frac{4}{3} frac{m V_{0}^{2}}{q d} ) c. ( frac{8}{3} frac{m V_{0}^{2}}{q d} ) D. Can’t be determined |
12 |

980 | Find the electric flux crossing the wire frame ( A B C D ) of length ( I, ) width ( b, ) and center at a distance ( 0 P=d ) from an infinite line of charge with linear charge density ( lambda ). Consider that the plane of the frame is perpendicular to the line OP Fig. A ( cdot frac{2 N}{pi varepsilon_{0}} tan ^{-1}left(frac{b}{2 d}right) ) B. ( frac{N}{pi varepsilon_{0}} tan ^{-1}left(frac{b}{2 d}right) ) c. ( frac{3 N}{pi varepsilon_{0}} tan ^{-1}left(frac{7 b}{2 d}right) ) D. ( frac{N}{2 pi varepsilon_{0}} tan ^{-1}left(frac{b}{2 d}right) ) |
12 |

981 | If an electric field is given by ( 10 hat{i}+ ) ( mathbf{3} hat{boldsymbol{j}}+mathbf{4} hat{boldsymbol{k}}, ) calculate the electric flux through a surface of area 10 units lying in ( boldsymbol{y} boldsymbol{z} ) plane |
12 |

982 | Two particles of masses ( m ) and ( 2 m ) having same charges ( q ) each, are placed in a uniform electric field ( boldsymbol{E} ) and allowed to move for the same time. Find the ratio of their kinetic energies: |
12 |

983 | Two point charges ( (+e) ) and ( (-e) ) are kept inside a large metallic cube without touching its sides. Electric flux emerging out of the cube is? A ( cdot e / varepsilon_{0} ) В. – ( -e / varepsilon_{0} ) c. zero D. ( 2 e / varepsilon_{0} ) |
12 |

984 | Which of the following is an electrica conductor? A. Silver B. Rubber Cork c. Silver-coloured plastic sheet D. woodd |
12 |

985 | A disk with radius R has uniform surface cha disk as a sereis of thin concer potential ( V ) at a point on the di the disk.Assume that the potent A ( cdot frac{sigma}{2 varepsilon_{0}} ) B ( cdot frac{sigma}{30} ) ( c cdot frac{sigma R}{24 c-c} ) D. ( frac{sigma}{66} ) |
12 |

986 | State whether true or false. Pure water is a good conductor of electricity. A. True B. False |
12 |

987 | The length of half wave dipole at ( 15 mathrm{MHz} ) is? ( mathbf{A} cdot 15 mathrm{cm} ) B. ( 12 mathrm{cm} ) c. ( 10 mathrm{cm} ) D. None of these |
12 |

988 | The cube as shown in Fig. has sides of length ( L=10.0 mathrm{cm} . ) The electric field is uniform, has a magnitude ( boldsymbol{E}=mathbf{4 . 0 0} times ) ( 10^{3} N C^{-1}, ) and is parallel to the ( x y- ) plane at an angle of ( 37^{circ} ) measured from the ( +x-a x i s ) towards the ( +y-a x i s ) The total net electric flux through all faces of the cube is ( mathbf{A} cdot 8 N m^{2} C^{-1} ) B. ( -8 N m^{2} C^{-1} ) ( mathbf{c} cdot 24 N m^{2} C^{-1} ) D. zero |
12 |

989 | What is meant by electric flux? Write its S.I. unit and dimensional formula. |
12 |

990 | Total normal electric field = ( mathbf{A} cdot epsilon_{0} vec{E} cdot overrightarrow{d S} ) в. ( vec{E} cdot overrightarrow{d S} ) ( mathbf{c} cdot epsilon_{0} vec{E} ) D. ( epsilon_{0} overline{d S} ) |
12 |

991 | An electric dipole coincides on the zaxis and its centre coincides with the origin of the cartesian coordinate system. The electric field at an axial point at a distance ( z ) from the origin is ( E(z) ) and the electric field at an equatorial point at a distance ( y ) from the origin is ( E(y) ) Given that ( y=z>>a ), the value of |
12 |

992 | An electron is moving round the nucleus of a hydrogen atom in a circular orbit of radius r. The coulomb force ( vec{F} ) between the two is – ( ^{A} cdot_{K} frac{e^{2}}{r^{2}} ) в. ( -K frac{e^{2}}{r^{3}} ) c. ( _{K} frac{e^{2}}{r^{3}} vec{r} ) D. ( -K frac{e^{2}}{r^{2}} ) |
12 |

993 | Two isolated, charged conducting spheres of radii a and b produce the same electric field near their surfaces. The ratio of electric potentials on their surfaces is : A ( cdot frac{a}{b} ) B. ( frac{b}{a} ) c. ( frac{a^{2}}{b^{2}} ) D. ( frac{b^{2}}{a^{2}} ) |
12 |

994 | Electric field at point ( boldsymbol{A} ) depends on ( A ) в. ( q_{2} ) ( c cdot ) both ( q_{1} ) and ( q_{2} ) D. None of these |
12 |

995 | An uncharged insulator can be charged by with another suitable body A. diverging B. induction c. rubbing D. excess |
12 |

996 | For a given surface the Gauss’s law is stated as ( int E cdot d s=0 . ) From this we can conclude that: A. ( E ) is necessarily zero on the surface B. ( E ) is perpendicular to the surface at every point c. the total flux through the surface is zero D. the flux is only going out of the surface |
12 |

997 | Two identical ( +v e ) charges are at the ends of a straight line AB. Another identical ( +v e ) charge is placed at ‘C’ such that ( A B=B C . ) (A, B and C being on the same line). Now the force on ‘A’ will : ( A ). increase B. decrease c. remain same D. cannot be predicted |
12 |

998 | The potential energy of the dipole in the equilibrium position is : ( mathbf{A} cdot+3 times 10^{-23} J ) В. ( -3 times 10^{-23} mathrm{J} ) c. ( -6 times 10^{-23} J ) D. ( -3 times 10^{-36} J ) |
12 |

999 | The process of charging a conductor from a charged body without touching them together is called induction A. True B. False c. Ambiguous D. Data insufficient |
12 |

1000 | Match the following and choose the correct answer. begin{tabular}{lll|l} & Table ( mathbf{A} ) & & Table ( mathbf{B} ) \ a. & conductor & 1. & plastic \ b. & charge at rest & 2. & current electricity \ c. & moving charge & 3. & electrostatic \ d. & insulator & 4. & copper end{tabular} ( mathbf{A} ) ( c-1, d-2, b-3, a-4 ) B . ( d-1, c-2, a-3, b-4 ) c. ( c-4, d-2, b-3, a-1 ) D. ( d-1, c-2, b-3, a-4 ) |
12 |

1001 | The instrument which can be used to detect a charged body is : A. Electroplate B. Leaf electroscope c. Capacitor D. Galvanometer |
12 |

1002 | A point charge ( +Q ) fixed in position, as shown in the diagram. Five points near the charge and in the plane of the page are shown. At which point will an electron experience a force directed toward the top of the page? ( A cdot A ) B. B ( c cdot c ) D. ( E . E ) |
12 |

1003 | Electric charge can not flow through A. insulators B. conductors c. both insulators and conductors D. neither insulators nor conductors |
12 |

1004 | The electricity developed on objects, when they are rubbed with each other is called: A. Frictional potential B. Frictional electricity c. Static electricity D. Static potential |
12 |

1005 | (a) Show that the normal component of electrostatic field has a discontinuity from one side of a charged surface to another given by ( $ $left(E_{-} 21,-right. ) ( mathrm{~ I f r a c { s i g m a ~ } { v a r e p s i l o n ~} ) ( 03 $ $ ) where ( hat{n} ) is a unit vector normal to the surface at a point and ( sigma ) is the surface charge density at that point. (The direction of ( hat{n} text { is from side } 1 text { to side } 2 .) ) Hence show that just outside a conductor, the electric field is ( sigma hat{n} / epsilon_{0} ) (b) Show that the tangential component of electrostatic field is continuous from one side of a charged surface to another. [Hint: For (a), use Gauss’s law. For, (b) use the fact that work done by electrostatic field on a closed loop is zero.] |
12 |

1006 | The ratio of the electric force between two proton to that between two electrons under similar conditions is the order of: ( mathbf{A} cdot 10^{4} ) B. ( 10^{3} ) ( c cdot 10^{36} ) D. |
12 |

1007 | Two conducting charged spheres ( X ) and ( Y ) having unequal charges are connected by the wire. Which of the following is true? A. Charge is conserved B. Electrostatic energy is conserved c. Both the charge and electrostatic energy is conserved D. Neither of these is conserved |
12 |

1008 | The electric dipole is placed along the ( x ) axis at the origin ( O . A ) point ( P ) is at a distance of ( 20 mathrm{cm} ) from this origin such that ( O P ) makes an angle ( 60^{circ} ) with the ( x ) axis. If the electric field at ( P ) makes an angle ( theta ) with the ( x ) -axis, the value of ( theta ) would be A ( cdot frac{pi}{3} ) B. ( tan ^{-1} frac{sqrt{3}}{2} ) c. ( frac{2 pi}{3} ) D. ( frac{pi}{3}+tan ^{-1} frac{sqrt{3}}{2} ) |
12 |

1009 | An electric dipole is placed in a non uniform electric field increasing along the ( + )ve direction of ( mathrm{X} ) – axis. The dipole moves along and rotates A. ( +v e ) direction of ( X ) – axis, clockwise B. – ve direction of ( X ) – axis, clockwise c. ( +v e ) direction of ( X ) – axis, anti clockwise D. – ve direction of ( X ) – axis, anti clockwise |
12 |

1010 | In electric dipole what is the locus of Zero potential? | 12 |

1011 | Calculate the total positive or negative charge on a ( 3.11 g ) copper penny. Given Avogadro number ( =6.02 times 10^{23} ) atomic number of copper ( =29 ) and atomic mass of copper ( =mathbf{6 3 . 5} ) A ( cdot 3.37 times 10^{5} mathrm{C} ) B . ( 2.37 times 10^{5} mathrm{C} ) c. ( 1.37 times 10^{5} C ) D. ( 0.37 times 10^{5} C ) |
12 |

1012 | A spherical metal shell ( A ) of radius ( R_{A} ) and a solid metal sphere ( B ) of radius ( R_{8}left(Q_{B} ) c. ( frac{sigma_{A}}{sigma_{B}}=frac{R_{B}}{R_{A}} ) D. ( E_{A}^{text {on surface}}<E_{B^{text {B }}}^{text {snj }} ) |
12 |

1013 | A copper rod ( A B ) of length ( l ) is rotated about end A with a constant angular velocity ( omega . ) Find electric field at a distance ( x ) from the axis of rotation: A ( cdot frac{m omega^{2} x}{e} ) B. ( frac{m omega x}{e l} ) c. ( frac{m x}{omega^{2} l} ) D. ( frac{m e}{omega^{2} x} ) |
12 |

1014 | State whether true or false. Metals as compared to non-metals are generally bad conductors of electricity. A. True B. False |
12 |

1015 | When a body is charged by induction, then the body A. Becomes neutral B. Does not lose any charge |
12 |

1016 | Dimensional formula for electric field is A ( cdotleft[M L^{2} T^{-3} A^{-1}right] ) B ( cdotleft[M L^{2} T^{-3} A^{-2}right] ) ( mathbf{c} cdotleft[M L T^{-3} A^{-1}right] ) D cdot ( left[M^{0} L^{0} T^{0} A^{0}right] ) |
12 |

1017 | The distance between electron and proton in the H-atom is about 5.3 ( times 10^{-11} ) metre. What is the magnitude of electric force between these two particles? ( left(frac{1}{4 pi varepsilon_{0}}=9 times 10^{9} frac{N m^{2}}{C^{2}}right) ) |
12 |

1018 | Two point charges of charge values ( Q ) and ( q ) are placed at a distance of ( x ) and ( x / 2 ) respectively from a third charge of charge value ( 4 q, ) all charges being in the same straight line. Calculate the magnitude and nature of charge ( Q ) such that the net force experienced by the charge ( q ) is zero. (Assume q is located between charges ( 4 q text { and } Q) ) |
12 |

1019 | A gold leaf electroscope is given a positive charge so that its leaves diverge. How is the divergence of leaves affected, when a positively charged rod is brought near its disc? A. Divergence increases B. Divergence decreases c. Divergence remains same D. can’t say |
12 |

1020 | If ( vec{p}_{2} ) is free to rotate about an axis, perpendicular to the plane and passing through ( A, ) the angle between ( vec{p}_{2} ) and ( vec{p}_{1} ) will be : A ( cdot sin ^{-1}left(frac{1}{3}right) ) ( B cdot tan ^{-1}(3) ) ( mathbf{c} cdot cos ^{-1}left(frac{1}{3}right) ) ( D cdot cot ^{-1}(3) ) |
12 |

1021 | The dipolemoment of the given system is: A. ( sqrt{3} q l ) along perpendicular bisector of ( q-q ) line B. ( 2 q l ) along perpendicular bisector of ( q-q ) line C ( cdot q l sqrt{2} ) along perpendicular bisector of ( q-q ) line D. 0 |
12 |

1022 | Two concentric conducting thin spherical shells have radii a and b ( (a< ) b). If they are charged to ( +Q ) and ( -2 Q ) the graph of electric field as a function of the distance r from center is: A. B. ( c ) D. |
12 |

1023 | Two conductors are of same shape and size. One of copper and the other of aluminium (less conducting) are placed in an uniform electric field. The charge induced in alumintum A. Will be less than that in copper B. will be more than that in copper c. will be equal to that in copper D. cannot be compared with that of copper |
12 |

1024 | An electric dipole moment ( vec{p}=(2.0 hat{i}+ ) ( mathbf{3} .0 hat{boldsymbol{j}}) mu C . mathrm{m} ) is placed in a uniform electric field ( overrightarrow{boldsymbol{E}}=(boldsymbol{3} cdot boldsymbol{0} hat{boldsymbol{i}}+boldsymbol{2} cdot boldsymbol{0} widehat{boldsymbol{k}}) times ) ( mathbf{1 0}^{mathbf{5}} mathbf{N} boldsymbol{C}^{-mathbf{1}} ) This question has multiple correct options A. The torque that ( vec{E} ) exerts on ( vec{p} ) is ( (0.6 vec{i}-0.4 vec{j}- ) ( 0.9 vec{k}) N m ) B. The potential energy of the dipole is ( -0.6 J ) C. The potential energy of the dipole is ( 0.6 J ). D. If the dipole is rotated in the electric field, the maximum potential energy of the dipole is ( 1.3 J ) |
12 |

1025 | Which of the following materials has a negative temperature coefficient of resistance? A. copper B. Aluminium c. carbon D. brass |
12 |

1026 | A point charge q is kept on the vertex of the cone of base radius ( r ) and height ( r ) The electric flux through the curved surface will be ( ^{A} cdot frac{q}{2 varepsilon_{0}}left(1-frac{1}{sqrt{2}}right) ) В ( cdot frac{q}{varepsilon_{0}}left(frac{1}{2 sqrt{2}}right) ) ( c . ) zer D. ( frac{q}{varepsilon_{0} sqrt{2}} ) |
12 |

1027 | An electric dipole consists of two opposite charges each of magnitude ( 1.6 times 10^{-19} ) coulomb at separation 1 Armstrong. The diploe moment is: A ( cdot 1.6 times 10^{-19} c-m ) В. ( 1.6 times 10^{-29} c-m ) c. ( 3.2 times 10^{-29} c-m ) D. ( 3.2 times 10^{-19} mathrm{C}-mathrm{m} ) |
12 |

1028 | On rubbing a glass rod with silk cloth, ( 6.84 times 10^{16} ) electrons are transferred from glass rod to silk cloth. Find the total charge transferred. |
12 |

1029 | A neutral water molecules ( left(H_{2} Oright) ) in its vapour state has an electric dipole moment of ( 6 times 10^{-30} mathrm{Cm} . ) If the molecule is placed in an electric field of ( 1.5 times 10^{4} N C^{-1}, ) the maximum torque that the field can exert on it is nearly: A ( .4 .5 times 10^{-26} mathrm{Nm} ) B. ( 4 times 10^{-34} mathrm{Nm} ) c. ( 9 times 10^{-26} mathrm{Nm} ) D. ( 6 times 10^{-26} mathrm{Nm} ) |
12 |

1030 | State whether true or false. Copper is a poor conductor of electricity as compared to glass. A. True B. False |
12 |

1031 | A piece of paper appears to be attracted to a charged ebonite rod, even before they touch (see fig.). The charge at B is: A. positive B. may be positive or negative c. no charge D. negative |
12 |

1032 | A certain charge ( Q ) is divide at first into two parts ( (q) ) and ( (Q-q) . ) Later on the charges are placed at a certain distance. If the force of interaction between the two charges is maximum then: A ( cdot(Q / q)=(4 / 1) ) B cdot ( (Q / q)=(2 / 1) ) c. ( (Q / q)=(3 / 1) ) D・ ( (Q / q)=(5 / 1) ) |
12 |

1033 | A point charge ( +Q ) having mass ( m ) is fixed on horizontal smooth surface. Another point charge having magnitude ( +2 Q & ) mass ( 2 m ) is projected horizontally towards the charge ( +mathrm{Q} ) from the distance with velocity ( V_{0} ) Force applied by floor on the fixed charge in horizontal direction, when distance between charges becomes ‘d’ A ( cdot frac{2 K Q^{2}}{d^{2}} ) B. ( frac{K Q^{2}}{d^{2}} ) c. zero D. none |
12 |

1034 | A hollow half cylinder surface of radius R and length I is placed in a uniform electric field ( vec{E} ). Electric field is acting perpendicular on the ABCD. If the flux through the curved surface of the hollow cylindrical surface is ( boldsymbol{E} times boldsymbol{X} boldsymbol{R} boldsymbol{l} ). Find ( mathbf{X} ) ? |
12 |

1035 | Consider two statements: A) The force with which two charges interact is not changed by the presence of the other charges. B) Electric force experienced by the charge particle due to number of fixed point charges is vector resultant of the forces experience due to individual charge. ( A ). Both ( A ) and ( B ) are correct B. Only A is correct C. Only B is correct D. Both A and B are wrong |
12 |

1036 | Derive an expression for electric field intensity due to an electric dipole at a point on its axial line. | 12 |

1037 | A long charged cylinder of linear charged density ( lambda ) is surrounded by a hollow co-axial conducting cylinder. What is the electric field in the space between the two cylinders? |
12 |

1038 | An electric dipole consists of two oppositecharges of magnitude ( 1 mu mathrm{C} ) separated by a distanceof 2cm. The dipole is placed in an electric filed ( 10^{-5} mathrm{Vm}^{-1} . ) The maximum torque does the field exerton the dipole is ( mathbf{A} cdot 10^{-3} mathrm{Nm} ) В. ( 2 times 10^{-13} mathrm{Nm} ) c. ( 3 times 10^{-13} mathrm{Nm} ) D. ( 4 times 10^{-13} mathrm{Nm} ) |
12 |

1039 | The electric field intensity at ( boldsymbol{P} ) and ( boldsymbol{Q} ) in the shown arrangement: |
12 |

1040 | The acceleration of a charged particle in a uniform electric field is : (where specific charge of a particle ( left.=frac{q}{m}right) ) A. proportional to its charge only B. inversely proportional to its mass only C. proportional to its specific charge D. inversely proportional to specific charge |
12 |

1041 | A balloon gets negatively charged by rubbing ceilings of a wall. A. The balloon sticks to the ceiling forever. B. The balloon eventually fall off the ceiling C. The balloon does not stick to the ceiling at all D. The balloon charges the ceiling negatively |
12 |

1042 | The ratio of electric force between two electrons to that between two protons separated by the same distance in air is A ( cdot 10^{circ} ) B. ( 10^{6} ) ( c cdot 10^{4} ) D. None of the above |
12 |

1043 | R with centre at the origin, carrying uniform positive surface charge density. The variation of the magnitude of the electric field ( |vec{E}(r)| ) and the electric potential ( V(r) ) with the distance from the centre, is best represented by which graph? ( A ) B. ( c ) D. |
12 |

1044 | toppr Q Type your question ‘8 center of the sphere according to the equation ( =C r . ) The diagram also shows the cross-section of a Gaussian sphere of radius ( a ) that is concentric with the charged sphere Which of the following expresses the |
12 |

1045 | Ten charges having charge ( mathbf{1} mu C, 8 mu C, 27 mu C, dots dots 1000 mu C ) are placed on the ( x ) -axis with co-ordinates ( boldsymbol{x}=mathbf{1} boldsymbol{m}, mathbf{2} boldsymbol{m}, mathbf{3} boldsymbol{m}, mathbf{4} boldsymbol{m}, dots . . mathbf{1 0} boldsymbol{m} . ) The net electric field intensity at the origin is: A ( cdot 9 times 10^{5} N / C ) в. ( 9 times 10^{4} N / C ) C ( .4 .95 times 10^{-5} mathrm{N} / mathrm{C} ) D. ( 4.95 times 10^{5} N / C ) |
12 |

1046 | A charge ( Q ) is distributed over two concentric hollow spheres of radii ( a ) and ( b(a>b), ) so that the surface charge densities are equal. The potential at the common centre is ( frac{1}{4 pi epsilon_{0}} ) times A ( cdot k Qleft(frac{a+b}{a^{2}+b^{2}}right) ) в. ( 2 Qleft(frac{a+b}{a^{2}+b^{2}}right) ) ( c cdot Q ) D. ( frac{Q}{2}left(frac{a+b}{a^{2}+b^{2}}right) ) E ( cdot frac{Q}{4}left(frac{a+b}{a^{2}+b^{2}}right) ) |
12 |

1047 | Consider two points 1 and 2 in a region outside a charged sphere. Two points are not vary far away from the sphere. If ( boldsymbol{E} ) and ( boldsymbol{V} ) represent the electric field vector and the electric potential, which of the following is not possible? A ( cdotleft|vec{E}_{1}right|=left|vec{E}_{2}right|, V_{1}=V_{2} ) в. ( left|vec{E}_{1}right| neqleft|vec{E}_{2}right|, V_{1} neq V_{2} ) c ( cdotleft|vec{E}_{1}right| neqleft|vec{E}_{2}right|, V_{1}=V_{2} ) D . ( left|vec{E}_{1}right|=left|vec{E}_{2}right|, V_{1} neq V_{2} ) |
12 |

1048 | An electron is released from rest in a uniform electric field which causes it to accelerate toward the top of the screen What is the direction of the electric field? A. To the left B. Toward the top of the screen c. To the right D. Toward the bottom of the screen |
12 |

1049 | Which of the following is best insulator? A. carbon B. paper c. ebonite D. graphite |
12 |

1050 | Electric field strength due to a point charge of ( 5 mu C ) at a distance of ( 80 mathrm{cm} ) front he charge is A ( cdot 8 times 10^{4} N / C ) в. ( 7 times 10^{4} mathrm{N} / mathrm{C} ) C ( .5 .55 times 10^{4} N / C ) D. ( 4 times 10^{4} N / C ) |
12 |

1051 | In a region where intensity of electric field is ( 5 N C^{-1}, 40 ) lines of electric force are crossing per square metre. The number of lines crossing per square metre where intensity of electric field is ( 10 N C^{-1} ) will be: A . 20 B. 80 c. 100 D. 200 |
12 |

1052 | A laser beam of pulse power ( 10^{12} W ) is focussed on an object of area ( 10^{-4} mathrm{cm}^{2} ) The energy flux in ( W / c m^{2} ) at the point of focus is A ( cdot 10^{4} ) B. ( 10^{8} ) ( mathbf{c} cdot 10^{16} ) D. ( 10^{20} ) |
12 |

1053 | Two positive point charges of unequal magnitude are placed at a certain distance apart. A samll positive test charge is placed at null point, then: A. Charge is in equilibrium. B. A test charge is in stable equilibrium c. The test charge is in neutral equilibrium D. The test charge is in unstable equilibrium |
12 |

1054 | The force between two charges in different media are different because. B. Different media have different viscosities c. Different media have different densities D. Different media have different permeabilities |
12 |

1055 | How many electrons should be removed from a coin of mas ( 1.6 mathrm{g} ), so that it may float in an electric field of intensity ( 10^{9} ) N/C directed upward? A ( .9 .8 times 10^{7} ) B . ( 9.8 times 10^{5} ) ( mathbf{c} cdot 9.8 times 10^{3} ) D. ( 9.8 times 10^{1} ) |
12 |

1056 | A redistribution of electrical charge in an object, caused by the influence of nearby charges is termed as A. electric conduction B. ionisation c. electrostatic induction D. electromagnetic induction |
12 |

1057 | The parallel plate capacitors with different distance between the plates are connected in parallel to voltage source as shown in the figure. A point positive charge is moved from a point that is exactly in the middle between the plates of the capacitor ( c_{1} ) to a point 2 in capacitor ( c_{2} ) that lies at the plates of ( c_{1} ). Then the work done by the electric force is. A. positive B. negative c. zero D. data insufficient. |
12 |

1058 | A conic surface is placed in a uniform electric field ( E ) as shown in Fig. such that the field is perpendicular to the surface on the side ( A B ). The base of the cone is of radius ( R, ) and the height of the cone is h. The angle of the cone is ( theta ). Find the magnitude of the flux that enters the cone’s curved surface from the left side. Do not count the outgoing flux ( left(theta<45^{circ}right) ) A ( . E R[h cos theta+pi(R / 2) sin theta ) B. ( E R[h sin theta+pi R / 2 cos theta] ) c. ( E R[h cos theta+pi R sin theta ) D. none of these |
12 |

1059 | A charge of ( 4 times 10^{-8} C ) is uniformly distributed over the surface of sphere of radius ( 1 mathrm{cm} . ) Another hollow sphere of radius ( 5 mathrm{cm} ) is concentric with the smaller sphere. Find the intensity of the electric field ( left(text { in } N C^{-1}right) ) at a distance ( 2 c m ) from the centre. ( k=9 times 10^{-9} S I ) |
12 |

1060 | A Force ( F ) is put on a test charge ( Q ) by an electric field. What is the strength of the electric field at that location? A ( cdot frac{Q}{F} ) в. ( frac{F}{Q} ) c. ( F Q ) D. ( F Q^{2} ) |
12 |

1061 | Electric field outside a long wire carrying charge q is proportional to: A ( cdot frac{1}{r} ) в. ( frac{1}{r^{2}} ) c. ( frac{1}{r^{frac{1}{35}}} ) D. ( frac{1}{r^{frac{1}{32}}} ) |
12 |

1062 | When two objects are rubbed against each other they A. will loose electrons B. will repel electrons c. will attracts each other D. may attract or repel each other |
12 |

1063 | A radioactive material is in the form of a sphere whose radius is ( 9 times 10^{-3} ) m. If ( 6.25 times 10^{12} beta^{-} ) particles are emitted per second by it then in how much time will a potential of 1 volt be produced on the sphere if it is isolated? A . ( 1.1 mathrm{ms} ) B . ( 10^{-8} mathrm{ms} ) c. ( 1.0 mu s ) D. 11 mus |
12 |

1064 | Assertion The flux of electric field through a spherical surface of radius 1.5 a is more than flux of electric field through a spherical surface of radius 0.5 a. (Both centred at origin) Reason The electric field at ( x=1.5 ) a is more than electric field at 0.5 a A. Both Assertion and Reason are correct and Reason is the correct explanation for Assertion B. Both Assertion and Reason are correct but Reason is not the correct explanation for Assertion C. Assertion is correct but Reason is incorrect D. Assertion is incorrect but Reason is correct |
12 |

1065 | When an electron moves in a circular path around a stationary nucleus charge at the center: This question has multiple correct options |
12 |

1066 | The Gaussian surface for calculating the electric field due to a charge distribution is A. any closed surface around the charge distribution B. any surface near the charge distribution c. a spherical surface D. a closed surface at a every point of which electric field has a normal component which is zero or a fixed value |
12 |

1067 | Arrange electron(e), proton (p) and deuteron(d) in the increasing order of their specific charge: A ( . e>p<d ) B. ( d<pe>d ) D. ( d>e>p ) |
12 |

1068 | What is the direction of the electric field directly to the east of an isolated negative point charge? A. North B. South ( c . ) East D. west E. Up |
12 |

1069 | State whether the given statement is True or False : Conductors when charged transfer all |
12 |

1070 | The electric field within the nucleus is generally observed to be linearly dependent on ( r . ) This implies. A ( . a=0 ) B. ( a=frac{R}{2} ) ( mathbf{c} cdot a=R ) D ( a=frac{2 R}{3} ) |
12 |

1071 | A point charge ( boldsymbol{q}=mathbf{1 0 0} mu boldsymbol{C} ) is located in the ( x ) -y plane at the point with position vector ( vec{r}_{0}=2 hat{i}+3 hat{j}+hat{k} . ) What is the electric field vector(in ( mathrm{kV} / mathrm{m} ) ) at the point with position vector ( vec{r}=8 hat{i}- ) ( mathbf{5} hat{boldsymbol{j}}+hat{boldsymbol{k}} ? ) ( mathbf{A} cdot 4 cdot 2 hat{i}-5.6 hat{j} ) в. ( 6 hat{i}-8 hat{j} ) c. ( 54 hat{i}-72 hat{j} ) D. ( 5.4 hat{i}-7.2 hat{j} ) |
12 |

1072 | Three charges ( +4 q, Q ) and ( q ) are placed in a straight line of length I at points at distances ( 0,1 / 2, ) and I respectively. What should be ( Q ) in order to make the net force on q to be zero? ( A cdot-q ) B. -29 ( c cdot-frac{q}{2} ) D. 49 |
12 |

1073 | The electric potential at a point ( boldsymbol{P} ) inside a uniformly charged conducting sphere of radius ( R ) and charge ( Q ) at a distance ( r ) from the centre is : A . 0 B . ( infty ) c. ( frac{Q}{4 pi epsilon_{0} r} ) D. ( frac{Q}{4 pi epsilon_{0} R} ) |
12 |

1074 | Two point charge -q and +q/2 are situated at the origin and the point ( (a, 0,0) ) respectively. The point along the X-axis where the electric field vanishes is A ( cdot x=frac{a}{sqrt{2}} ) В. ( x=sqrt{2} a ) c. ( x=frac{sqrt{2} a}{sqrt{2}-1} ) D. ( x=frac{sqrt{2} a}{sqrt{2}+1} ) |
12 |

1075 | A hollow chaeged mental sphere has radius ( r . ) if the potential difference between its surface and a point at a distance ( 3 r ) from the center is ‘v’ then electric field intensity at a distance 3 r is A ( cdot frac{v}{2 r} ) B. ( frac{v}{3 r} ) c. ( frac{v}{6 r} ) D. ( frac{v}{4 r} ) |
12 |

1076 | If a body is positively charged, then it has A. Excess of electrons B. Excess of protons c. Deficiency of electrons D. Deficiency of neutrons |
12 |

1077 | Five balls, numbered 1 to ( 5, ) are suspended using separate threads. Pairs (1,2),(2,4),(4,1) show electrostatic attraction, while pairs (2,3) and (4,5) show repulsion therefore ball 1 must be: A. Positively charged B. Negatively chargedd c. Neutral D. Made of metal |
12 |

1078 | Write the expression for electric intensity at a point due to point charge and explain the terms. | 12 |

1079 | The self potential energy of hydrogen chloride whose dipole moment is ( 3.44 times ) ( 10^{-20} mathrm{Cm} ) and separation between hydrogen and chlorine atoms is ( 1.01 times ) ( 10^{-10} mathrm{m} ) is: В. ( 3.2 times 10^{5} J ) c. ( 4.5 times 10^{7} J ) D. ( 1.65 times 10^{6} J ) |
12 |

1080 | A polished, silvery surface is a: A. Good absorber and good reflector of heat B. Good absorber and bad radiator of heat C. Poor absorber and good reflector of heat D. Poor reflector and good radiator of heat |
12 |

1081 | The electric field between the plates of two oppositely charged plane sheets of charge density’ ( sigma^{prime} ) is : A ( cdot+frac{sigma}{2 epsilon_{0}} ) в. ( -frac{sigma}{2 epsilon_{0}} ) c. ( frac{sigma}{epsilon_{0}} ) D. zero |
12 |

1082 | Ordinary tap water conducts electric current due to : A. the dissolved salts in it it B. higher purity of the water c. the bacteria present in it it D. none of these |
12 |

1083 | In the nucleus of helium, if ( F_{1} ) is the net force between two protons, ( F_{2} ) is the net force between two neutrons and ( F_{3} ) is the net force between a proton and a neutron. Then A ( cdot F_{1}=F_{2}=F_{3} ) в. ( F_{1}>F_{2}>F_{3} ) c. ( F_{2}>F_{3}>F_{1} ) D. ( F_{2}=F_{3}>F_{1} ) |
12 |

1084 | Pictured above is a red point charge and a blue point charge. The blue point charge is moved from loication 1 to location 2. The force between the point charges is ( 5.00 mathrm{N} ) when blue charge is at location 1 How much force exist between the point charges when the blue charges is at location 2? A . 25.0 B. 30.0 N c. ( 125 mathrm{N} ) D. ( 180 mathrm{N} ) E . ( 1.0 mathrm{N} ) |
12 |

1085 | For spherical symmetrical charge distribution, variation of electric potential with distance fro center is given in diagram. Given that ( : V= ) ( frac{boldsymbol{q}}{mathbf{4} boldsymbol{pi} varepsilon_{0} boldsymbol{R}_{0}} ) for ( boldsymbol{r} leq boldsymbol{R}_{0} ) and ( boldsymbol{v}=frac{boldsymbol{q}}{boldsymbol{4} boldsymbol{pi} varepsilon_{0} boldsymbol{r}} ) for ( boldsymbol{r} geq boldsymbol{R}_{0} ) Then which option (s) are correct: This question has multiple correct options A. Total charge within ( 2 R_{0} ) is 9 B. Total electrostatic energy for ( r leq R_{0} ) is non-zer c. ( A t r=R_{0} ) electric field is discontinuous D. There will be no charge anywhere except at ( r<R_{0} ) |
12 |

1086 | A positive test charge is released from rest in a uniform electric field. Which of the following best describes its initial motion? A. It will move with constant velocity along an equipotential line B. It will move with constant acceleration along an equipotential line c. It will move with constant acceleration along an electric field line D. It will move with constant velocity along an electric field line |
12 |

1087 | The safety fuse should have A. high resistance and high melting point B. high resistance and low melting point C. low resistance and high melting point D. low resistance and low melting point |
12 |

1088 | An inclined plane making an angle ( 30^{circ} ) with the horizontal is placed in a uniform horizontal electric field of ( 100 V m^{-1} . ) A particle of mass ( 1 k g ) and charge ( 0.01 C ) is allowed to slide down from rest from the top of the inclined plane. If the coefficient of friction is 0.2 the particle reaches the bottom of the inclined plane in 1 second. Then the length of the inclined plane is (Acceleration due to gravity ( =10 m s^{-2} ) ) A ( .1 .150 m ) в. ( 1.323 m ) c. ( 1.151 m ) D. ( 1.172 m ) |
12 |

1089 | A charge of +2 nC is separated from a charge of ( -2 mathrm{nC} ) by ( 1.5 mathrm{cm} ) forming an electric dipole. What torque acts on the dipole moment vector makes an angle of ( 30^{0} ) in the clockwise sense with the field of magnitude ( 5000 mathrm{N} / mathrm{C} ? ) |
12 |

1090 | The charge on an electron was calculated by: A. Faraday B. J.J Thompson c. Millikan D. Einstein |
12 |

1091 | In a region of space, the electric field is given by ( overrightarrow{boldsymbol{E}}=mathbf{8} hat{mathbf{i}}+mathbf{4} hat{mathbf{j}}+mathbf{3} hat{boldsymbol{k}} . ) The electric flux through a surface of area 100 units in the xy plane is : A. 800 units B. 300 units c. 400 units D. 1500 units |
12 |

1092 | There are two non conducting spheres having uniform volume charge densities ( rho ) and ( -rho . ) Both spheres have equal radius R. The spheres are now laid down such that they overlap as shown in the figure. The electric field ( overrightarrow{boldsymbol{E}} ) in the overlap region is : A. non uniform B. zero c. ( frac{rho}{3 epsilon_{0}} vec{d} ) |
12 |

1093 | When a glass rod is rubbed with a piece of silk cloth the rod ( A cdot ) and the cloth both acquire positive charge B. becomes positively charged while the cloth has a negative charge ( mathrm{C} ). and the cloth both acquire negative charge D. becomes negatively charged while the cloth has a positive charge |
12 |

1094 | Four particles, each having charge ( boldsymbol{q} ) are placed at four verticals of a regular pentagon. The distance of each corner from the center is ( a ). The electric field at the center ( O ) of the pentagon is: A ( cdot frac{q}{4 pi epsilon_{0} a^{4}} ) along ( E O ) B. ( frac{q}{2 pi epsilon_{0} a^{2}} ) along ( E O ) c. ( frac{q}{pi epsilon_{0} a^{2}} ) along ( E O ) D. ( frac{q}{4 pi epsilon_{0} a^{2}} ) along ( E O ) |
12 |

1095 | Complete the following statements with an appropriate word /term be filled in the blank space(s). The force of attraction or repulsion between two charges is given by A. Gauss’s law B. Kepler’s law c. Coulomb’s law D. Gravitational law |
12 |

1096 | Four charges are arranged at the corners of a square ( mathrm{ABCD} ) as shown in the figure. If a test charge is placed at the centre calculate the direction of net force on that charge. A. zero B. along the diagonal AC c. along the diagonal BD D. perpendicular to side AB |
12 |

1097 | A molecule with a dipole moment p is placed in electric field of strength E. Initially the dipole is aligned parallel to the field. If the dipole is to be rotated to be anti parallel to the field, the work required to be done by an external agency is A . – 2pE B . -pE c. pE D. 2pE |
12 |

1098 | Two ball ( A ) and ( B ) of same mass ( (M) ) and charges ( Q,-Q ) are suspended by two strings of same length from two different suspension points ( S_{1} ) and ( S_{2} ) if ( S_{1} S_{2}=3 x ) and ( A B=x ) then show that tension in the string is ( T=frac{Q^{2} L}{4 pi in_{0} x^{3}} ) ( tan theta=frac{Q^{2}}{4 pi in_{0} x^{2} M g} ) |
12 |

1099 | Four positive charges ( (2 sqrt{2}-1) Q ) are arranged at the four corner of a square. Another charge q is placed at the centre of the square. Resulting force acting on each corner charge is zero if q is : A ( cdot frac{-7 Q}{4} ) в. ( frac{-4 Q}{7} ) ( c cdot-Q ) D. ( -(sqrt{2}+1) Q ) |
12 |

1100 | Find the maximum intensity ( mathrm{E}_{max } ) and the corresponding distance ( r_{m} ) |
12 |

1101 | State one activity to prove that air is a bad conductor of electricity | 12 |

1102 | The figure shows schematic field lines resulting from interaction between A . two positive charges B. two negative charges c. a positive and a negative charge D. None of these |
12 |

1103 | Two metallic spheres ( A ) and ( B ) are made of same material and have got an identical surface finish. The mass of sphere ( mathbf{A} ) is four times that of ( mathbf{B} . ) Both the spheres are heated to the same temperature and placed in a room having a lower temperature but thermally insulated from each other. A. The ratio of heat loss of A to that of B is ( 2^{4 / 3} ) B. The ratio of heat loss of A to that of B is ( 2^{2 / 3} ) C. The ratio of the initial rate of cooling of A to that of B is ( 2^{2 / 3} ) D. The ratio of the initial rate of cooling of ( A ) to that of ( B ) is ( 2^{-1 / 3} ) |
12 |

1104 | In the given figure, electric lines of force diagram is shown. Then: A ( cdot E_{A}E_{B}>E_{C} ) ( mathbf{c} cdot E_{C}>E_{B} ) ( mathbf{D} cdot E_{A}=E_{B}=E_{C} ) |
12 |

1105 | Two identical copper spheres carrying chatges ( +Q ) and ( -9 Q ) separated by a certain distance has attractive force ( F ) If the spheres are allowed to touch eacxh other and moved to distance of separation ‘x’. So that the force between them becomes ( frac{4 F}{9} . ) Then ( x ) is equal to ( A cdot d ) B. 2d ( c cdot d / 2 ) D. 4d |
12 |

1106 | Four charges are placed at the circumference of dial clock as shown in figure. If the clock has only hour hand, then the resultant force on a positive charge ( q_{0} ) placed at the centre, points in the direction which show the time as: ( mathbf{A} cdot 1: 30 ) B. 7: 30 ( c cdot 4: 30 ) D. 10: 30 |
12 |

1107 | When a comb rubbed with dry hair attracts pieces of paper. This is because the A. comb polarizes the piece of paper B. comb induces a net dipole moment opposite to the direction of field c. electric field due to the comb is uniform D. comb induces a net dipole moment perpendicular to the direction of field E. paper acquires a net charge |
12 |

1108 | During discharging of a charged glass rod via earthing, the connecting material can be A. another glass rod B. a conducting wire ( c . ) fur D. an ebonite rod |
12 |

1109 | A charge ( Q ) is uniformly distributed over the surface of two concentric conducting spheres of radii ( R ) and ( r ) ( (R>r) ) such that surface charge densities are same for both spheres. Then potential at the common center of these spheres is A ( cdot frac{k Q(R+r)}{R r} ) B. ( frac{k Q(R+r)}{left(R^{2}+r^{2}right)} ) c. ( frac{k Q}{sqrt{R^{2}+r^{2}}} ) D ( quad k Qleft(frac{1}{R}-frac{1}{r}right) ) |
12 |

1110 | Identify incorrect for electric charge ( boldsymbol{q} ) A. Quantised B. Conserved C. Additive D. Non-transferable |
12 |

1111 | Electric flux is a A. scalar B. vector c. constant D. independent |
12 |

1112 | Intensity of an electric field (E) depends on distance ( r . ) In case of dipole, it is related as: ( ^{mathrm{A}}=_{E} propto frac{1}{r} ) в. ( quad E propto frac{1}{r^{2}} ) c. ( quad E propto frac{1}{r^{3}} ) D. ( quad E propto frac{1}{r^{4}} ) |
12 |

1113 | The gravitational force is A. always attractive B. always repulsive C. either attractive or repulsive D. None of these |
12 |

1114 | A metal sphere is kept on an insulating stand. A negatively charged rod is brought near it, then the sphere is earthed as shown. On removing the earthing, and taking the negatively charged rod away, what will be the nature of charge on the sphere? Give reason for your answer. Ground |
12 |

1115 | A radio active nucleus (initial mass number A and atomic number Z emits 4 ( alpha ) – particles and 3 positrons).The ratio of numbers of neutrons to that of protons in the final nucleus will be A ( cdot frac{A-Z-4}{Z-8} ) B. ( frac{A-Z-3}{Z-2} ) c. ( frac{A-Z-2}{Z-3} ) D. ( frac{A-Z-5}{Z-11} ) |
12 |

1116 | Figure shows some of the electric field lines corresponding to an electric field. The figure suggests that: A ( cdot E_{A}>E_{B}>E_{C} ) B . ( E_{A}=E_{B}=E_{O} ) ( mathbf{c} cdot E_{A}=E_{C}>E_{B} ) D. ( E_{A}=E_{C}<E_{B} ) |
12 |

1117 | Three charges ( -q_{1},+q_{2} ) and ( -q_{3} ) are placed as shown in the figure. The ( x ) -component of the force on ( -q_{1} ) is proportional to: A ( cdot frac{q_{2}}{b^{2}}-frac{q_{3}}{a^{2}} cos theta ) B ( cdot frac{q_{2}}{b^{2}}+frac{q_{3}}{a^{2}} sin theta ) C ( cdot frac{q_{2}}{b^{2}}+frac{q_{3}}{a^{2}} cos theta ) D. ( frac{q_{2}}{b^{2}}-frac{q_{3}}{a^{2}} sin theta ) |
12 |

1118 | A neutral rubber rod and a neutral piece of fur have equal amounts of negative and positive charge. When the fur is rubbed against the rod, a transfer of electrons occurs. The transfer of electrons and mass transfer respectively takes place from A. fur to rubber rod; rubber rod to fur B. fur to rubber rod; fur to rubber rod c. rubber rod to fur; rubber rod to fur D. rubber rod to fur; fur to rubber rod |
12 |

1119 | Assertion At a point in space, the electric field points towards north. In the region, surrounding this point the rate of change of potential will be zero along the east and west Reason Electric field due to a charge is in the space around the charge A. Both Assertion and Reason are correct and Reason is the correct explanation for Assertion B. Both Assertion and Reason are correct but Reason is not the correct explanation for Assertion C. Assertion is correct but Reason is incorrect D. Assertion is incorrect but Reason is correct |
12 |

1120 | Sparking occurs when a load is switched off because the circuit has high : A . resistance B. inductance c. capacitance D. impedance |
12 |

1121 | Mass of negative ion is slightly greater than its neutral atom. A. True B. False |
12 |

1122 | State Coulomb’s law. | 12 |

1123 | What is the work done in rotating the dipole through ( 180^{circ} ? ) A ( cdot frac{partial q Q x}{pi varepsilon_{0}left(R^{2}+x^{2}right)^{3 / 2}} ) В. ( frac{partial q Q x}{2 pi varepsilon_{0}left(R^{2}+x^{2}right)^{3 / 2}} ) c. ( frac{2 partial q Q x}{pi varepsilon_{0}left(R^{2}+x^{2}right)^{3 / 2}} ) D. ( frac{partial q Q x}{3 pi varepsilon_{0}left(R^{2}+x^{2}right)^{3 / 2}} ) |
12 |

1124 | Two small objects each with a net charge of ( +Q ) exert a force of magnitude Fon each other. We replace one of the objects with another whose net charge is ( +4 Q . ) We move the ( +Q ) and ( +4 Q ) charges to be 3 times as far apart as they were. What is the magnitude of the force on the ( +4 Q ) charge? ( A cdot F ) B. 4F ( c cdot 4 F / 3 ) D. 4F/9 E. F/3 |
12 |

1125 | The electric field in a region of space is given by ( boldsymbol{E}=mathbf{5} boldsymbol{i}+mathbf{2} boldsymbol{j} boldsymbol{N} / boldsymbol{C} . ) Determine the electric flux due to this field through an area ( 2 m^{2} ) lying in the ( Y Z ) plane: A . 10 B . 20 c. ( 10 sqrt{2} ) ( D. ( 2 sqrt{29} ) |
12 |

1126 | A charges of ( 8.7 times 10^{-18} C ) A. Does exist B. Does not exist c. Exists for a short time D. Exists only if placed in higher orbits |
12 |

1127 | Electric charge is measured in A . coulombs B. amperes c. volts D. watts |
12 |

1128 | A large sheet carries uniform surface charge density ( sigma . ) A rod length ( 2 l ) has a linear charge density ( lambda ) on one half and ( -lambda ) on the second half. The rod is hinged at the midpoint 0 and makes and angle ( theta ) with the normal to the sheet. The torque experienced by the rod is: ( A cdot O ) B. ( frac{sigma lambda l^{2}}{2 varepsilon_{0}} sin theta ) ( ^{text {c. }} frac{sigma lambda l^{2}}{varepsilon_{0}} sin theta ) D. ( frac{sigma lambda l}{2 varepsilon_{0}} ) |
12 |

1129 | Consider the motion of a positive point charge in a region where there are simultaneous uniform electric and magnetic fields ( mathrm{E}=mathrm{EO} mathrm{j} ) and ( mathrm{B}=mathrm{BO} mathrm{j}, mathrm{At} ) time ( t=0, ) this charge has velocity ( v ) in the ( x ) -y plane, making an angle 0 with the ( x ) -axis. Which of the following option(s) is(are) correct for time ( t>0 ? ) |
12 |

1130 | A charged particle q of mass m is in equilibrium at a height h from a horizontal infinite line charge with uniform linear charge density ( lambda ). The charge lies in the vertical plane containing the line charge. If the particle is displaced slightly (vertically), prove that the motion of the charged particle will be simple harmonic. Also find its time period |
12 |

1131 | A straight segment ( O C ) (of length ( L ) ) of a circuit carrying a current ( I ) is placed along the ( x ) -axis. Two infinitely long straight wires ( A ) and ( B ), each extending from ( z=-infty ) to ( +infty, ) are fixed at ( y= ) ( -a ) and ( y=+a ) respectively, as shown in the figure. If the wires ( A ) and ( B ) each carry a current ( I ) into the plane of the paper, obtain the expression for the force acting ont he segment ( O C . ) What will be the force on ( O C ) if the current in the wire ( B ) is reversed? |
12 |

1132 | A charge ( q_{0} ) is brought from infinity to the centre of dipole. Find work done? в. ( 0 . ) ( c cdot 3 J ) D. ( 4 J ) |
12 |

1133 | A and B are two points on the axis and the perpendicular bisector, respectively of an electric dipole. A and B are far away from the dipole and at equal distances from it. The fields at ( A ) and ( B ) ( operatorname{are} vec{E}_{A} ) and ( vec{E}_{B} . ) Then: ( mathbf{A} cdot vec{E}_{A}=vec{E}_{B} ) B ( cdot vec{E}_{A}=2 vec{E}_{B} ) ( mathbf{c} cdot vec{E}_{A}=-2 vec{E}_{B} ) D ( cdotleft|vec{E}_{B}right|=frac{1}{2}left|vec{E}_{A}right| ), and ( left|vec{E}_{A}right| ) is perpendicular to ( vec{E}_{B} ) |
12 |

1134 | Which of the following is best insulator? A. Carbon B. Paper c. Graphite D. Ebonite |
12 |

1135 | How many electronic charges from 1 coulomb? A. ( 9.1 times 10^{-31} ) B . ( 1.6 times 10^{18} ) c. ( 62.5 times 10^{17} ) D. ( 1.76 times 10^{11} ) |
12 |

1136 | Identify the correct statement: ( A ). ( A ) and ( B ) will have the same mass afterwards. B. A will have more mass than B afterwards. C. A will have lesser mass than B afterwards. D. None of these |
12 |

1137 | A solid sphere of radius ( R ) has a charge ( +2 Q . ) A hollow spherical shell of radius ( 3 R ) placed concentric with the first sphere has net charge – ( Q ). Calculate the potential difference between the spheres: ( ^{A} cdot frac{Q}{3 pi varepsilon_{0} R} ) в. ( frac{2 Q}{3 pi varepsilon_{Omega} R} ) c. ( frac{3 Q}{pi varepsilon_{0} R} ) ( D ) |
12 |

1138 | Two fixed point charges ( +4 e ) and ( +e ) are separated by a distance a. Where should the third point charge be placed from ( +4 e ) charge for it to be in equilibrium? A ( cdot frac{2}{3} a ) в. ( frac{4}{3} a ) ( c cdot frac{1}{3} a ) D. None of these |
12 |

1139 | Explain why a charged balloon is repelled by another charged balloon whereas an uncharged balloon is attracted by another charged balloon? |
12 |

1140 | An electric dipole kept in a uniform electric field experiences: A. Force and a torque B. A force, but no torque c. A torque but no force D. Neither a force nor a torque |
12 |

1141 | Four identical charges of charge ( q ) are placed at the corners of a square of sides r as shown above. Find the magnitude of the net force acting on a charge of magnitude ( 2 q ) placed in the center of the square. ( mathbf{A} cdot mathbf{0} ) ( mathbf{B} cdot frac{2 k q^{2}}{r^{2}} ) ( mathbf{c} cdot frac{4 k q^{2}}{r^{2}} ) D. ( frac{16 k q^{2}}{r^{2}} ) E ( cdot frac{text { g } 2 k q^{2}}{r^{2}} ) |
12 |

1142 | A charge ( Q ) is distributed uniformly in a sphere (solid). Then the electric field at any point r where ( r<R ) (R is radius of the sphere) varies as A ( cdot r^{1 / 2} ) B ( cdot r^{-1} ) ( c ) D. ( r^{-2} ) |
12 |

1143 | Assertion A charge ( q ) is placed inside the square of side b. The flux associated with the square is independent of side length. Reason Gauss’s law is independent of size of |
12 |

1144 | The equi-potential surface for an electric dipole is: A. the dipole axis B. the perpendicular bisector of the dipole axis C. a line parallel to the dipole axis D. a line passing through one of the charges |
12 |

1145 | Four electric charges are arranged as shown in the figure at the four corners of a square of side a. The potential energy of the system is: A. Zero B. Negative c. Positive D. Greater than ( frac{1}{4 pi varepsilon} frac{2 q^{2}}{a} ) |
12 |

1146 | A charged particle of mass ( 5 times 10^{-6} k g ) is held stationary in space by placing it in an electric field of strength ( 10^{6} N C^{-1} ) directed vertically downwards. The charge on the particle is ( left(boldsymbol{g}=mathbf{1 0 m} boldsymbol{s}^{-2}right) ) A. ( -20 times 10^{-5} mu C ) B. ( -5 times 10^{-5} mu C ) c. ( 5 times 10^{-5} mu C ) D. ( 20 times 10^{-5} mu C ) |
12 |

1147 | For ( a=0, ) the value of ( d( ) maximum value of ( rho ) as shown in the figure) is ( ^{A} cdot frac{3 Z e}{4 pi R^{3}} ) в. ( frac{3 Z}{pi R^{3}} ) c. ( frac{4 Z e}{3 pi R^{3}} ) D. ( frac{Z e}{3 pi R^{3}} ) |
12 |

1148 | Two concentric spheres of radii R and 2R are charged. The inner sphere has a charge of ( 1 mu mathrm{C} ) and the outer sphere has a charge of ( 2 mu mathrm{C} ) of the same sign: The potential is ( 9000 mathrm{V} ) at a distance ( 3 mathrm{R} ) from the common centre. The value of ( mathrm{R} ) is : ( A cdot 1 m ) B. 2 ( m ) ( c cdot 3 m ) D. ( 4 mathrm{m} ) |
12 |

1149 | Two conducting concentric, hollow spheres ( A ) and ( B ) have radii a and ( b ) respectively, with A inside B.Their common potentials is ( V ). A is now given some charge such that its potential becomes zero. The potential of B will now be : A. 0 B. ( V(1-a / b) ) c. ( v ) a/b D. v b/a |
12 |

1150 | State True or False : Human body is a good conductor of electricity. A. True B. False |
12 |

1151 | Assertion Gauss theorem can be applied only for a closed surface. Reason Electric flux can be obtained passing from an open surface also. A. Both Assertion and Reason are correct and Reason is the correct explanation for Assertion B. Both Assertion and Reason are correct but Reason is not the correct explanation for Assertion C. Assertion is correct but Reason is incorrect D. Both Assertion and Reason are incorrect |
12 |

1152 | Three concentric conducting spherical shells of radii ( boldsymbol{R}, 2 boldsymbol{R} ) and ( boldsymbol{3} boldsymbol{R} ) carry charges ( Q,-2 Q ) and ( 3 Q, ) respectively Find the electric potential at ( r=R ) and ( boldsymbol{r}=boldsymbol{3} boldsymbol{R}, ) where ( boldsymbol{r} ) is the radial distance from the centre ( ^{mathrm{A}} cdot frac{Q}{6 pi varepsilon_{0} R}, frac{Q}{4 pi varepsilon_{0} R} ) в. ( frac{Q}{4 pi varepsilon_{0} R}, frac{Q}{6 pi varepsilon_{0} R} ) c. ( frac{Q}{2 pi varepsilon_{0} R}, frac{Q}{3 pi varepsilon_{0} R} ) D. ( frac{Q}{3 pi varepsilon_{0} R}, frac{Q}{2 pi varepsilon_{0} R} ) |
12 |

1153 | ( y= ) ( x ) 0 |
12 |

1154 | Observe the circit in the figure. Which of the following materials can be used to complete the open fruit and light the bloub [Paper, rubber bandm, steel spon silk, plastic, nail, blade] |
12 |

1155 | The electric field at ( r=R ) is: A. independent of a B. directly proportional to a C. directly proportional to ( a^{2} ) D. inversely proportional to |
12 |

1156 | Between two plates charged to ( 10 q ) there is an electric field ( E, ) what acceleration will a positively charged particle, with a charge of ( q ) and a mass of ( m ) experience in this region, due only the electric field? ( ^{text {A } cdot frac{21 q E}{m}} ) в. ( frac{11 q E}{m} ) ( ^{mathbf{c}} cdot frac{10 q E}{m} ) D. ( frac{q E}{m} ) |
12 |

1157 | Find the electric flux through each of the six cube faces ( S_{1}, S_{2}, S_{3}, S_{4}, S_{5} ) and ( boldsymbol{S}_{6} ) |
12 |

1158 | Six charges are kept at the vertices of a regular hexagon as shown in the figure. f magnitude of force applied by ( +Q ) on ( +q ) charge is ( F ), then net electric force on the ( +Q ) is ( n F ). Find the value of ( n ) |
12 |

1159 | Rub a glass rod with a piece of silk. What happens? A. the glass has a slightly positive charge and the silk is also slightly positive B. the glass has a slightly positive charge and the silk is slightly negative C. the glass has a slightly negative charge and the silk is also slightly negative D. the glass has a slightly negative charge and the silk is slightly positive |
12 |

1160 | A conductive base is provided to the gold-leaf electroscope so that A. the leaves discharge before tearing if an excess charge is applied. B. the leaves discharge before tearing if negative charge is applied. c. the leaves discharge before tearing if positive charge is applied. D. All of the above |
12 |

1161 | State whether true or false: Unlike charges attract each other A. True B. False |
12 |

1162 | Match the terms in column I with those of column II ( begin{array}{ll}text { Column – I } & text { Column – II } \ text { i. Electric fuse } & text { A. Chemical effect } \ text { ii. Relay } & text { B. Electric discharge } \ text { iii. CFL } & text { C. Magnetic effect } \ text { iv. Button cell } & text { D. Heating effect }end{array} ) iii-A, iv-D ( A cdot ) i-C, ii-B, B. i-B, ii-A, iii-C, iv-D c. i-D, ii-C, iii-B, iv-A D. i-D, ii-B, iii-C, iv-D |
12 |

1163 | Electric field at point (30,30,0) due to a point charge of ( 8 times 10^{-3} mu C ) placed at origin will be (coordinates are in ( mathrm{cm} ) ) A. ( 8000 N / C ) в. ( 4000(hat{i}+hat{j}) N / C ) c. ( 200 sqrt{2}(hat{i}+hat{j}) N / C ) D. ( 400 sqrt{2}(hat{i}+hat{j}) N / C ) |
12 |

1164 | A charge ( Q ) is enclosed by a Gaussian spherical surface of radius R. If the radius is doubled, then the outward electric flux will : A. be doubled B. increase four times c. be reduced to half D. remain the same |
12 |

1165 | Two thin infinite parallel sheets have uniform surface densities of charge ( +boldsymbol{sigma} ) and ( -sigma . ) Electric field in the space between the two sheets is: A ( cdot sigma / epsilon_{0} ) в. ( sigma / 2 epsilon_{0} ) ( mathbf{c} cdot 2 sigma / epsilon_{0} ) D. zero |
12 |

1166 | A comb run through ones hair attracts small bits of paper. What happens, if the hair are wet or if it is a rainy day? A. The comb does not get charged and it will not attract small bits of paper B. The comb does not get charged but it will attract small bits of paper. C. The comb does gets charged and it will attract small bits of paper. D. The comb does gets charged but it will not attract small bits of paper. |
12 |

1167 | A cube of side ( 20 mathrm{cm} ) is kept in a region as shown in the figure. An electric field ( vec{E} ) exists in the region such that the potential at a point is given by ( boldsymbol{V}= ) ( 10 x+5, ) where ( V ) is in volt and ( x ) is in ( m ) Find the electric flux through the cube |
12 |

1168 | What will be the electric flux through the sphere ( S_{1} ) if a medium of dielectric constant ( epsilon_{r} ) is introduced in the space inside ( S_{1} ) in place of air A. ( frac{20}{epsilon epsilon_{n}} ) в. ( frac{40}{epsilon_{0} epsilon_{r}} ) c. ( frac{20 epsilon_{c}}{epsilon_{0}} ) D. ( frac{406}{6} ) |
12 |

1169 | For an ideal conductor thermal resistance is : A. unity B. infinity c. zero D. 1000 |
12 |

1170 | A charge particle of mass ‘m’ & charge q is released from rest from a given position ( Q ) inside a fixed vertical semicircular trough. For the presence and the absence of magnetic field normal reaction acting on the change at Pare ( N_{1} ) and ( N_{2} ) respectively. Neglecting friction and assuming gravity presence. The value of ( N_{1}-N_{2} ) is: A ( .2 B q sqrt{2 g R} ) в. ( frac{B q sqrt{2 g R}}{2} ) с. ( B q sqrt{2 g R} ) D. ( frac{B q sqrt{2 g R}}{4} ) |
12 |

1171 | ( operatorname{Let} rho(r)=frac{Q r}{4 pi R^{4}} ) be the charge density distribution of a solid sphere of radius ( R ) and total charge ( Q . ) Find the magnitude of electric field at a point ( boldsymbol{P} ) inside the sphere at a distance ( r_{1} ) from the centre of the sphere. A ( cdot frac{Q}{4 pi^{2} epsilon_{6} r_{1}^{2}} ) в. ( frac{Q r_{1}^{2}}{4 pi^{2} epsilon_{epsilon} R^{4}} ) c. ( frac{Q r_{1}^{2}}{16 pi epsilon_{1} R^{4}} ) D. 0 |
12 |

1172 | The total solid angle subtended by the sphere is ( mathbf{A} cdot 0.25 pi ) в. ( 0.5 pi ) c. ( 4 pi ) D . ( 2 pi ) E . ( 1 pi ) |
12 |

1173 | Using Gauss’s law derive an expression for the electric field intensity due to a uniform charged thin spherical shell at a point. (i) Outside the shell (ii) Inside the shell |
12 |

1174 | Two equal positive charges ( Q ) are fixed at points ( (a, 0) ) and ( (-a, 0) ) on the ( x ) axis. An opposite charge ( -q ) at rest is released from point ( (0, a) ) on the ( y ) -axis. The charge ( -boldsymbol{q} ) will A. move to infinity B. Move to origin and rest there c. Undergo SHM about the origin D. Execute oscillatory periodic motion but not SHM |
12 |

1175 | Two isolated metallic solid spheres of radii ( boldsymbol{R} ) and ( 2 boldsymbol{R} ) are charged such that both of these have same charge density ( rho . ) The spheres are located far away from each other, and connected by a thin conducting wire. Then the new charge density on the bigger sphere is: |
12 |

1176 | Two charged objects are brought close to each other. Choose the most appropriate statement from the following options: A. they may attract B. they may repel c. they may attract or repel depending on the type of charges they carry D. there will be no effect |
12 |

1177 | State Gauss theorem and uses it to derive the Coulomb’s inverse square law. |
12 |

1178 | Can a body have a charge of ( 4.8 times 10^{-20} ) coulomb? A. Yes B. No c. мау be D. only semiconductors can have |
12 |

1179 | A charge can exist without mass. A. True B. False |
12 |

1180 | Which of the following represents the electric field lines due to a combination of two negative charges? ( A ) B. ( c ) ( D ) |
12 |

1181 | Let there be a spherically symmetric charge distribution with charge density ( operatorname{varying} operatorname{as} rho(r)=rho_{0}left(frac{5}{4}-frac{r}{R}right) ) upto ( r= ) ( R, ) and ( rho(r)=0 ) for ( r>R, ) where ( r ) is the distance from the origin. Find the electric field at a distance ( r(r<R) ) from the origin. A ( cdot frac{3 rho_{0} r}{4 epsilon_{0}}left(frac{5}{3}-frac{r}{R}right) ) В ( cdot frac{4 rho_{0} r}{3 epsilon_{0}}left(frac{5}{3}-frac{r}{R}right) ) C ( cdot frac{rho_{0} r}{4 epsilon_{0}}left(frac{5}{3}-frac{r}{R}right) ) D. ( frac{3 rho_{0} r}{4 epsilon_{0}}left(frac{5}{4}-frac{r}{R}right) ) |
12 |

1182 | An application of electrostatic induction is This question has multiple correct options |
12 |

1183 | Protons and neutrons inside the nucleus are called |
12 |

1184 | If the electric field to the right of the two sheets is ( K sigma / varepsilon_{0} . ) Find ( mathrm{K} ? ) |
12 |

1185 | Who named positive and negative charges? A. Faraday B. Gauss c. Benjamin Franklin D. Curie |
12 |

1186 | A charge ( q ) is located at the centre of a cube.The electric flux through any face is – ( mathbf{A} cdot frac{2 pi q}{6(4 pi varepsilon)} ) В. ( frac{4 pi q}{6(4 pi varepsilon)} ) ( mathbf{c} cdot frac{pi q}{6(4 pi varepsilon)} ) D. ( frac{q}{6(4 pi varepsilon 0)} ) |
12 |

1187 | Name the physical quantity of which the unit is coulomb: A. capacitance B. charge c. current D. inductance |
12 |

1188 | A circular plane sheet of radius ( 10 mathrm{cm} ) is placed in a uniform electric field of ( mathbf{5} times mathbf{1 0}^{mathbf{5}} mathbf{N} quad mathbf{C}^{-1}, ) making an angle of ( mathbf{6 0}^{mathbf{0}} ) with field. The electric flux through the sheet is ( begin{array}{lll}text { A } cdot 1.36 times 10^{2} N & text { m }^{2} & C^{-1}end{array} ) B . ( 1.36 times 10^{4} N quad m^{2} quad C^{-1} ) ( begin{array}{lll}text { С } cdot 0.515 times 10^{2} N & text { m }^{2} & C^{-1}end{array} ) ( begin{array}{lll}text { D. } 0.515 times 10^{4} N & text { m }^{2} & C^{-1}end{array} ) |
12 |

1189 | A charged particle of mass ( 5 times 10^{-6} mathrm{kg} ) is held stationary in space by placing it in an electric field of strength ( 10^{6} N / C ) directed vertically downwards. The charge on the particle is: ( left(g=10 m / s^{2}right) ) A. ( -20 times 10^{-5} mu C ) B. ( -5 times 10^{-5} mu C ) c. ( 5 times 10^{-5} mu C ) D. ( 20 times 10^{-5} mu C ) |
12 |

1190 | A metal sphere A of radius ( r_{1} ) charged to a potential ( phi_{1} ) is enveloped by a thin walled conducting spherical shell B of radius ( r_{2} ). Then potential ( phi_{2} ) of the sphere ( A ) after it is connected to the shell B by a thin conducting wire will be A ( cdot phi_{1} frac{r_{1}}{r_{2}} ) В ( cdot phi_{1}left(frac{r_{2}}{r_{1}}right) ) c. ( phi_{1}left(1-frac{r_{2}}{r_{1}}right) ) ( mathbf{D} cdot mathbf{q} phi_{1}left(frac{r_{1} r_{2}}{r_{1} r_{2}}right) ) |
12 |

1191 | A small ball of mass ( m ) and charge ( +q ) tied with a string of length ( l ) is rotating in a vertical circle under gravity and a uniform horizontal electric field ( boldsymbol{E} ) as shown. The tension in the string will be minimum for: A ( cdot quad theta=tan ^{-1}left(frac{q E}{m g}right) ) B . ( theta=pi ) ( ^{mathbf{c}} cdot_{theta}=pi-tan ^{-1}left(frac{q E}{m g}right) ) D. |
12 |

1192 | Above an infinitely large plane carrying charge density ( sigma, ) the electric field points up and is equal to ( frac{sigma}{2 epsilon_{0}} . ) What is the magnitude and direction of the electric field below the plane? ( A cdot sigma / 2 epsilon_{0}, ) down В ( cdot sigma / 2 epsilon_{0}, ) up ( mathrm{c} cdot sigma / epsilon_{0}, ) down D. ( sigma / epsilon_{0}, ) up |
12 |

1193 | Which of the following may be discontinuous across a charged conducting surface? A. Electric potential B. Electric intensity c. Both electric intensity and potential D. None of these |
12 |

1194 | In the diagram shown, a positively charged rod is brought near the knob of an uncharged electroscope. The leaves will : A. diverge and will be negatively chargedd B. diverge and will be positively charged C. converge and will be negatively chargedd D. converge and will be positive chargedd E. converge and will remain neutral |
12 |

1195 | Which is the elementary quantum of energy? A. Photon B. Electron c. Proton D. Neutron |
12 |

1196 | The electric field in a region is radially outward with magnitude ( boldsymbol{E}=boldsymbol{alpha} boldsymbol{r} ) Calculate the charge contained in a sphere of radius ( R ) centered at the origin. Calculate the value of the charge if ( alpha=100 V m^{-2} ) and ( R=0.30 mathrm{m} ) A ( cdot 3 times 10^{-7} C ) В. ( 12 times 10^{-10} mathrm{C} ) c. ( 3 times 10^{-10} C ) D. ( 7 times 10^{-10} C ) |
12 |

1197 | Figure shows two large cylindrical shells having uniform linear charge densities ( +a lambda ) and ( -lambda . ) Radius of inner cylinder as ‘a’ and that o outer cylinder is ‘b’. A charged particle of mass m, charge q revolves in a circle of radius r.Then its speed ‘v’ is : (Neglect gravity and assume the radii of both the cylinders to be very small in comparision to their length) A ( cdot sqrt{frac{lambda q}{2 pi epsilon_{0} m}} ) B. ( sqrt{frac{2 lambda q}{pi epsilon_{0} m}} ) c. ( sqrt{frac{lambda q}{pi epsilon_{0} m}} ) D. ( sqrt{frac{lambda q}{4 pi epsilon_{0} m}} ) |
12 |

1198 | Assertion Insulators do not allow flow of current through them. Reason Insulators have no free charge carriers. A. Both Assertion and Reason are correct and Reason is the correct explanation for Assertion B. Both Assertion and Reason are correct but Reason is not the correct explanation for Assertion C. Assertion is correct but Reason is incorrect D. Both Assertion and Reason are incorrect |
12 |

1199 | What is the mangitude of a point charge chosen so that electric field 50 ( mathrm{cm} ) away has magnitude ( 2.0 mathrm{N} / mathrm{C} ) ? |
12 |

1200 | An infinite line charge is at the axis of a cylinder of length ( 1 mathrm{m} ) and radius ( 7 mathrm{cm} ) If electric field at any point on the curved surface of cylinder is ( 250 N C^{-1} ) then net electric flux through the cylinder is: |
12 |

1201 | Three point charges ( q ) are placed at three vertices of an equilateral triangle of side a. The magnitude of electric force on any charge due to the other two is equal to ( frac{sqrt{x}}{4 pi varepsilon_{0}}left(frac{q}{a}right)^{2} ) where ( x ) is: | 12 |

1202 | If the surface normal vector ( hat{n} ) makes an angle ( theta ) with the electric field ( vec{E} ), then the electric flux through a surface of ( operatorname{area} d S ) is given by A. ( phi=E d S sin theta ) ( mathbf{B} cdot phi=E d S cos theta ) c. ( phi=d S cos theta ) D. ( phi=E cos theta ) |
12 |

1203 | The Sl unit of charge is….. A. ohm B. volt ( c . ) farad D. coulomb |
12 |

1204 | Assertion On going away from a point charge or a small electric dipole, electric field decreases at the same rate in both the cases. Reason Electric field is inversely proportional to square of distance from the charge or on electric dipole. A. Both Assertion and Reason are correct and Reason is the correct explanation for Assertion. B. Both Assertion and Reason are correct but Reason is not the correct explanation for Assertion C. Assertion is correct but Reason is incorrect. D. Both Assertion and Reason are incorrect. |
12 |

1205 | The tangent drawn on electric field lines at a point gives the direction of lines of force at that point. A. True B. False |
12 |

1206 | A positive charge ( +mathrm{Q} ) is located at ( 5 mathrm{cm} ) on the positive y-axis. A negative charge -Q is located at ( 5 mathrm{cm} ) on the positive ( x ) – axis. A positive test charge is at the origin where it feels a force “F” from the positive charge above it. What is the net force from both charges? ( mathbf{A} cdot 2 F ) B ( . F^{2} ) ( c cdot frac{F}{2} ) D. ( sqrt{2} F ) |
12 |

1207 | Some materials have electrons that are tightly bound to the nucleus and are not free to travel within the substance. These materials are called A. conductors B. insulators c. semiconductors D. none of these |
12 |

1208 | The electric field at point Pjust outside the outer surface of a hollow spherical conductor of inner radius ( 10 mathrm{cm} ) and outer radius ( 20 mathrm{cm} ) has magnitude 450 ( mathrm{N} / mathrm{C} ) and is directed outward. When an unknown point charge ( Q ) is placed at the center of the sphere, the electric field at point ( P ) is still pointing outward but is now ( 180 mathrm{N} / mathrm{C} ). What is the value of charge Q? A . 4.5 nc в. 1.5 nc ( c .-1.5 mathrm{nc} ) D. -1.2 nc |
12 |

1209 | Two charges of magnitudes ( -2 Q ) and ( +Q ) are located at points ( (a, 0) ) and ( (4 a, 0) ) respectively. What is the electric flux due to these charges through a sphere of radius ( ^{prime} 3 a^{prime} ) with its centre at the origin? |
12 |

1210 | Using general logic for electric field, the flux of ( vec{g} ) through any closed surface is given by : A ( cdot oint vec{g} cdot d vec{s}=4 pi G m_{text {endosed }} ) в. ( oint vec{g} cdot d vec{s}=-4 pi G m_{text {endosed }} ) c. ( oint vec{g} cdot d vec{s}=G m_{text {enclosed}} ) D ( cdot oint vec{g} cdot d vec{s}=-G m_{text {endose}} ) |
12 |

1211 | A ball with charge -50e is placed at the centre of a hollow spherical shell has a net charge of -50e. What is the charge on the shell’s outer surface? A . – -50e B. zero ( c cdot-100 e ) D. ( +100 e ) |
12 |

1212 | An electron of mass ( m_{e}, ) initially at rest, move through a certain distance in a uniform electric field in time ( t_{1} . A ) proton of mass ( m_{p}, ) also, initially at rest takes time ( t_{2} ) to move through an equal distance in this uniform electric field. Neglecting the effect of gravity, the ratio ( t_{2} / t_{1} ) is nearly equal to A. 1 в. ( _{left(m_{p} / m_{e}right)^{1 / 2}} ) ( ^{mathbf{c}} cdotleft(m_{e} / m_{p}right)^{1 / 2} ) D. 1836 |
12 |

1213 | If the distance between two unlike poles is doubled then the force of attraction between them becomes ( _{–}-_{-}- ) times its original value A . 0.25 B. 0.5 c. 0.125 D. 2 |
12 |

1214 | A charge 10 esu is placed at a distance of ( 2 mathrm{cm} ) from a charge 40 esu and ( 4 mathrm{cm} ) from another charge of 20 esu. The potential energy 10 esu in ergs is A. 87.5 в. 112.5 ( c cdot 150 ) D. 250 |
12 |

1215 | Two free charges ( +q ) and ( +4 q ) are placed at a distance ( ^{prime} r^{prime} ) between them. A third charge is placed in between them and find the third charge when the system is in equilibrium. A ( cdot frac{4 q}{3} ) в. ( frac{4 q}{9} ) c. ( frac{2 q}{9} ) D. ( frac{q}{9} ) |
12 |

1216 | The cube as shown in Fig. has sides of length ( boldsymbol{L}=mathbf{1 0 . 0} mathrm{cm} . ) The electric field is uniform, has a magnitude ( boldsymbol{E}=mathbf{4 . 0 0} times ) ( 10^{3} N C^{-1}, ) and is parallel to the ( x y- ) plane at an angle of ( 37^{circ} ) measured from the ( +x-a x i s ) towards the ( +y-a x i s ) The surfaces that have zero flux are ( A cdot S_{1} ) and ( S_{3} ) B. ( S_{5} ) and ( S_{6} ) ( c cdot S_{2} ) and ( S_{4} ) D. ( S_{1} ) and ( S_{1} ) |
12 |

1217 | Using Gauss’s theorem determine the electric field due to a uniformly charged sphere shell at a point which is | 12 |

1218 | An electron of mass ( M_{e}, ) initially at rest moves through a certain distance in a uniform electric field in time ( t_{1} . A ) proton of mass ( M_{p}, ) also initially at rest, takes time ( t_{2}, ) to move through an equal distance in this uniform electric field. Neglecting the effect of gravity, the ratio ( t_{2} / t_{1} ) is nearly equal to? A . 1 в. ( sqrt{frac{M_{p}}{M_{e}}} ) c. ( sqrt{frac{M_{e}}{M_{p}}} ) D. 1836 |
12 |

1219 | In a region of space the electronic field is given by ( vec{E}=(8 hat{i}+4 hat{j}) N / C . ) The electric flux through a surface of area ( 10 mathrm{m}^{2} ) in the x-y plane is A. 80 units B. 40 units c. 120 units D. zero |
12 |

1220 | Two pith balls carrying equal charges are suspended from a common point by strings of equal length, the equilibrium separation between them is r. Now the strings are rigidly clamped at half the height. The equilibrium separation between the balls now become: ( A ) B. ( left(frac{r}{3 sqrt{2}}right) ) c. ( left(frac{2 r}{sqrt{3}}right) ) D. ( frac{2 r}{3} ) |
12 |

1221 | Assume that a neutron breaks into a proton and an electron. The energy released during this process is : (mass of neutron ( =1.6725 times 10^{-27} k g, ) mass of proton ( =1.6725 times 10^{-27} k g, ) mass of electron ( left.=9 times 10^{-31} k gright) ) ( mathbf{A} .5 .4 mathrm{MeV} ) в. ( 0.73 mathrm{MeV} ) c. ( 7.10 M e V ) D. ( 6.30 mathrm{MeV} ) |
12 |

1222 | An electric dipole will experience a net force when it is placed in : A. Uniform electric field B. A non-uniform electric field c. Both the above cases D. None of these |
12 |

1223 | In electrical field, equipotential surfaces must: A. be plane surfaces B. be tangential to the direction of field C. be spaced such that surfaces having equal difference in potential are separated by equal distance D. have decreasing potential in the direction of field |
12 |

1224 | A point charge of ( +6 mu C ) is placed at a distance ( 20 mathrm{cm} ) directly above the centre of a square of side ( 40 mathrm{cm} . ) The magnitude of the flux through the square is ( A cdot epsilon_{0} ) в. ( frac{1}{epsilon_{0}} ) c. ( epsilon_{0} times 10^{-6} ) D. ( frac{1}{epsilon_{0}} times 10^{-6} ) |
12 |

1225 | An electric dipole has the magnitude of its charge as ( q ) and its dipole moment is ( boldsymbol{p} . ) It is placed in uniform electric field ( boldsymbol{E} ) If its dipole moment is along the direction of the field, the force on it and its potential energy are respectively A. ( q . E ) and max в. 2q.E and min c. ( q . E ) and min D. zero and min |
12 |

1226 | An electric dipole of dipole moment ( 20 times 10^{-6} C ) is enclosed by closed surface. What is the net electric flux coming out of this surface? |
12 |

1227 | At what separation should two equal charges, ( 1.0 C ) each, be placed so that the force between them equals the weight of a ( 50 k g ) person? |
12 |

1228 | The electric field just outside the surface of conductor of area ( boldsymbol{A} ) and surface charge density ( sigma ) is given by A ( cdot frac{sigma}{3 epsilon_{0}} ) в. ( frac{sigma}{2 epsilon_{0}} ) c. ( frac{sigma}{epsilon_{0}} ) D. ( frac{2 sigma}{epsilon_{0}} ) |
12 |

1229 | Three charged particles are in equilibrium under their electrostatic forces only. Then A. The particles must be collinear B. All the charges cannot have the same magnitude c. All the charges cannot have the same sign D. The equilibrium is unstable E. All option is correct |
12 |

1230 | Charging by friction is accompanied by loss or gain of electrons. State which body loses electrons when an ebonite rod is rubbed with fur. A . ebonite B. fur c. hand D. Both fur and ebonite |
12 |

1231 | The charge on an electron is: A . ( 1 mathrm{c} ) B ( cdot+1.6 times 10^{-19} mathrm{C} ) ( mathrm{c} ldots 1.6 times 10^{-19} mathrm{C} ) D. 6.25 ( times 10^{18} mathrm{C} ) |
12 |

1232 | Why do electric lines of force never intersect each other? |
12 |

1233 | In a region of uniform electric field of intensity ( boldsymbol{E}, ) an electron of mass ( boldsymbol{m}_{e} ) is relased from rest. The distance travelled by the electron in a time ( t ) is: ( ^{mathbf{A}} cdot frac{2 m_{e} t^{2}}{e} ) B. ( frac{e E t^{2}}{2 m_{e}} ) ( ^{mathbf{c}} cdot frac{m_{e} g t^{2}}{e E} ) D. ( frac{2 E t^{2}}{e m_{c}} ) |
12 |

1234 | Does the charge given to a metallic sphere depends on whether it is hollow or solid? Given reason for your answer. | 12 |

1235 | The electric field in a region is radially outward with magnitude ( mathrm{E}=2 mathrm{r} . ) The charge contained in a sphere of radius a ( =2 mathrm{m} ) centred at the origin is ( 4 x pi epsilon_{0} . ) Find the value of ( x ) |
12 |

1236 | Symbol for steradian is | 12 |

1237 | Two identical metallic spheres ( A ) and ( B ) of exactly equal masses are taken. Sphere ( A ) is given positive charge ( Q ) columb and B is given an equal negative charge. So initially before the charge is given. What will be the masses after the charging? |
12 |

1238 | If a point lies at a distance ( ^{prime} x^{prime} ) from the mid point of the dipole along its axis, the electric potential at this point is proportional to : A ( cdot frac{1}{x^{2}} ) B. ( frac{1}{x^{3}} ) c. ( frac{1}{x^{4}} ) D. ( frac{1}{x^{3 / 2}} ) |
12 |

1239 | Which of the following figure represents the electric field lines due to the combination of one positive and one negative charge? ( A ) в. ( c ) D. |
12 |

1240 | Four charges are kept at the corners of a square ( A B C D ) as shown. The force on a positive charge placed at the centre of the square is ( A ) B. Along diagonal ACC c. Along diagonal BD D. perpendicular to side AB |
12 |

1241 | ( A ) and ( B ) are two points on the axis and the perpendicular bisector respectively of an electric dipole. A and B are far away from the dipole and at equal distances from it. The potentials at ( A ) and ( mathrm{B} ) are ( V_{A} ) and ( V_{B} ) respectively. Then A. ( V_{A}=V_{B}=0 ) в. ( V_{A}=2 V_{B} ) ( mathbf{c} cdot V_{A} neq 0, V_{B}=0 ) D. ( V_{A} neq 0, V_{B} neq 0 ) |
12 |

1242 | Electric charge is due to the loss or gain of A. protons B. neutrons c. electrons D. none of these |
12 |

1243 | The field potential inside a charged ball of radius ( mathrm{R} ) and centre at o depends only on distance from its center as ( V(r)= ) ( boldsymbol{alpha} boldsymbol{r}^{2}+boldsymbol{beta} ) when ( boldsymbol{alpha}, boldsymbol{beta} ) are ( + ) ve constant now choose correct options A . electric field inside the ball ( E_{r}=-2 alpha r ) B. electric flux passing through an imaginary sphere of radius r centre at 0 will be ( -2 pi alpha r^{4} ) C. volume charge density p(r) inside ball is ( -6 varepsilon_{0} alpha ) D. electric energy of charged ball will be ( frac{48}{5} pi varepsilon_{0} alpha^{2} R^{5} ) |
12 |

1244 | Show that no translator forces act on an electric dipole held in uniform electric field. |
12 |

1245 | The given graph shows variation (with distance r from center) of : A. Electric field of a uniformly charged sphere B. potential of a uniformly charged spherical shell C. potential of a uniformly charged sphere D. Electric field of a uniformly charged spherical shell |
12 |

1246 | ( A B C ) is a right angled triangle. Calculate the magnitude of force on charge – ( Q ) |
12 |

1247 | the point ( P, ) the flux of the electric field through the closed surface: A. will remain zero B. will becomes positive c. will become negative D. will become undefined |
12 |

1248 | A solid metal sphere of radius ( boldsymbol{R} ) has a charge ( +2 Q . ) A hollow spherical shell of radius ( 3 R ) placed concentric with the first sphere has net charge – ( boldsymbol{Q} ) A. The electric field between the spheres at a distance ( r ) from the centre of the inner sphere at ( R<r<2 R ) is ( frac{Q}{2 pi epsilon_{0} r^{2}} ) 3. The potential difference between the spheres is ( frac{Q}{3 pi epsilon_{0} R} ) c. The final distribution of charges if the spheres are joined by a conducting wire is zero on both inner and outer surfaces of the outer sphere ( D ) If the inner sphere is earthed, the charge on it is |
12 |

1249 | Mid way between the two equal and similar charges, we placed the third equal and similar charge. Which of the following statements are correct, concerned to the equilibrium along the line joining the charges? A. The third charge will experience a net force inclined to the line joining the charges. B. The third charge is in a stable equilibrium. c. The third charge is in an unstable equilibrium. D. The third charge will experience a net force perpendicular to the line joining the charges. |
12 |

1250 | The displacement of a charge ( Q ) in the electric field ( boldsymbol{E}=boldsymbol{e}_{1} hat{boldsymbol{i}}+boldsymbol{e}_{2} hat{boldsymbol{j}}+boldsymbol{e}_{3} hat{boldsymbol{k}} ) is ( hat{boldsymbol{r}}=boldsymbol{a} hat{mathbf{1}}+boldsymbol{b} hat{boldsymbol{j}} . ) The work done is- A ( Qleft(a e_{1}+b e_{2}right) ) () ( aleft(a_{1}+b_{2}right)+b_{2}+b_{2} ) в. ( Q sqrt{left(a e_{1}right)^{2}+left(b e_{2}right)^{2}} ) c. ( Qleft(e_{1}+e_{2}right) sqrt{a^{2}+b} ) D. ( Q(sqrt{e_{1}^{2}+e_{2}^{2}})(a+b) ) |
12 |

1251 | The number of electrons present in ( -1 C ) of charge is: A ( cdot 6 times 10^{18} ) B . ( 1.6 times 10^{19} ) ( c cdot 6 times 10^{19} ) D. ( 1.6 times 10^{18} ) |
12 |

1252 | An electric dipole is placed at the centre of a sphere. Mark the correct answers: This question has multiple correct options A. The flux of the electric field through the sphere is zero. B. The electric field is zero at every point of the sphere. C. The electric potential is zero everywhere of the sphere. D. The electric potential is zero on a circle on the surface. |
12 |

1253 | Three concentric conducting spherical shells of radii ( boldsymbol{R}, 2 boldsymbol{R} ) and ( boldsymbol{3} boldsymbol{R} ) carry charges ( Q,-2 Q ) and ( 3 Q, ) respectively. Compute the electric field at ( r=frac{5}{2} R ) ( A ) B. ( c ) D. |
12 |

1254 | Electric lines of forces. A. May form closed path B. Must form closed path C. May be discontinuous D. Both (a) and (c) are correct |
12 |

1255 | A body has a charge of ( -2 mu C ). If it has ( 2.5 times 10^{13} ) protons, then how many electrons the body has? A ( cdot 1.25 times 10^{13} ) B. ( 2.5 times 10^{13} ) c. ( 3.75 times 10^{13} ) D. None of these |
12 |

1256 | The electric field at a point ( 2 mathrm{cm} ) from an infinite line charge of linear charge density ( 10^{-7} mathrm{cm}^{-1} ) is? A ( cdot 4.5 times 10^{4} N C^{-1} ) B. ( 9 times 10^{4} N C^{-1} ) c. ( 9 times 10^{2} N C^{-1} ) D. ( 18 times 10^{4} N C^{-1} ) |
12 |

1257 | In conductors electrons can flow because their A . ions are free B. electrons are free and mobile c. protons are free D. negative ions are free |
12 |

1258 | Derive an expression for intensity of electric field at a point broadside position or an equatorial line of an electric dipole. |
12 |

1259 | What is the work done in moving a test charge ( q ) through a distance ( 4 mathrm{cm} ) along the equatorial axis of an electric dipole? A . 4 B. 40 ( c ) D. |
12 |

1260 | The imaging drum of a photocopier is positively charged to attract negatively charged particles of toner. Near the surface of the drum, its electric field has magnitude ( 1.4 times 10^{5} N C^{-1} . ) A toner particle is to be attached to the drum with a force that is 10 times the weight of the particle. Assume toner particles are made of carbon ( _{6}^{12} C ) Find charge to mass ratio of the charged toner particle : A ( cdot 7.0 times 10^{-4} mathrm{Ckg}^{-1} ) В. ( 7.0 times 10^{-3} mathrm{Ckg}^{-1} ) C. ( 7.0 times 10^{-5} mathrm{Ckg}^{-1} ) D. ( 7.0 times 10^{-6} mathrm{Ckg}^{-1} ) |
12 |

1261 | So that the torque acting on it is maximum. | 12 |

1262 | A particle A having a charge of ( 5.0 times ) ( 10^{-} 7 C ) is fixed in a vertical wall. ( A ) second particle ( B ) of mass 100 g and having equal charge is suspended by a silk thread of length ( 30 mathrm{cm} ) above the particle A. Find the angle of thread with the vertical when it stays in equilibrium. |
12 |

1263 | Figure shows the electric field lines around three point charges ( A, B ) and ( C ) Which charge has the largest magnitude then? ( mathbf{A} cdot A ) B. ( B ) ( c cdot C ) D. ( B ) and ( C ) have equal magnitude |
12 |

1264 | Establish the formula for electric field intensity at a point on the axis of an electric dipole. |
12 |

1265 | Two spheres having same radius and mass are suspended by two strings of equal length from the same point in such a way that their surfaces touch each other. On depositing charge ( 2 times ) ( 10^{-6} C ) on them they repel each other in such a way that in equilibrium the angle between their strings becomes ( 60^{circ} . ) If the distance from the point of suspension to the centre of the sphere is ( 10 mathrm{cm} . ) Find the mass of each sphere. ( left(boldsymbol{K}=mathbf{9} times mathbf{1 0}^{mathbf{9}} boldsymbol{S} boldsymbol{I} quad text { and } quad boldsymbol{g}=mathbf{1 0 m s}^{-1}right) ) A. ( 0.6235 k g ) в. ( 0.3117 k g ) c. ( 0.1559 k g ) D. ( 1.2468 k g ) |
12 |

1266 | An electric dipple has dipple moment ( 4 times 10^{-11} ) and the two charges have magnitudes 4 nC each. Calculate the electric field due to the dipole i) At a point on the axis at a distance ( 0.01 mathrm{m} ) from one of the charges and ii) At a point on the perpendicular bisector at a distance ( 0.02 mathrm{m} ) from the middle point. |
12 |

1267 | Find the orbital magnetic dipole moment of the electron in a hydrogen atom |
12 |

1268 | A hollow conducting sphere has a net charge of ( +Q . ) There are four labeled points all on the inside of the sphere, as shown above. Points A through D are ocated progressively closer to the center of the sphere. Which point has the largest magnitude of electric field? A. Point A B. Point B ( c . ) Point ( c ) D. Point D E. All points have the ( d ) ie |
12 |

1269 | A hollow conducting sphere is placed in an electric field produced by a point charge as shown. Let ( V_{A}, V_{B}, V_{C} ) be the electric potentials at points ( A, B, C ) respectively and ( V_{0} ) is the potential at centre 0 due to induced charge on shell. This question has multiple correct options A ( . V_{0}=0 ) В. ( V_{A}>V_{B}>V_{C} ) ( mathbf{c} cdot V_{4}=V_{B}=V_{O} ) ( mathbf{D} cdot V_{A}<V_{B}<V_{C} ) |
12 |

1270 | Three charges ( -mathbf{q}_{1},+mathbf{q}_{2} ) and ( -mathbf{q}_{3} ) are placed as shown in the figure. The ( x ) component of the force on ( -q_{1} ) is proportional to: A ( cdot frac{mathrm{q}_{2}}{mathrm{b}^{2}}-frac{mathrm{q}_{3}}{mathrm{a}^{2}} cos theta ) B. ( frac{mathrm{q}_{2}}{mathrm{b}^{2}}+frac{mathrm{q}_{3}}{mathrm{a}^{2}} sin theta ) c. ( frac{mathrm{q}_{2}}{mathrm{b}^{2}}+frac{mathrm{q}_{3}}{mathrm{a}^{2}} cos theta ) D. ( frac{mathrm{q}_{2}}{mathrm{b}^{2}}-frac{mathrm{q}_{3}}{mathrm{a}^{2}} sin theta ) |
12 |

1271 | If ( V_{0} ) be the potential at origin in an electric field ( overrightarrow{boldsymbol{E}}=boldsymbol{E}_{boldsymbol{x}} hat{boldsymbol{j}}+boldsymbol{E}_{boldsymbol{y}} hat{boldsymbol{j}}, ) then the potential at point ( boldsymbol{P}(boldsymbol{x}, boldsymbol{y}) ) is ( mathbf{A} cdot V_{0}+x E_{x}+y E_{y} ) B. ( V_{0}+x E_{x}-y E_{y} ) C ( . V_{0}-x E_{x}-y E_{y} ) D. ( sqrt{left(x^{2}+y^{2}right)} sqrt{E_{x}^{2}+E_{y}^{2}}-V_{0} ) |
12 |

1272 | A cube is arranged such that its length, breadth, height are along ( X, Y ) and ( Z ) directions. One of its corners is situated at the origin. Length of each side of the cube is ( 25 mathrm{cm} ). The components of electric field are ( E_{x}=400 sqrt{2} N / C, E_{y}=0 ) and ( E_{Z}=0 ) respectively. The flux coming out of the cube at one end, whose plane is perpendicular to ( X ) axis, will be: ( mathbf{A} cdot 25 sqrt{2} N m^{2} / C ) ( mathbf{B} cdot 5 sqrt{2} N m^{2} / C ) ( mathbf{c} cdot 250 sqrt{2} N m^{2} / C ) D. ( 25 mathrm{Nm}^{2} / mathrm{C} ) |
12 |

1273 | Multiple Correct Answers Type Let ( left[epsilon_{0}right] ) denote the dimensional formula of the permittivity of vacuum and ( left[mu_{0}right] ) that of the permeability of vacuum. If ( mathrm{M} ) ( = ) mass, ( L= ) length, ( T= ) time, and ( l= ) electric current, then This question has multiple correct options A ( cdotleft[epsilon_{0}right]=M^{-1} L^{-3} T^{2} I^{2} ) B . ( left[epsilon_{0}right]=M^{-1} L^{-3} T^{4} I^{2} ) c. ( left[mu_{0}right]=M L T^{-2} I^{-2} ) D. ( left[mu_{0}right]=M L^{2} T^{-1} I ) |
12 |

1274 | A point charge ( q ) is located at the centre of a thin ring of radius ( R ) with uniformly distributed charge -q. Find the magnitude of the electric field strength vector at the point lying on the axis of the ring at a distance ( x ) from its centre if ( x>>R ) |
12 |

1275 | If the dipole of moment ( 2.57 times ) ( 10^{-17} mathrm{C} . mathrm{m} ) is placed into an electric field of magnitude ( 3.0 times 10^{4} N / C ) such that the fields lines are aligned at ( 30^{circ} ) with the line joining the dipole, what torque will act on the dipole? A. ( 7.7 times 10^{-13} mathrm{Nm} ) B . ( 3.855 times 10^{-13} mathrm{Nm} ) ( mathbf{c} cdot 3.855 times 10^{-15} mathrm{Nm} ) D. ( 7.7 times 10^{-15} mathrm{Nm} ) |
12 |

1276 | Which of the following is not a property of charge? A. Additivity B. Quantization c. continuity D. conservation |
12 |

1277 | Who established that electric charge is quantised? A. J.J. Thomson B. William Crookes c. R.A Millikan D. Wilhelm Rontgen |
12 |

1278 | Water from a tap, maintained at a constant potential ( V ), is allowed to fall by drops of radius ( r ) through a small hole into a hollow conducting sphere of radius R standing on an insulating stand until it fills the entire sphere. Find the potential of the hollow conductor after it is completely filled with water. | 12 |

1279 | The electric field in a region is radially out ward with magnitude ( boldsymbol{E}=boldsymbol{A} boldsymbol{r} ). Find the charge contained in a sphere of radius ( 20 c m . ) Given ( A=100 V m^{-2} ) |
12 |

1280 | Quantisation of charge implies: A. charge cannot be destroyed B. charge exists on particles C. there is a minimum permissible charge on a particle D. charge, which is a fraction of a charge on an electron is not possible |
12 |

1281 | When a charged balloon is brought near a charged silk thread, the two bodies A. Repel each other B. Attract each other c. Neither attract nor repel D. None of the above |
12 |

1282 | Force of attraction between two point charges ( Q ) and ( -Q ) separated by ( d ) meter is ( F_{e} . ) When these charges are placed two identical sphere of radius ( R=0.3 d ) whose centries are ( d ) meter apart the force of attraction between them is A. Greater than ( F_{e} ) B. Equal to ( F_{e} ) c. Less than ( F_{e} ) D. None of these |
12 |

1283 | Q Type your question- axis. What would be the direction of force on a positive test charge located at the origin? ( mathbf{A} ) B. ( c ) ( D ) |
12 |

1284 | A point charge is brought in an electric field. The electric field at a nearby point: This question has multiple correct options A. Will increase if the charge is positive B. Will decrease if the charge is negative c. May increase if the charge is positive D. May decrease if the charge is negative |
12 |

1285 | Electrically charged drops of mercury fall from an altitude ( h ) into a spherical metal vessel of radius R. There is a small opening in the upper part of the vessel. The mass of each drop is ( mathrm{m} ), and the charge on the drop is Q. What will be the number n of the last drop that can still enter the sphere? |
12 |

1286 | The intensity of an electric field at some point distant ( r ) from the axis of infinity long pipe having charged per unit length as q will be: A. Proportional to ( r^{2} ) B. Proportional to ( r^{3} ) c. inversely proportional to ( r ) D. inversely Proportional to ( r^{2} ) |
12 |

1287 | Electric charges -q, -q, -q and 3q are placed at the corners of a square ABCD of length/as shown in figure. The magnitude of electric dipole moment of the system is ( A cdot sqrt{2 q} ) B. 9 ( c cdot 2 q ) D. ( 2 sqrt{2} q l ) |
12 |

1288 | The graph below shows the “x-direction” position of a charged particle flying around in space and accelerating due only to some electric field. During which time interval is the force |
12 |

1289 | Consider an infinite line charge having uniform linear charge density and passing through the axis of a cylinder. What will be the effect on the flux passing through the cylinder if the portions of the line charge outside the cylinder is removed. A. decreases B. increases c. remains same D. cannot say |
12 |

1290 | The potential at 0 is : A. zero В ( cdot frac{q}{4 pi epsilon_{0}}left[frac{1}{r}-frac{1}{R_{1}}+frac{1}{R_{2}}right] ) ( ^{mathbf{C}} cdot frac{q}{4 pi epsilon_{0}}left[frac{1}{r}-frac{1}{R_{1}}right] ) D. None of these |
12 |

1291 | Consider a thin spherical shell of radius R with its center at the origin, carrying uniform positive surface charge density. The variation of the magnitude of the electric field and the electric potential ( V(r) ) with the distance ( r ) from the center, is best represented by which ( operatorname{graph} ) ( A cdot A ) B. B ( c . c ) ( D ) |
12 |

1292 | An electric dipole of length ( 2 mathrm{cm}, ) when placed with its axis making an angle of ( 60^{circ} ) with a uniform electric field, experiences a torque of ( 6 sqrt{3} mathrm{Nm} ) Calculate the potential energy of the dipole, if it has a charge of ( pm 2 mathrm{nC} ) |
12 |

1293 | What will be the magnitude of torque on an electric dipole having dipole moment of ( 4 times 10^{-9} mathrm{cm} ) placed in a uniform electric field of intensity of ( 5 times ) ( 10^{4} N C^{-1} ) making an angle ( 180^{circ} ) with the field. A ( cdot 10^{-4} N-m ) В. ( 2 times 10^{-4} N-m ) ( c .0 ) (zero) D. ( 10^{-6} N-m ) |
12 |

1294 | The electrostatic force between two point charges ( q_{1} ) and ( q_{2} ) at separation ‘ ( r^{prime} ) is given by ( F=frac{K q_{1} q_{2}}{r^{2}} . ) The constant ( K ) A. depends on the system of units only B. depends on the medium between the charges only. c. depends on both the system of units and the medium between the charges. D. is independent of both the system of units and the medium between the charges |
12 |

1295 | When the disc of gold leaf electroscope is touched with positively charged glass rod the charge on the leaves of gold leaf electroscope is : A. positive B. negative c. neutral D. none of these |
12 |

1296 | Two uncharged bodies when rubbed against each other get charged. This is known as A. Charging by conduction B. Charging by friction c. charging by induction D. Charging by convection |
12 |

1297 | Poor conductors of electricity is/are: A. Silver B. Aluminium c. Pure water D. copper |
12 |

1298 | A charge of ( 5 times 10^{-10} C ) is given to a metal cylinder of length ( 10 mathrm{m}, ) placed in air. The electric intensity at a distance of ( 0.2 mathrm{m} ) from its axis is : A. ( 4.5 vee / ) m B. ( 45 mathrm{V} / mathrm{m} ) c. ( 450 mathrm{V} / mathrm{m} ) D. ( 100 mathrm{v} / mathrm{m} ) |
12 |

1299 | A uniform electric field ( boldsymbol{E}=mathbf{2} times ) ( 10^{3} N C^{-1} ) is acting along the positive ( x ) axis. The flux through the same square if the line normal to tis plane makes a ( 60^{circ} ) angle with the ( x ) -axis is ( begin{array}{lll}text { A. } 30 N & C^{-1} m^{2}end{array} ) B. ( 10 N quad C^{-1} m^{2} ) ( begin{array}{lll}c cdot 20 N & C^{-1} m^{2} & ^{2}end{array}^{C^{2}} ) D. ( 25 N quad C^{-1} m^{2} ) |
12 |

1300 | On to a sphere of radius ( boldsymbol{R} / 2 ) and density ( rho_{2} ) with centre at ( C_{2} ) a second solid sphere is moulded with density ( rho_{1} ) radius ( R ) and centre ( C_{1} ). Find the force experienced by a point mass ( m ) at point ( P ) at a distance ( y ) from the combination as shown. |
12 |

1301 | An electric dipole is placed at an angle of ( 30^{circ} ) with an electric field of intensity ( 2 times 10^{5} N C^{-1} . ) It experiences a torque of ( 4 N m . ) Calculate the charge on the dipole if the dipole length is ( 2 mathrm{cm} ) : ( A cdot 8 m C ) в. ( 4 m C ) ( c cdot 8 mu C ) D. ( 2 m C ) |
12 |

1302 | in which two infinitely long static line charges of constant positive line charge density ( lambda ) are kept parallel to each other. In their resulting electric field, point charges ( boldsymbol{q} ) and ( -boldsymbol{q} ) are kept in equilibrium between them. The point charges are confined to move in the ( x ) direction only. If they are given a small displacement about their equilibrium positions, then the correct statement(s) is (are) A. Both charges execute simple harmonic motion. B. Both charges will continue moving in the direction of their displacement c. Charge ( +q ) executes simple harmonic motion while charge ( -q ) continues moving in the direction of its displacement. D. Charge ( -q ) executes simple harmonic motion while charge ( +q ) continues moving in the direction of its displacement |
12 |

1303 | A cylinder of radius ( R ) and length ( L ) is placed in a uniform electric field ( boldsymbol{E} ) parallel to the cylinder axis. The total flux for the surface of the cylinder is given by : ( mathbf{A} cdot 2 pi R^{2} E ) в. ( frac{pi R^{2}}{E} ) c. ( frac{R}{E} ) D. zero |
12 |

1304 | A balloon is blown up to a radius ( R ). It is then has a positive charge ( +Q ) added to it. Air is then let out so that the radius reduces to ( R / 2 ), however, the net charge remains the same. How is the charge density affected by the reducing of the radius? A. The charge density increases. B. The charge density is unaffected. c. The charge density decreases. D. There is not enough information to answer the question |
12 |

1305 | An electric dipole of moment ( vec{p} ) is placed normal to the lines of force of electric intensity ( vec{E} ), then work done in deflecting it through an angle of ( 180^{circ} ) is: A ( . p E ) в. ( +2 p E ) c. ( -2 p E ) D. zero |
12 |

1306 | A charge is distributed over two concentric hollow spheres of radii ( boldsymbol{R} ) and ( r, ) where ( R>r, ) such that the surface densities of charges are equal ( ( sigma ) ). What is the potential at their common centre? A ( cdot frac{sigma}{varepsilon_{0}}(R+r) ) В ( cdot frac{varepsilon_{0}}{sigma}(R+r) ) c. ( frac{sigma}{varepsilon_{0}} R ) D. ( frac{sigma}{varepsilon_{0}} r ) |
12 |

1307 | A charge ( ^{prime} boldsymbol{q}^{prime} ) is placed at the centre of the line joining two equal charges. The system will be in equilibrium if ( q ) is equal to A. ( -Q / 2 ) в. ( -Q / 4 ) ( c .-4 Q ) D. ( +Q / 2 ) |
12 |

1308 | Correct the given statements: Materials which allow electric current to pass through them are called Insulators. |
12 |

1309 | A point charge is placed at the corner of a cube. The electric flux through the shaded surface is ( A cdot frac{q}{8 c_{0}} ) B. ( frac{q}{varepsilon_{0}} ) ( c cdot frac{q}{24 c} ) ( D cdot frac{q}{12 varepsilon 0} ) |
12 |

1310 | When a glass rod is rubbed with silk cloth, it acquires positive charge because: A. electrons are added to it B. electrons are removed from it c. protons are added to it D. protons are removed from it |
12 |

1311 | A charged oil drop is suspended in uniform field of ( 3 times 10^{4} V / m ) so that it neither falls nor rises. The charge on the drop will be: (Take the mass of the charge ( =mathbf{9 . 9} times ) ( left.10^{-15} mathrm{kg} text { and } g=10 m / s^{2}right) ) A . ( 3.3 times 10^{-18} mathrm{C} ) B. ( 3.2 times 10^{-18} mathrm{C} ) c. ( 1.6 times 10^{-18} mathrm{C} ) D. ( 4.8 times 10^{-18} mathrm{C} ) |
12 |

1312 | The dimensions of an atom are of the order of an Angstrom. Thus there must be large electric fields between the protons and electrons. Why then is the electrostatic field inside a conductor zero? |
12 |

1313 | 1000 small water drops each of radius ( r^{prime} ) and charge ( ^{prime} q^{prime} ) coalesce together to one spherical drop. The potential of the big drop is larger than that of the smaller drops by a factor of: A. 1000 в. 100 c. 10 D. |
12 |

1314 | Two charges when kept at a distance of ( 1 m ) apart in vacuum have some force of repulsion. If the force of repulsion between these two charges be same, when placed in an oil of dielectric constant ( 4, ) the distance of separation is : ( mathbf{A} cdot 0.25 m ) в. ( 0.4 m ) ( c .0 .5 m ) D. ( 0.6 m ) |
12 |

1315 | What happens when two straws are individually rubbed with separate sheets of paper and are brought near to each other? A. The straws attract each other B. The straws repel each other c. The straws remain indifferent of each other D. Either A or B |
12 |

1316 | A conducting ball is given a certain charge and fixed at point ( P . ) An another charge of mass ( 1 g m ) and charge ( 20 mu C ) when kept at ( Q(3 m, 9 m) ) starts moving with acceleration ( overrightarrow{boldsymbol{a}}=(1.08 hat{boldsymbol{i}}+ ) 1.44 ( hat{boldsymbol{j}} ) ) ( boldsymbol{m} boldsymbol{s}^{-2} ). The potential at ( boldsymbol{Q} ) is ( +mathbf{7 2 0} ) volt. Calculate (a) charge given to ball (b) position of the ball ( mathbf{A} cdot 6.4 times 10^{-7} C(mathrm{b})(-1.8 m, 4 m) ) B . ( 6.4 times 10^{-7} C(text { b ) }(-2.8 m, 2 m) ) C ( .7 .4 times 10^{-7} C(mathrm{b})(-1.8 m, 2 m) ) D. ( 6.4 times 10^{-7} C ) (b) ( (-1.8 m, 2 m) ) |
12 |

1317 | The bob of a pendulum of mass ( mathrm{m} ) and length I and a charge of q is in the rest position in a uniform horizontal electric field of E. The tension in the string of the pendulum is : A . ( m g ) в. ( q E ) c. ( left[(m g)^{2}+(q E)^{2}right]^{1 / 2} ) D ( cdotleft[(m g)^{2}+(q E)^{2}right]^{1 / 4} ) |
12 |

1318 | Charges ( Q ) each are placed at each of two opposite corners of a square. Charges ( q ) each are placed at each of the other two corners. Find the relation between ( q ) and ( Q, ) when the net force on Q is zero. A ( cdot_{q}=-frac{3 Q}{2 sqrt{2}} ) в. ( _{q}=+frac{Q}{2 sqrt{2}} ) c. ( _{q=-frac{Q}{sqrt{2}}} ) D. ( _{q}=-frac{Q}{2 sqrt{2}} ) |
12 |

1319 | Three infinitely charged sheets are kept parallel to ( x-y ) plane having charge densities as shown. Then the value of electric field at ( ^{prime} boldsymbol{P}^{prime} ) is: A ( frac{-4 sigma}{epsilon_{0}} ) в. ( frac{4 sigma}{epsilon_{0}} ) c. ( frac{-2 sigma}{epsilon_{0}} ) ( D cdot frac{2 sigma}{epsilon_{0}} ) |
12 |

1320 | At a certain locations, the strength of the electric field is ( 30.0 mathrm{N} / mathrm{C} ). A charge of ( 3.00 mathrm{C} ) is placed at this location. How much force does this charge experience due to the electric field? A. 90.0 N B. 10.0 c. ( 0.100 mathrm{N} ) D. 270 N/C E. ( 3.33 mathrm{N} / mathrm{C} ) |
12 |

1321 | Two charges ( Q ) and ( -2 Q ) are placed at some distance. the locus of points in the plane of the charges where the potential is zero will be A. Straight line B. Circle c. Parabola D. ellipse |
12 |

1322 | Electric switches and appliances should be tested only with A. Right hand B. Left hand c. Both hands D. Electric tester |
12 |

1323 | If ( 10^{20} ) electrons are removed from a conductor. The nature and magnitude of the charge developed on it is : ( mathbf{A} cdot+16 C ) в. ( -16 C ) ( c cdot+10 C ) D. ( -10 C ) |
12 |

1324 | In a region an electric field ( mathrm{E}=15 mathrm{N} / mathrm{C} ) making an angle of ( 30^{circ} ) with the horizontal plane is present. A ball having charge ( 2 mathrm{C}, ) mass ( 3 mathrm{kg} ) and coefficient of restitution with ground ( 1 / 2 ) is projected at an angle of ( 30^{circ} ) with the horizontal in the direction of electric field with speed ( 20 mathrm{m} / mathrm{s} ), the horizontal distance travelled by ball from first drop to the second drop is equal to ( 10 x sqrt{3} m ) The value of ( x ) is: |
12 |

1325 | charge distribution will be: ( A ) B. ( c ) D. |
12 |

1326 | If a body is charged by rubbing it, its weight A. Remains precisely constant B. Increases slightly c. Decreases slightly D. May increase or decrease slightly |
12 |

1327 | If ( I_{1} ) and ( I_{2} ) are the magnitudes if inclined current in the cases I and II respectively, then. ( mathbf{A} cdot I_{1}=I_{2} ) ( mathbf{B} cdot I_{1}>I_{2} ) ( mathbf{C} cdot I_{1}<I_{2} ) D. Nothing can be said |
12 |

1328 | When a plastic comb rubbed on hair is brought near bits of paper, it attracts them because: A. The comb and the paper get similarly charged. B. They get oppositely charged. c. The paper bits are very light. D. None of these |
12 |

1329 | The exact equation of motion of the bead along the thread is ( ^{mathbf{A}} cdot_{m} frac{d^{2} x}{d t^{2}}=–frac{k 2 Q q x}{left(x_{0}^{2}+R^{2}right)^{3 / 2}} ) B. ( quad m frac{d^{2} x}{d t^{2}}=–frac{k Q q x}{left(x_{0}^{2}+R^{2}right)^{3 / 2}} ) ( ^{mathbf{C}} cdot quad m frac{d^{2} x}{d t^{2}}=–frac{k 2 Q q x}{left(x_{0}^{2}-R^{2}right)^{3 / 2}} ) ( ^{mathrm{D}} cdot quad m frac{d^{2} x}{d t^{2}}=–frac{k Q q x}{left(x_{0}^{2}-R^{2}right)^{3 / 2}} ) |
12 |

1330 | A ( 1 mathrm{kg} ) ball is suspended in a uniform electric field with the help of a string fixed to a point. The ball is given a charge ( sqrt{5} ) coulomb and the string makes an angle ( 37^{0} ) with the vertical in the equilibrium position. In the equilibrium position the tension is double the weight of the ball. Find the magnitude of the electric field in ( mathrm{N} / mathrm{C} ) ( A cdot 6 ) B. 3 ( c cdot 2 ) D. 5 |
12 |

1331 | Aluminium metal is: A. magnetic substance B. bad conductor of heat C . good conductor of electricity D. bad conductor of electricity |
12 |

1332 | Gases begin to conduct electricity at low pressure because A. the lectrons in atoms can move freely at low pressures B. atoms break up into electrons and protons. C. colliding electrons can acquire higher kinetic energy due to increased mean free path leading to ionization of atoms. D. at low pressure gases turn into plasma. |
12 |

1333 | If a water particle of mass ( 10 mathrm{mg} ) and having a charge of ( 1.5 times 10^{-6} C ) stays suspended in a room, then the magnitude and direction of electric field in the room is A. ( 15 N / C ), vertically upwards B. 15 N/C, vertically downwards c. ( 65.3 mathrm{N} / mathrm{C} ), vertically upwards D. ( 65.3 mathrm{N} / mathrm{C} ), vertically downwards |
12 |

1334 | If the flux of the electric field through a closed surface is zero, This question has multiple correct options A. the electric field must be zero everywhere on the surface B. the electric field may be zero everywhere on the surface c. the charge inside the surface must be zero D. the charge in the vicinity of the surface must be zerç |
12 |

1335 | Three point charges ( -q, q ) and ( Q ) are arranged as given in figure:
If ( d ) is distance from centre of ( -q ) and ( +boldsymbol{q} ) to ( boldsymbol{Q} ) and ( boldsymbol{d}>>>boldsymbol{a}, ) then the |
12 |

1336 | A thin spherical conduction shell of radius R has a charge q. another charge ( mathrm{Q} ) is placed atthe centre of the shell. The electrostatic potential at a point ( mathrm{P} ) at a distance ( mathrm{R} / 2 ) from thecentre of the shell is A ( cdot frac{2 Q}{4 pi varepsilon_{0} mathrm{R}} ) в. ( frac{2 Q}{4 pi epsilon_{0} mathrm{R}}-frac{2 mathrm{q}}{4 pi varepsilon_{0} mathrm{R}} ) c. ( frac{2 mathrm{Q}}{4 pi epsilon_{6} mathrm{R}}+frac{mathrm{q}}{4 pi varepsilon_{0} mathrm{R}} ) D. ( frac{(mathrm{q}+mathrm{Q})}{4 pi varepsilon_{0}} frac{2}{mathrm{R}} ) |
12 |

1337 | A gold coin has a charge of ( +10^{-4} C . ) The number of electrons removed from it is: A ( cdot 10^{6} ) В. ( 625 times 10^{12} ) c. ( 1.6 times 10^{-25} ) D. ( 1.6 times 10^{13} ) |
12 |

1338 | If ( F_{g} ) and ( F_{e} ) are gravitational and electrostatic forces between two electrons at a distance ( 0.1 m ) then ( boldsymbol{F}_{boldsymbol{g}} / boldsymbol{F}_{e} ) is in the order of A ( cdot 10^{43} ) B . ( 10^{-43} ) ( mathbf{c} cdot 10^{35} ) D. ( 10^{-35} ) |
12 |

1339 | Which of the following instruments is used for detecting electric charge? A. Ammeter B. Galvanometer c. Electroscope D. None of the above |
12 |

1340 | An electric dipole is placed at the centre of a sphere. Mark the correct options: A. The electric field is zero at every point of the sphere B. The flux of the electric field through the sphere is nonzero c. The electric field is zero on a circle on the sphere D. The electric field is not zero anywhere on the sphere |
12 |

1341 | Two concentric spheres kept in air have radii ‘R’ and ‘r’. They have similar charge and equal surface charge density’ ( sigma^{prime} ) The electric potential at their common centre is. ( left(epsilon_{0}= ) permittivity of free right. space ( ) ) A ( cdot frac{sigma(R+r)}{epsilon_{0}} ) в. ( frac{sigma(R-r)}{epsilon_{0}} ) c. ( frac{sigma(R+r)}{2 epsilon_{0}} ) D. ( frac{sigma(R+r)}{4 epsilon_{0}} ) |
12 |

1342 | Three charged particles are in equilibrium under their electrostatic forces only. which of the following statements is true for the system. This question has multiple correct options A. the particles have the same charge B. all the charges cannot have the same magnitude c. all the charges cannot have the same sign D. the equilibrium is unstable |
12 |

1343 | A woolen cloth when rubbed against plastic object acquires charge. A. Sometimes positive and sometimes negative B. Negative c. Positive D. None of the these |
12 |

1344 | Two metallic spheres of radii ( 1 mathrm{cm} ) and ( 3 c m ) are given charges of ( -1 times 10^{-2} C ) and ( 5 times 10^{-2} C, ) respectively. If these are connected by a conducting wire, the final charge on the bigger sphere is- A ( cdot 3 times 10^{-2} mathrm{C} ) B. ( 4 times 10^{-2} mathrm{C} ) c. ( 1 times 10^{-2} C ) D. ( 2 times 10^{-2} C ) |
12 |

1345 | An electric dipole placed with its axis in the direction of a uniform electric field experiences: ( A ). a force but not torque B. a torque but no force c. a force as well as a torque D. neither a force nor a torque |
12 |

1346 | In charging by conduction, the charged object A. ends up oppositely charged to the object used to charge it. B. ends up similarly charged to the object used to charge it. C. discharges the object used to charge it, completely. D. discharges the object used to charge it, to some extent |
12 |

1347 | A proton of mass ( m ) charge ( e ) is released from rest in a uniform electric field of strength ( E . ) The time taken by it to travel a distance ( d ) in the field is : A ( cdot sqrt{frac{2 d e}{m E}} ) в. ( sqrt{frac{2 d m}{E e}} ) c. ( sqrt{frac{2 d E}{m e}} ) D. ( sqrt{frac{2 E e}{d m}} ) |
12 |

1348 | Q Type your question_ two charges is represented by the field lines also shown in the diagram. What signs do the two charges have, and which charge is stronger? A. Charge 1 is positive, Charge 2 is negative and the stronger charge is Charge 1 B. Charge 1 is positive, Charge 2 is negative, and both charges have the same strength. C. Charge 1 is negative, Charge 2 is positive, and the stronger charge is Charge 1 D. Charge 1 is negative, Charge 2 is positive, and both charges have the same strength. E. Charge 1 is positive, Charge 2 is negative, and the stronger charge is Charge 2 |
12 |

1349 | Two tiny spheres, each of mass ( M, ) and charges ( +boldsymbol{q} ) and ( -boldsymbol{q} ) respectively, are connected by a massless rod of length, L. They are placed in a uniform electric field an an angle ( theta ) with the ( vec{E}left(theta=0^{circ}right) ) Calculate the minimum time in which the dipole axis becomes parallel to the field line. |
12 |

1350 | A positively charged rod is brought near the disc of a positively charged gold leaf electroscope. State your observation A. Divergence increases. B. Divergence decreases. c. Divergence remains same D. cant say |
12 |

1351 | A particle that carries a charge ( -q ) is placed at rest in uniform electric field ( 10 N / C . ) It experiences a force and moves in a certain time ( t, ) it is observed to acquire a velocity ( 10 vec{i}-10 vec{j} mathrm{m} / mathrm{s} ). The given electric field intersects a surface of area ( A m^{2} ) in the ( X ) -Z plane. Electric flux through surface is: в. ( 5 A N m^{2} / C ) c. ( sqrt{2} A N m^{2} / C ) ( mathbf{D} cdot 2 sqrt{5} A N m^{2} / C ) |
12 |

1352 | When a body is negatively charged by friction, it means A. the body has acquired excess of electrons B. the body has acquired excess of protons C. the body has lost some electrons D. the body has lost some neutrons |
12 |

1353 | The potential of outer shell is ( A cdot frac{q}{32 pi epsilon 0^{a}} ) B. ( frac{q}{16 pi epsilon a} ) ( c cdot frac{q}{8 pi cos ^{a}} ) ( D cdot frac{q}{4 pi varepsilon a a} ) |
12 |

1354 | If a body is charged by rubbing it, its weight : A. Remains precisely constant B. Increase slightly c. Decrease slightly D. May increase slightly or may decrease slightly |
12 |

1355 | A rectangular tank of mass ( m_{o} ) and charge ( Q ) over it is placed over a smooth horizontal floor. A horizontal electric field ( E ) exist in the region. Rain drops are falling vertically in the tank at the constant rate of ( n ) drops per second Mass of each drop is m. Find velocity of ( operatorname{tank} ) as function of time. |
12 |

1356 | Stat law of conservation of charges? | 12 |

1357 | What is the ratio of electric field intensity at distance ( 5 mathrm{cm} ) to that at 10 ( mathrm{cm} ) from a point charge ( Q ) in air? A . 2: 1 B. 1: 2 c. 4: 1 D. 1: 4 |
12 |

1358 | When a body is charged, its mass: A. increases B. decreases c. remains same D. none of these |
12 |

1359 | A charge ( Q ) is placed at the centre of the open end of a cylindrical vessel of radius ( R ) and height ( 2 R ) as shown in figure. The flux of the electric field through the surface (curved surface ( + ) base) of the vessel is A ( cdot frac{Q}{epsilon_{0}} ) в. ( frac{Q}{2 E_{0}}left(1+frac{1}{sqrt{2}}right) ) c. ( frac{Q}{4 epsilon_{0}} ) D. ( frac{Q}{sqrt{5} epsilon_{0}} ) |
12 |

1360 | An electric dipole when placed in a uniform electric field will have minimum potential energy, if the angle between dipole moment and electric field is A . zero B. ( frac{pi}{2} ) ( c . pi ) D. ( frac{3 pi}{2} ) |
12 |

1361 | A charge ( q ) is placed at the centre of the open end of cylindrical vessel. The flux of electric field through the surface of the vessel is A . 0 в. ( frac{q}{epsilon_{0}} ) c. ( frac{q}{2 epsilon_{0}} ) D. ( frac{2 q}{epsilon_{0}} ) |
12 |

1362 | Glass wool is a ….. conductor of electricity. A . goodd B. badd c. very good D. None of the above |
12 |

1363 | Identify the conductors from the following: Eraser, paper, matchstick, copper wire, polythene A . eraser B. copper wire c. paper D. polythene |
12 |

1364 | toppr Q Type your question- of the electric field and the electric potential ( V(r) ) with the distance ( r ) from the centre, is best represented by which graph ? ( A ) ( B ) ( c ) ( D ) |
12 |

1365 | The electric flux passing through a hemispherical surface of radius ( mathrm{R} ) placed in an electric field E with its axis parallel to the filed is : ( mathbf{A} cdot pi R^{2} E ) В. ( 2 pi R^{2} E ) c. ( 2 pi R E ) ( mathbf{D} cdot 2 pi R^{3} E ) |
12 |

1366 | A cube of side ( 10 mathrm{cm} ) encloses a charge of ( 0.1 mu C ) at its centre.What is the number of lines of force through each face of the cube A ( cdot 1.13 times 10^{11} ) В. ( 1.13 times 10^{6} ) c. ( 1.13 times 10^{23} ) D. 1883 |
12 |

1367 | The above diagrams show the electric field lines of charged particles. Identify which of the following drawing represents field lines between two parallel plates? A. Drawing B. Drawing II c. Drawing III D. Drawing IV E. Drawing V |
12 |

1368 | The specific charge of a proton is ( 9.6 times ) ( 10^{7} C / k g . ) The specific charge of an alpha particle will be: ( mathbf{A} cdot 9.6 times 10^{7} C / k g ) B . ( 19.2 times 10^{7} C / k g ) ( mathbf{c} cdot 4.8 times 10^{7} C / k g ) D. ( 2.4 times 10^{7} C / k g ) |
12 |

1369 | An electron and a proton equal momenta, enter a uniform magnetic filed at right angles to the field lines. What will be the ratio of the radii of an vature of three trajectories. A . 1: 1 B. 1: 2 c. 2: 3 D. 3: 4 |
12 |

1370 | A charge ( q ) is located at the centre of a cube. The electric flux through any face is : A ( cdot frac{pi q}{6left(4 pi varepsilon_{0}right)} ) в. ( frac{q}{6left(4 pi varepsilon_{0}right)} ) c. ( frac{4 pi q}{6left(4 pi varepsilon_{0}right)} ) D. ( frac{4 pi q}{frac{1}{6}left(4 pi varepsilon_{0}right)} ) |
12 |

1371 | toppr ( mathbf{G} ) Q Type your question the plates As some of the oil evaporates, the droplet loses mass and starts to accelerate. Its charge remains constant. In which direction does the droplet accelerate, and which change needs to be made to the separation of the plates in order to stop this acceleration? separation of the direction of acceleration downwards downwards upwards decrease D upwards increase ( A cdot A ) B. B ( c cdot c ) D. D |
12 |

1372 | An electric dipole is placed in an electric field generated by a point charge. Choose the correct option: A. the net electric force on the dipole must be zero B. the net electric force on the dipole may be zero C. the torque on the dipole due to the field must be zero D. the torque on the dipole due to the field is not equal to zero |
12 |

1373 | You are provided with a negatively charged gold leaf electroscope. What is the effect on the gold leaves when a glass rod rubbed with silk is brought near the disc of electroscope? A. Divergence increases B. Divergence decreases c. Divergence remains same D. Can not be determined |
12 |

1374 | There is an electric field ( overrightarrow{mathrm{E}}=frac{a x^{3} hat{i}+b y^{4} widehat{j}+c z^{2} widehat{k}}{a x^{4}+b y^{5}+c z^{3}} ) at any ( (x, y, z) ) coordinates in the space except origin, Where a,b & c are constant. Find the electrostatic flux passing through a sphere of radius R whose center is at the origin. ( mathbf{A} cdot pi R ) ( mathbf{B} cdot 2 pi R ) ( mathbf{c} .4 pi R ) D. Zero |
12 |

1375 | The adjoining figure shows a negatively charged electroscope. If a negatively charged rod is brought close to, but not touching, the knob, the two leaves will : A. move closer together B. move farther aparttt c. not move at all D. None of these |
12 |

1376 | A mass of 1 kg carrying a charge of ( 2 C ) is accelerated through a potential of ( 1 mathrm{V} ) The velocity acquired by it is? A ( cdot sqrt{2} m s^{-1} ) B . ( 2 m s^{-1} ) c. ( frac{1}{sqrt{2}} m s^{-1} ) D. ( frac{1}{2} m s^{-1} ) |
12 |

1377 | The region between two concentric spheres of radii a and ( b(>a) ) contains volume charge density ( rho(r)= ) ( C ) ( boldsymbol{r} ) where ( C ) is a constant and ( r ) is the radial distance, as shown in figure. A point charge ( q ) is placed at the origin, ( r= ) O.Find the value of ( C ) for which the electric field in the region between the spheres is constant (i.e., r independent) |
12 |

1378 | The minimum charge on an object is: A. 1 coulomb B. 1 stat coulomb C ( .1 .6 times 10^{-20} ) coulomb D. ( 1.6 times 10^{-19} ) coulomb |
12 |

1379 | What is the nature of electric charge? A . only positive B. only negative c. positive and negative both D. neutral. |
12 |

1380 | Equal charges ( Q ) are placed at the four corners ( A, B, C ) and ( D ) of a square of length ( a ). The magnitude of the force on the charge at ( B ) will be ( ^{mathrm{A}} cdot frac{3 Q^{2}}{4 pi varepsilon_{0} a^{2}} ) В. ( frac{4 Q^{2}}{4 pi varepsilon_{0} a^{2}} ) c. ( frac{k Q^{2}}{a^{2}}left(frac{2 sqrt{2}+1}{2}right) ) D ( cdotleft(2+frac{1}{sqrt{2}}right) frac{3 Q^{2}}{4 pi varepsilon_{0} a^{2}} ) |
12 |

1381 | Find the electric field at a distance ( x ) from the centre inside the shell. ( mathbf{A} cdot E=0 ) в. ( quad E=frac{Q}{4 pi epsilon_{0} a^{2}} ) c. ( _{E}=frac{Q}{4 pi epsilon_{0} x^{2}} ) D. ( _{E}=frac{Q}{4 pi epsilon_{0}(a-x)^{2}} ) |
12 |

1382 | An electric dipole consists of charges ( pm 2.0 times 10^{-8} C ) separated by a distance of ( 2.0 times 10^{-3} m ). It is placed near a long line charge of linear charge density ( 4.0 times 10^{-4} C quad m^{-1} ) as shown in the figure, such that the negative charge is at a distance of ( 2.0 mathrm{cm} ) from the line charge. The force acting on the dipole will be A. ( 7.2 N ) towards the line charge B. ( 6.6 N ) away from the line charge c. ( 0.6 N ) away from the line charge D. ( 0.6 N ) towards the line charge |
12 |

1383 | The particles which can be added to the nucleus of an atom, without changing properties, are called. A. Neutrons B. Electrons c. Protons D. None of these |
12 |

1384 | An electric dipole when placed in a uniform electric field ( boldsymbol{E} ) will have a minimum potential energy if the dipole moment makes the following angle with ( boldsymbol{E} ) ( A ) В. ( pi / 2 ) c. zero D. ( 3 pi / 2 ) |
12 |

1385 | Two small identical conducting balls ( A ) and ( mathrm{B} ) of charges ( +10 mu mathrm{C} ) and ( +30 mu mathrm{C} ) respectively, are kept at a separation of ( 50 mathrm{cm} . ) These balls have been connected by a wire for a short time. The final charge on each of the balls ( A ) and ( B ) will be: A ( . ) 10 ( mu mathrm{C} ) and ( 30 mu mathrm{C} ), respectively B. 20 muC on each ball c. ( 30 mu mathrm{c} ) and ( 10 mu mathrm{C} ), respectively D. -40 muC and 80 muC, respectively |
12 |

1386 | Which statement best explains why a rubber rod becomes negatively charged when rubbed with fur? A. The rubber that the rod is made of is a better insulator than fur. B. The fur is a better insulator than the rubber. C. Molecules in the rubber rod have a stronger attraction for electrons than the molecules in the fur. D. Molecules in the fur have a stronger attraction for electrons than the molecules in the rubber rod. |
12 |

1387 | Q Type your question- body of mass ( mathrm{m} ) and charge ( mathrm{q} ) is placed perpendicular to the centre of sqaure at a distance ( h ) from the centre. Take the distance between centre and vertices of the sqaure to be ‘ ( a ) ‘. What should be the value of ( Q ) in order that this body may be in equilibrium? A ( cdot pi varepsilon_{0} frac{m g}{2 h q}left(h^{2}+2 a^{2}right)^{3 / 2} ) B. ( pi varepsilon_{0} frac{m g}{h q}left(h^{2}+a^{2}right)^{3 / 2} ) c. ( pi varepsilon_{0} frac{2 m g}{h q}left(h^{2}+2 a^{2}right)^{3 / 2} ) P. ( quad frac{m g}{h q}left(h^{2}-a^{2}right)^{3 / 2} ) |
12 |

1388 | A positively charged rod is touched with the brass disc of a positively charged gold leaf electroscope. State the effect on divergence of the leaves. A. Divergence increases B. Divergence decreases c. Divergence remains same D. none |
12 |

1389 | A charge ( Q ) is divided into two parts of ( q ) and ( Q-q . ) If the Coulomb repulsion between them when they are separated, is to be maximum, the ratio of ( frac{Q}{q} ) should be: A .2 в. ( 1 / 2 ) ( c cdot 4 ) D. ( 1 / 4 ) |
12 |

1390 | The rod or stem of a gold leaf electroscope is made of A. wood B. Brass c. Glass D. Ebonite |
12 |

1391 | A small isolated conductor has a large positive charge. What is true of the electric field and the |
12 |

1392 | Define one “Coulomb”‘ on the basis of Coulomb’s law. |
12 |

1393 | A charge ( Q ) is to be distributed on two objects, ( A ) and ( B ). The values of the charges on the objects are such that the force between the objects will be maximum. The ratio ( Q_{A}: Q_{B} ) will be A . 1: 1 B. 1: 2 c. 1: 3 D. 1: 4 |
12 |

1394 | The electric field ( vec{E} ) in the overlapped region is A. non-uniform c. ( frac{p}{3 varepsilon_{0}} ) D. ( frac{-p}{3 varepsilon_{0}} ) |
12 |

1395 | Formula of coloumbs inverse square law is (using electric charges), assume ( k=frac{1}{4 pi epsilon_{0}} ) A. ( F=q_{1} q_{2} d^{2} cdot K ) B. ( F=frac{q_{1} q_{2}}{K d^{2}} ) ( ^{mathrm{c}} cdot_{F}=frac{sqrt{K} q_{1} q_{2}}{d^{2}} ) D. None of these |
12 |

1396 | 6. A charged oil drop is suspended in a uniform field of 3 x 104 V/m so that it neither falls nor rises. The charge on the drop will be (take the mass of the charge as 9.9 x 10-15 kg and g = 10 m/s) (a) 3.3 x 10-18C (b) 3.2 x 10-18 C (c) 1.6 x 10-18 C (d) 408 x 1018 C (AIEEE 2004) |
12 |

1397 | The magnitude of electric field as a function of the distance r inside the sphere is given by : ( ^{mathbf{A}} cdot_{E}=frac{rho_{0}}{varepsilon}left[frac{r}{3}-frac{r^{2}}{4 R}right] ) B. ( quad E=frac{rho_{0}}{varepsilon}left[frac{r}{4}-frac{r^{2}}{3 R}right] ) ( ^{mathrm{C}}=frac{rho_{0}}{varepsilon}left[frac{r}{3}+frac{r^{2}}{4 R}right] ) D. ( quad E=frac{rho_{0}}{varepsilon}left[frac{r}{4}+frac{r^{2}}{3 R}right. ) |
12 |

1398 | Which material is a best conductor? A . silver B. porcelain c. rubber D. gold |
12 |

1399 | The electric field in a region of space is given by ( vec{E}=(hat{5} i+hat{2} j) N c^{-1} . ) The electric flux due to this field through an area ( 2 m^{2} ) lying in the ( Y ) -Z plane in S.I. units is A . 10 B. 20 c. ( 10 sqrt{2} ) 2 D. ( 2 sqrt{29} ) |
12 |

1400 | Calculate the electric potential at the center of the square in figure. |
12 |

1401 | In instantaneous current in a metallic wire is ( mathrm{i}=(5+10 mathrm{t}) mathrm{A} ) then find amount of charge flown through it from ( t=2 s ) to ( t=3 s ) is A . 100 B. 24C c. ( 30 c ) D. 40C |
12 |

1402 | Three large plates are arranged as shown. How much charge will flow through the key ( K ) if it is closed? ( A cdot frac{5 Q}{6} ) в. ( frac{4 Q}{3} ) ( c cdot frac{3 Q}{2} ) D. None of these |
12 |

1403 | The figure shows three concentric metallic spherical shells. The outermost shell has charged ( q_{2}, ) the innermost shell has charged ( q_{1} ), and the middle shell is undercharged. The charge appearing on the inner surface of the outermost shell is A ( cdot(a) q_{1}+q ) [ q ] B. ( (b) frac{q}{2} ) ( c cdot(c)-q ) ( D cdot(d) ) Zero |
12 |

1404 | Define intensity of electric field at a point. Derive an expression for the electric field intensity due to a point charge. |
12 |

1405 | Point charges each of magnitude ( Q ) are placed at three corners of a square as shown in the diagram. What is the direction of the resultant |
12 |

1406 | Gases are good conductors of electricity This question has multiple correct options A . low pressure B. high pressure c. low temperature D. high temperature |
12 |

1407 | What will be the nature of charge on the metal paper clip of electroscope when a positively charged body is brought in contact with it? A. Positive B. Negative c. Partially negative D. None of the above |
12 |

1408 | A given charge ( q ) is situated at a certain distance from a small electric dipole in the end on position experiences a force F. If the distance of the charge is doubled, the force acting on the charge will become: A ( .2 F ) B. ( F / 2 ) c. ( F / 4 ) D. ( F / 8 ) |
12 |

1409 | In induction the charge induced in the near surface of a dielectric is: A. equal and similar B. greater and dissimilar c. lesser and dissimilar D. equal and dissimilar |
12 |

1410 | The electrical potential on the surface of a sphere of radius ( ^{prime} r^{prime} ) due to a charge ( 3 times ) ( 10^{-6} ) is ( 500 V ). The intensity of electric field on the surface of the sphere is ( left[frac{1}{4 pi varepsilon_{0}}=9 times 10^{9} N m^{2} C^{-2}right]left(i n N C^{-1}right) ) A ( .250 / 27 ) B. ( 27 / 250 ) ( c .250 ) D. 27 |
12 |

1411 | A dipole of moment ( vec{p} ) is placed in a uniform electric field ( vec{E} ). If the force on the dipole is ( vec{F} ) and the torque is ( vec{tau} ). Then This question has multiple correct options ( mathbf{A} cdot vec{F}=0 ) B . ( vec{F}=|vec{p}| vec{E} ) ( mathbf{c} cdot|vec{tau}|=vec{p} . vec{E} ) D . ( vec{tau}=vec{p} times vec{E} ) |
12 |

1412 | A beam of protons is deflected sideways. could this deflections be caused a.) By an electric field b) by a magnetic field c.) if either could be responsible how would you be able to tell which was present |
12 |

1413 | What is NOT an example of an insulator in the kitchen? A. An oven mitt B. A wooden spoon c. Pots and pans D. A plastic measuring cup |
12 |

1414 | A copper slab of mass ( 2 g ) contains ( 2 x ) ( 10^{22} ) atoms. The charge on the nucleus of each atom is ( 29 e . ) What fraction of the electrons must be removed from the sphere to give it a charge of ( +2 mu C ? ) A ( .58 times 10^{22} ) B. ( 1.25 times 10^{13} ) c. ( 2.16 times 10^{11} ) D. ( 2.16 times 10^{-11} ) |
12 |

1415 | The surface that have zero flux are ( mathbf{A} cdot S_{2}, S_{4}, ) and ( S_{5} ) B. ( S_{1}, S_{3}, S_{4} ) and ( S_{6} ) ( c cdot S_{1}, S_{2}, ) and ( S_{3} ) ( mathrm{D} cdot S_{2}, S_{3}, ) and ( S_{4} ) |
12 |

1416 | An insulated charged sphere of radius ( 5 c m ) has a potential of ( 10 V ) at the surface. The potential at the centre will be : A. Same as that at ( 5 mathrm{cm} ) from the surface B. Same as that at ( 25 mathrm{cm} ) from the surface ( c .10 V ) D. Zero |
12 |

1417 | On the axis and on the equator of an electric dipole for all points A. On both of them ( V neq 0 ) B. On both of them ( V=0 ) c. on the axis ( V=04 $ a n d o )nequatorv Vneq o$s D. on the axis ( V neq 0 ) and on equator ( V=0 ) |
12 |

1418 | Find out the angle ( theta ) made by string from vertical in equilibrium position A ( cdot tan ^{-1}left(frac{m g}{q E}right) ) B. ( sin ^{-1}left(frac{m g}{q E}right) ) c. ( cos ^{-1}left(frac{m g}{q E}right) ) ( tan ^{-1}left(frac{q E}{m g}right) ) |
12 |

1419 | For the situation shown in the figure below, match the entries of column with the entries of column II | 12 |

1420 | ( 1 mu C ) charge is uniformly distributed on a spherical shell given by equation ( boldsymbol{x}^{2}+boldsymbol{y}^{2}+boldsymbol{z}^{2}=mathbf{2 5} . ) What will be intensity of electric field at a point (1,1,2)( ? ) |
12 |

1421 | Differentiate between NPN & PNP transistors.? |
12 |

1422 | A ( 100 mathrm{W} ) bulb produces an electric field of ( 2.9 mathrm{V} / mathrm{m} ) at a point ( 3 mathrm{m} ) away. If the bulb is replaced by ( 400 mathrm{W} ) bulb without disturbing other conditions, then the electric field produced at the same point is A ( .2 .9 mathrm{V} / mathrm{m} ) в. ( 3.5 V / m ) c. ( 4 V / m ) D. ( 5.8 V / m ) |
12 |

1423 | Q Type your question conducting rod of length I. Another point particle of the same mass is attached to the other end of the rod. The two particles carry charges ( +q ) and ( -q ) respectively. This arrangement is held in a region of a uniform electric field ( mathrm{E} ) such that the rod makes a small angle ( theta ) (say of about 5 degrees) with the field direction. Find an expression for the minimum time needed for the rod to become parallel to the field after it is set free. A ( cdot frac{pi}{2}, sqrt{frac{M L}{2 q E}} ) В ( cdot frac{pi}{2}, sqrt{frac{M L}{q E}} ) c. ( pi, sqrt{frac{M L}{q E}} ) D. None of these |
12 |

1424 | Two small, identical spheres having ( +boldsymbol{Q} ) and ( -Q ) charge are kept at a certain distance ( F ) force acts between the two If in the middle of two spheres, another similar sphere having ( +Q ) charge is kept, then it experiences a force in magnitude and direction as A. Zero having no direction B. ( 8 F ) towards ( +Q ) charge c. ( 8 F ) towards ( -Q ) charge D. ( 4 F ) towards ( +Q ) charge |
12 |

1425 | A positively charged rod is brought near an uncharged conductor. If the rod is then suddenly withdrawn, the charge left on the conductor will be : A. positive B. negative c. zero D. data insufficient |
12 |

1426 | Two mutually perpendicular long straight conductors carrying uniformly distributed charges of linear charge densitites ( lambda_{1} ) and ( lambda_{2} ) are positioned at a distance a from each other. How does the interaction between the rods depend on a? |
12 |

1427 | Find the electric field at a distance ” ( z ” ) from the plane. This question has multiple correct options A ( cdot vec{E}=frac{sigma}{2 epsilon_{0}} hat{k} ) for ( z>0 ) B・ ( vec{E}=-frac{sigma}{2 epsilon_{0}} hat{k} ) for ( z>0 ) c. ( vec{E}=frac{sigma}{2 epsilon_{0}} hat{k} ) for ( z<0 ) D・ ( vec{E}=-frac{sigma}{2 epsilon_{0}} hat{k} ) for ( z<0 ) |
12 |

1428 | Substances which allow heat to pass through them easily are known as A. Insulators B. Conductors c. semi conductors D. None |
12 |

1429 | Two charges of ( +1 mu C &+5 mu C ) are placed ( 4 c m ) apart, the ratio of the force exerted by both charges on each other will be – A . 1: 1 B. 1: 5 c. 5: 1 D. 25: 1 |
12 |

1430 | toppr Q Type your question below. For which figure the net force on the charge may be zero ( A ) B. ( c ) ( D ) |
12 |

1431 | toppr Q Type your question 4 B ( c ) D. None of these |
12 |

1432 | Define electric flux. Write its Sl unit. | 12 |

1433 | Which one of the following statements is CORRECT? A. Lightning rods are made of insulators B. A conductor holds charge c. The earth is an insulator D. An insulator prevents charge from flowing |
12 |

1434 | Three point charges of ( 2 q,-q ) and ( -q ) are placed at the corner of an equilateral triangle of side a. Then: This question has multiple correct options A. the potential at the centroid of the triangle is zero B. the electric field at the centroid of triangle is zero c. the dipole moment of the system is ( sqrt{2} q a hat{j} ) D. the dipole moment of the system is ( sqrt{3} q a hat{j} ) |
12 |

1435 | State Gauss’s Law in Electrostatics. | 12 |

1436 | A sphere of radius ( R ) has a volume density of charge ( rho=k r, ) where ( r ) is the distance from the centre of the sphere and ( k ) is constant. The magnitude of the electric field which exits at the surface of the sphere is given by: ( left(varepsilon_{0}=text { permittivity of free space }right) ) A ( cdot frac{4 pi k R^{2}}{3 varepsilon_{0}} ) B. ( frac{k R}{3 varepsilon_{0}} ) c. ( frac{4 pi k R}{varepsilon_{0}} ) D. ( frac{k R^{2}}{4 varepsilon_{0}} ) |
12 |

1437 | Graphite is a conductor of electricity because A . it has free valence electrons B. it is a non-metal form of Carbon. c. it is an allotrope of Carbon. D. Both A and B |
12 |

1438 | State whether true or false: Rain water is a non-conductor of electricity. A. True B. False |
12 |

1439 | The total flux associated with given cube will be- where ( ^{prime} boldsymbol{a}^{prime} ) is side of cube ( :left(frac{mathbf{1}}{boldsymbol{epsilon}_{mathbf{0}}}=mathbf{4} boldsymbol{pi} timesright. ) ( 9 times 10^{9} ) SI unit) A ( cdot 162 pi times 10^{-3} N m^{2} / C ) B . ( 162 pi times 10^{3} mathrm{Nm}^{2} / mathrm{C} ) C ( cdot 162 pi times 10^{-6} N m^{2} / C ) D. ( 162 pi times 10^{6} mathrm{Nm}^{2} / mathrm{C} ) |
12 |

1440 | A point charge ( +q ) is placed at the centre of a cube of side ( L ). The electric flux emerging from the cube is ( ^{mathrm{A}} cdot frac{q}{varepsilon_{0}} ) B. zero c. ( frac{6 q L^{2}}{varepsilon_{0}} ) D. ( frac{q}{6 L^{2} varepsilon_{0}} ) |
12 |

1441 | If the radius of a sphere doubled without changing the charge on it, then electric flux originating form the sphere is: A . Double B. Half c. same D. zero |
12 |

1442 | The Sl unit of solid angle is A. radians B. steradians c. degrees D. All of the above |
12 |

1443 | Electric charge is developed due to actual transfer of A . electron B. proton c. neutron D. none |
12 |

1444 | What do you molar by electric change? | 12 |

1445 | Electrons are charge carriers in conductors. A . True B. False |
12 |

1446 | A long cylindrical wire carries a linear charge density of ( 3 times 10^{-8} mathrm{Cm}^{-1} . ) An electron revolve around it in a circular path under the influence of the attractive force. ( K E ) of the electron is : A . ( 1.44 times 10^{-7} J ) В . ( 2.88 times 10^{-17} J ) D. ( 8.64 times 10^{-17} J ) |
12 |

1447 | Given a uniform electric field ( boldsymbol{E}=mathbf{5} times ) ( 10^{3} hat{i} N / C . ) What would be the flux through the same square if the plane makes an angle of ( 30^{circ} ) with the ( x ) -axis? A. ( 5 N m^{2} / C ) B. ( 25 N m^{2} / C ) ( mathbf{c} cdot 50 N m^{2} / C ) D. ( 500 mathrm{Nm}^{2} / mathrm{C} ) |
12 |

1448 | Lightning wants to get to ground. It will follow the path(s) of to do so. A. most impedance B. least impedance c. least distance D. least inductance |
12 |

1449 | There point charges of ( +2 mu C,-3 mu C,-3 mu C quad ) are kept at the vertices ( A, B ) and ( C ) respectively of an equilateral triangle of side ( 20 mathrm{cm} ) as shown in the figure.What should be the sign and magnitude of the charge to be placed at the mid – point (M) of side BC so that the charge at A remains in equilibrium? |
12 |

1450 | What is the magnitude of a point charge due to which the electric field ( 30 c m ) away has the magnitude 2 Newton/coulomb? ( [1 / 4 pi varepsilon 0=9 times ) ( left.mathbf{1 0}^{mathbf{9}} mathbf{N m}^{mathbf{2}}right] ) A ( cdot 2 times 10^{-1} c ) coulomb B. ( 3 times 10^{11} ) coulomb c. ( 5 times 10^{11} ) coulomb D. ( 9 times 10^{11} ) coulomb |
12 |

1451 | A solid sphere of radius ( R_{1} ) and volume charge density ( rho=frac{rho_{0}}{r} ) is enclosed by a hollow sphere of radius ( R_{2} ) with negative surface charge density ( sigma ), such that the total charge in the system is zero, ( rho_{0} ) is positive constant and ( r ) is the distance from the centre of the sphere. The ratio ( frac{R_{2}}{R_{1}} ) is A ( cdot frac{sigma}{rho_{0}} ) В. ( sqrt{2 sigma / rho_{0}} ) C ( cdot sqrt{rho_{0} / 2 sigma} ) D. ( frac{rho_{0}}{sigma} ) |
12 |

1452 | Name a metal among the following having highest heat conductivity. A . Silver B. Copper c. Aluminium D. Brass |
12 |

1453 | State the kind of charge on a negative ion: A. positive B. negative c. zero D. cant say |
12 |

1454 | A charge ( q ) is released in presence of electric (E) and magnetic field (B) then after some time its velocity is v then:- ( A cdot V propto E ) в. ( v propto frac{1}{E} ) ( c cdot V^{2} propto E ) D. ( V propto B^{circ} ) |
12 |

1455 | The electric field intensity at point 0 is A. zero В ( cdot frac{q}{4 pi epsilon_{0}}left[frac{1}{r^{2}}-frac{1}{R_{1}^{2}}+frac{1}{R_{2}^{2}}right] ) c. ( frac{q}{4 pi epsilon_{0}}left[frac{1}{r^{2}}-frac{1}{R_{1}^{2}}right] ) D. None of these |
12 |

1456 | When an ebonite rod is rubbed with fur the charge acquired by the fur is A. Positive B. Negative c. No charge D. Can’t say |
12 |

1457 | Three concentric spherical metallic shells ( A, B ) and ( C ) of ( operatorname{radii} a, b ) and ( c(a< ) ( b<c) ) have charge densities ( sigma,-sigma ) and ( sigma ) respectively. If the shells ( A ) and ( C ) are at the same potential then the relation between ( a, b ) and ( c ) is : A ( a+b+c=0 ) 0 B . ( a+c=b ) ( mathbf{c} cdot a+b=c ) ( mathbf{D} cdot a=b+c ) |
12 |

1458 | Mercury is a good conductor of heat.State true or false. A . True B. False |
12 |

1459 | Two large thin metal plates are parallel and close to each other. On their inner faces, the plates have surface charge densities of opposite signs and magnitude ( 27 times 10^{-22} C quad m^{-2} . ) The electric field ( overrightarrow{boldsymbol{E}} ) in region II in between the plates is ( begin{array}{ll}text { A } cdot 4.25 times 10^{-8} N & C^{-1}end{array} ) в. ( 6.28 times 10^{-10} N quad C^{-1} ) ( begin{array}{lll}text { с. } 3.05 times 10^{-10} N & C^{-1}end{array} ) ( begin{array}{lll}text { D } cdot & 5.03 times 10^{-10} N & C^{-1}end{array} ) |
12 |

1460 | What happens when a charged balloon is placed near another balloon of the same charge? A. Attract each other B. Repel each other c. Neither attract nor repel D. All of the above |
12 |

1461 | Electric flux over a surface in an electric field may be: A. positive B. negative c. zero D. positive, negative, zero |
12 |

1462 | Three charges ( 29,-q .-q ) are located at the vertices of an equilateral triangle. At the triangle A . field is zero but potential is non-zero B. field is non- zero and potential are zero. c. Both field potential are zero D. Both field potential are non zero |
12 |

1463 | Sometimes you get a mild spark when you touch the metal surface of a car. What might be the reason? A. Due to magnetic attraction, a spark is created B. Due to electrostatic charge residing on the metal as well as on skin, mild spark is observed C. Car tries to become neutral by donating electrons D. Its the only path to ground |
12 |

1464 | Find the electric field in the region labelled 2. ( mathbf{A} cdot k_{e} frac{q}{r^{2}} ) ( mathbf{B} cdot 2 k_{e} frac{q}{r^{2}} ) ( c cdot 3 k_{e} frac{q}{r^{2}} ) D. ( 4 k_{e} frac{q}{r^{2}} ) |
12 |

1465 | Electric field in a region is given by ( overrightarrow{boldsymbol{E}}=-4 boldsymbol{x} hat{boldsymbol{i}}+boldsymbol{6} boldsymbol{y} hat{boldsymbol{j}}, ) find the charge enclosed in cube of side 1 m oriented as shown in figure. ( 4 cdot 2 varepsilon ) B. ( c cdot varepsilon ) D. ( 6 varepsilon ) |
12 |

1466 | A dipole is placed in a uniform electric field with its axis parallel to the field. It experiences: A. both a net force and torque B. only a net force c. neither a net force nor a torque D. only a torque |
12 |

1467 | Using Gausss law derive an expression for the electric field intensity at any point near a uniformly charged thin wire of charge/length as ( 1 mathrm{C} / mathrm{m} ) |
12 |

1468 | Find the net electric flux through the entire cube |
12 |

1469 | In a certain region of space, electric field is along the z-direction throughout The magnitude of electric field is, however, not constant but increases uniformly along the positive z-direction, at the rate of ( 10^{5} N C^{-1} m^{-1} ) per metre. What are the force and torque experienced by a system having a total dipole moment equal to ( 10^{-7} mathrm{Cm} ) in the negative z-direction? |
12 |

1470 | An example in which light emitting diodes are used is : A. calculator B. hard drive c. optical drive D. analog watch |
12 |

1471 | A spherically symmetric charge distribution is characterised by a charge density having the following variation: ( boldsymbol{p}(boldsymbol{r})=boldsymbol{p}_{o}left(mathbf{1}-frac{r}{R}right) ) for ( boldsymbol{r}<boldsymbol{R} ) ( boldsymbol{p}(boldsymbol{r})=mathbf{0} ) for ( boldsymbol{r} geqslant boldsymbol{R} ) Where ( r ) is the distance from the centre of the charge distribution and ( p_{o} ) is a constant. The electric field at an internal point ( ^{text {A }} cdot frac{p_{o}}{4 epsilon_{o}}left(frac{r}{3}-frac{r^{2}}{4 R}right) ) в. ( frac{p_{o}}{epsilon_{o}}left(frac{r}{3}-frac{r^{2}}{4 R}right) ) c. ( frac{p_{o}}{3 epsilon_{o}}left(frac{r}{3}-frac{r^{2}}{4 R}right) ) D. ( frac{p_{o}}{12 epsilon_{o}}left(frac{r}{3}-frac{r^{2}}{4 R}right) ) |
12 |

1472 | Figure shows the field produced by two point charges ( +q ) and ( -q ) of equal magnitude but opposite signs ( (a n ) electric dipole). Find the electric flux through each of the closed surfaces ( A ) B, C and D. |
12 |

1473 | A sphere of radius ( r ) has a volume density of charge ( rho=k r . ) Find the electric field intensity at the surface of the sphere. A. ( frac{4 pi k R^{4}}{3 epsilon_{0}} ) в. ( frac{k R}{3 epsilon_{0}} ) c. ( frac{4 pi k R}{epsilon_{0}} ) D. ( frac{k R^{2}}{4 epsilon_{0}} ) |
12 |

1474 | A electric dipole moment ( overrightarrow{boldsymbol{p}}= ) ( (2.0 hat{i}+3.0 hat{j}) mu C . m ) is placed in a uniform electric field ( overrightarrow{boldsymbol{E}}= ) ( (3.0 hat{i}+2.0 hat{k}) times 10^{5} N C^{-1} ) This question has multiple correct options A. The torque that ( vec{E} ) exerts on ( vec{p} ) is ( (0.6 hat{i}-0.4 hat{j}-0.9 hat{k}) N m ) B. The potential energy of the dipole is -0.65 c. The potential energy of the dipole is ( 0.6 J ) D. If the dipole is free to rotate in the electric field, the maximum magnitude of potential energy of the dipole during the rotation is 1.3 .5 |
12 |

1475 | What is an electric dipole? | 12 |

1476 | A charge q is distributed over two spheres of radii ( R ) and ( r ) such that their surface densities are equal. What is the ratio of the charges on the spheres? A ( cdot frac{r}{R} ) в. ( frac{r^{2}}{R^{2}} ) c. ( frac{r^{3}}{R^{3}} ) D. ( frac{r^{4}}{R^{4}} ) |
12 |

1477 | Surface density of charge on a sphere of radius ( R ) in terms of electricity intensity ( E ) at a distance ( r ) in free space is ( left(epsilon_{0}=text { permittivity of free space }right) ) ( ^{mathrm{A}} cdot_{epsilon_{0} E}left(frac{R}{r}right)^{2} ) в. ( frac{epsilon_{0} E R}{r^{2}} ) ( ^{mathbf{C}} epsilon_{0} Eleft(frac{r}{R}right)^{2} ) D. ( frac{epsilon_{0} E r}{R^{2}} ) |
12 |

1478 | The magnitude of the average electric field normally present in the atmosphere just above the surface of the Earth is about ( 150 N / C ), directed inward towards the center of the Earth. This gives the total net surface charge carried by the Earth to be : [Given ( epsilon_{0}= ) ( mathbf{8 . 8 5} times mathbf{1 0}^{-12} mathbf{C}^{2} / mathbf{N}-boldsymbol{m}^{2}, boldsymbol{R}_{E}=mathbf{6 . 4} times ) ( mathbf{1 0}^{mathbf{6}} boldsymbol{m} ) A ( .+660 k C ) в. ( -660 k C ) ( c .-680 k C ) D. ( +680 k C ) |
12 |

1479 | A glass rod is rubbed with silk, is found positively charged. This is because. A. Electrons are transferred from glass rod to silk. B. Electrons are transferred from silk to glass rod. c. Protons are transferred from glass rod to silk. D. Protons are transferred from silk to glass rod. |
12 |

1480 | Electric potential at a point ( P, r ) distance away due to a point charge ( q ) at ( A ) is ( V ) volts. If twice of this charge is distributed uniformly on the surface of a hollow sphere of radius ( 4 r ) with center at point ( A, ) the potential at ( P ) now is : ( A cdot v ) B. V/2 ( c cdot v / 4 ) D. v/8 |
12 |

1481 | The electric potential at a point situated at a distance r on the axis of a short electric dipole of moment p will be ( mathbf{1} / mathbf{4}left(boldsymbol{pi} varepsilon_{mathbf{0}}right) ) times ( A cdot p / r^{3} ) B. plre ( c cdot p / r ) D. none of the above |
12 |

1482 | A charge ( (5 sqrt{2}+2 sqrt{5}) ) coulomb is placed on the axis of an infinite disc at a distance a from the centre of disc. The flux of this charge on the part of the disc having inner and outer radius of a and 2a will be : A ( cdot frac{3}{2 varepsilon_{0}} ) в. ( frac{1}{2 varepsilon_{0}} ) c. ( frac{2[sqrt{5}+sqrt{2}]}{varepsilon_{0}} ) D. ( frac{2 sqrt{5}+5 sqrt{2}}{2 varepsilon_{0}} ) |
12 |

1483 | In finding the electric field using Gauss law the formula ( |overrightarrow{boldsymbol{E}}|=frac{boldsymbol{q}_{e n c}}{in_{mathbf{0}}|boldsymbol{A}|} ) is applicable. In the formula ( in_{0} ) is permittivity of free space, ( boldsymbol{A} ) is the area of Gaussian surface and ( q_{e n c} ) is charge enclosed by the Gaussian surface. This equation can be used in which of the following situation? A. For any choice of Gaussian surface. B. Only when the Gaussian surface is an equipotential surface and ( |vec{E}| ) is constant on the surface. C. Only when ( |vec{E}|= ) constant on the surface D. Only when the Gaussian surface is an equipotential surface. |
12 |

1484 | A positively charged particle having some mass is resting in equilibrium at a height H above the center of a fixed, uniformly and positively charged ring of radius R. The force of gravity (mg) acts downwards. The equilibrium of the particle at the given position (H) for small vertical displacement will be: (Assume ( g ) is uniform) ( ^{mathbf{A}} cdot ) stable if ( H<frac{R}{2} ) B. stable if ( H=frac{R}{sqrt{2}} ) c. unstable if ( H<frac{R}{sqrt{2}} ) D. stable if ( H=frac{R}{2} ) |
12 |

1485 | ( A ) and ( B ) are two points on the axis and the perpendicular bisector respectively of an electric dipole. A and B are far away from the dipole and at equal distances from its centre. The fields at ( A ) and ( mathrm{B} ) i.e. ( overrightarrow{boldsymbol{E}_{A}} quad ) and ( overrightarrow{boldsymbol{E}_{B}} ) are respectively such that ( mathbf{A} cdot overrightarrow{E_{A}}=overrightarrow{E_{B}} ) B . ( overrightarrow{E_{A}}=2 overrightarrow{E_{B}} ) c. ( overrightarrow{E_{A}}=-2 overrightarrow{E_{B}} ) D. ( overrightarrow{E_{A}}=frac{1}{2} overrightarrow{E_{B}} ) |
12 |

1486 | The adjoining figure shows a negatively charged electroscope. If a positively charged rod touches the knob, the two leaves will A. move closer together B. move farther apart c. not move at all D. become positively chargedd |
12 |

1487 | When we wear nylon dresses during winter then there is which gets produced due to contact with out body. Fill in the Blank. A. Magnetic B. Electrostatic c. Potential D. kinetic |
12 |

1488 | and mass ( 1 k g ) are placed (fixed) symmetrically about a movable central charges of magnitude ( 5 times 10^{-5} C ) and mass ( 0.5 k g ) as shown. The charge at ( P_{1} ) is removed. The acceleration of the central charge is ( left[text { Given } boldsymbol{O} boldsymbol{P}_{1}=boldsymbol{O} boldsymbol{P}_{2}=boldsymbol{O} boldsymbol{P}_{3}=boldsymbol{O} boldsymbol{P}_{4}=right. ) ( O P_{5}=1 m ; frac{1}{4 pi varepsilon_{0}}=9 times 10^{9} ) in ( S I ) units ( A cdot 9 m s^{-2} ) upwards B. ( 9 m s^{-2} ) downwards c. ( 4.5 m s^{-2} ) upwards D. ( 4.5 m s^{-2} ) downwards |
12 |

1489 | In the thunderstorm, the charges accumulate near the upper edges of clouds are A . negatively charged B. positively chargedd c. neutral D. none of these |
12 |

1490 | Iron have much lower specific heat than: A. steel B. Copper c. water D. none of the above |
12 |

1491 | An electron falls through a distance of ( 1.5 c m ) in a uniform electric field of magnitude ( 2 times 10^{4} N / C . ) Now the direction of the field is reversed keeping the magnitude and unchanged and a proton falls through the same distance. Compute the time of fall in each case, neglecting gravity. |
12 |

1492 | The electric field between the inside and outside layers is: A ( cdot 10^{6} V m^{-1} ) В. ( 5 times 10^{6} V m^{-1} ) c. ( 0.2 times 10^{7} V m^{-1} ) D. ( 10^{7} V m^{-1} ) |
12 |

1493 | Which of the following statements are not true? This question has multiple correct options A. All charges at rest tend to move higher electric potential to lower electric potential B. All charges at rest tend to move lower electric potential to higher electric potential C. Positive charges at rest tend to move form lower electric potential to higher electric potential and negative charges at rest tend to move from higher electric potential to lower electric potential D. Positive charges at rest tend to move from higher potential to lower potential and negative charges at rest tend to move from lower electric potential to higher potential |
12 |

1494 | A solid conducting sphere having charge ( 4 mu C ) is placed on nonconducting stand. A point charge ( 2 mu C ) is placed at a distance from the centre of the sphere, at a double distance of radius of the sphere as shown in the figure. If conducting sphere is earthed then charge flow into the ground is : ( A cdot 5 mu C ) B. ( 2 mu C ) ( c cdot 10 mu C ) D. ( 1 mu C ) |
12 |

1495 | Five balls numbered 1,2,3,4,5 are suspended using reparate threads. The balls (1,2),(2,4) and (4,1) show electrostatic attraction, while (2,3) and (4,5) show repulsion. Therefore, ball 1 must be A. negatively charged B. positively chargedd c. neutral D. made of metal |
12 |

1496 | During a physics lab, a plastic strip was rubbed with cotton and became positively charged. The correct explanation for why the plastic strip becomes positively charged is that A. the plastic strip acquired extra protons from the cotton. B. the plastic strip acquired extra protons during the charging process c. protons were created as the result of the charging process D. the plastic strip lost electrons to the cotton during the charging process |
12 |

1497 | Equipotential surface due to an electric dipole A. Does not exist B. Bisects the line joining two charge of the diople c. contains the two charge of the dipole D. Exists in an axial plane |
12 |

1498 | An electric dipole of momentum ( vec{p} ) is placed in a uniform electric field. The dipole is rotated through a very small angle ( theta ) from equilibrium and is released, find the time period of simple harmonic motion | 12 |

1499 | Figure represents a negatively charged gold leaf electroscope. The distribution of charges on the different parts will be as: A. ( A, D ) and ( E ) will have positive charges. ( B ) and ( C ) will have no charge B. A, D and E will have negative charges. B and C will have no charge C. ( A, D ) and ( E ) will have negative charges. B and ( C ) will have positive charges. D. A, D and E will have positive charges. B and C will have negative charges |
12 |

1500 | A solid insulating sphere of radius a carries a net positive charge ( 3 Q ) uniformly distributed throughout its volume. Concentric with this sphere is a conducting spherical shell with inner radius ( n ) and outer radius ( c ) and having a net charge ( -Q ), as shown in figure. The electric field in the region ( b>r>a ) is |
12 |

1501 | If charges ( boldsymbol{q} / 2 ) and ( 2 q ) are placed at the centre of face and at the corner of a cube, then the total flux through the cube will be: A ( cdot frac{q}{2 varepsilon_{0}} ) в. ( frac{q}{varepsilon_{0}} ) c. ( frac{q}{6 varepsilon_{0}} ) D. ( frac{q}{8 varepsilon_{0}} ) |
12 |

1502 | A gold leaf electroscope is given a positive charge so that its leaves diverge. How is the divergence of leaves affected, when an uncharged rod is brought near its disc? A. divergence increases B. divergence decreases c. divergence remains same D. can’t say |
12 |

1503 | 2 | 12 |

1504 | If the electric flux entering and leaving an enclosed surface respectively is ( phi_{1} ) and ( phi_{2}, ) the electric charge inside the surface will be : ( mathbf{A} cdotleft(phi_{2}-phi_{1}right) varepsilon_{0} ) B. ( frac{left(phi_{2}+phi_{1}right)}{varepsilon_{0}} ) c. ( frac{left(phi_{2}-phi_{1}right)}{varepsilon_{0}} ) ( mathbf{D} cdotleft(phi_{2}+phi_{1}right) varepsilon_{0} ) |
12 |

1505 | Which wall is at higher potential? A. Inner B. Outer c. Both at same potential D. None |
12 |

1506 | In some old texts it is mentioned that ( 4 pi ) lines of force originate from each unit positive charge. Comment on the statement in view of the fact that ( 4 pi ) is not an integer. |
12 |

1507 | Positive electric flux indicates that electric lines of force are directed from a point charge. A. Outwards B. Onwards c. Outwards or inwards D. None of these |
12 |

1508 | A body has a positive charge of ( 8 x ) ( 10^{-19} mathrm{C} . ) It has : A. an excess of 5 electrons B. a deficiency of 5 electrons c. an excess of 8 electrons D. a deficiency of 8 electrons |
12 |

1509 | Electric charges ( boldsymbol{q}, boldsymbol{q} ) and ( -boldsymbol{2} boldsymbol{q} ) are placed at the corners of an equilateral triangle ( A B C ) of side ( L . ) The magnitude of electric dipole moment of the system is ( mathbf{A} cdot q L ) в. ( 2 q L ) c. ( (sqrt{3}) q L ) D. ( 4 q L ) |
12 |

1510 | Two charges ( +20 mu C ) and ( -20 mu C ) are placed ( 10 m m ) apart. The electric field at point ( P, ) on the axis of the dipole ( 10 mathrm{cm} ) away from its centre ( boldsymbol{O} ) on the side of the positive charge is ( mathbf{A} cdot 8.6 times 10^{9} N quad C^{-1} ) B . ( 4.1 times 10^{6} N quad C^{-1} ) C ( .3 .6 times 10^{6} N^{-1} ) D . ( 4.6 times 10^{5} N quad C^{-1} ) |
12 |

1511 | The electric field for ( r<R_{1} ) is given by ( boldsymbol{E}=frac{boldsymbol{X} boldsymbol{Q}}{boldsymbol{pi} varepsilon_{0} boldsymbol{r}^{2}}left[frac{r^{3}-boldsymbol{R}_{1}^{3}}{boldsymbol{R}_{2}^{3}-boldsymbol{R}_{1}^{3}}right] . ) Find ( boldsymbol{X} ) | 12 |

1512 | A charge ( Q ) is uniformly distributed over a rod of length ( l ). Consider a hypothetical cube of edge ( l ) with the centre of the cube at one end of the rod. Find the minimum possible flux of the electric field through the entire surface of the cube. |
12 |

1513 | Charge on an electron is : ( mathbf{A} cdot+e ) в. ( -e ) ( c . pm e ) D. All |
12 |

1514 | The force of interaction (attraction or repulsion) between two stationary point charges in vacuum is directly proportional to the product of the charges and inversely proportional to the square of distance between them. This is called A. Curie’s Law B. Coulomb’s law c. Faraday’s Law D. Amperr’s Law |
12 |

1515 | Assertion Three equal charges are situated on a circle of radius r such that they form on equilateral triangle, then the electric field intensity at the centre is zero Reason The force on unit positive charge at the centre, due to the three equal charges are represented by the three sides of a triangle taken in the same order Therefore, electric field intensity at centre is zero A. Both Assertion and Reason are correct and Reason is the correct explanation for Assertion B. Both Assertion and Reason are correct but Reason is not the correct explanation for Assertion c. Assertion is correct but Reason is incorrect D. Assertion is incorrect but Reason is correct |
12 |

1516 | If the terminal of a gold-leaf electroscope is grounded by touching it with a finger, A. the gold leaves spread apart in a ‘v” B. the gold leaves close together. c. there is no effect on the gold leaves. D. None of the above |
12 |

1517 | Consider a spherical Gaussian surface of radius ( r>c, ) the net charge enclosed by this surface is ( Y times Q ). Find out the value of ( boldsymbol{Y} ) ? |
12 |

1518 | The ratio of the energy required to set up in cube of side ( 10 mathrm{cm} ) uniform magnetic field of ( 4 W b / m^{2} ) and a uniform electric field of ( 10^{6} V / m ) is: A ( cdot 1.4 x 10^{7} ) B. ( 1.4 x 10^{5} ) c. ( 1.4 x 10^{6} ) D. ( 1.4 x 10^{3} ) |
12 |

1519 | A ring of diameter dis rotated in a uniform electric field until be position of maximum electric flux is found. The flux is found to be ( phi ). If the electric field strength is ( boldsymbol{E}=frac{boldsymbol{X} boldsymbol{phi}}{pi d^{2}} . ) Find out ( boldsymbol{X} ) ? |
12 |

1520 | Calculate the amount of work done in turning an electric dipole of dipole moment ( 3 times 10^{-8} C ) -m from its position of unstable equilibrium to the position of stable equilibrium in a uniform electric field of intensity ( 10^{3} N C^{-1} ) |
12 |

1521 | A circular disc of radius 0.2 meter is placed in a uniform magnetic field of ( frac{1}{pi} ) ( boldsymbol{w} boldsymbol{b} / boldsymbol{m}^{2} ) in such way that its axis makes an angle of ( 60^{circ} ) with ( vec{B} ). The magnetic flux linked with the disc is? A. 0.08 wb B. 0.01 wb ( c .0 .02 mathrm{wb} ) D. 0.06 wb |
12 |

1522 | Write down Gauss’s theorem of electrostatics. Find out intensity of the electric field at a point outside a uniformly charged thin spherical shell with its help. |
12 |

1523 | A dipole of dipole moment ( P ) is placed at a distance r form a point change ( Q ) (as shown in figure).Choose the incorrect statement. A. Torque acting on the dipole is zero B. Force acting on the dipole due to the electrie field produce by ( mathrm{Q} ) is zero C. potential energy of the dipole due to the point charge ( Q ) is ( frac{Q p}{4 frac{Q_{0}}{r^{2}}} ) D. Force acting on the dipole due to the point charge ( mathrm{Q} ) is ( frac{Q p}{4 pi varepsilon_{0} r^{3}} ) |
12 |

1524 | Potential due to an electric dipole is represented by: (where ( p ) is the dipole moment, ( r(>> ) 2a) is the distance at which the potential ( V ) of the dipole is calculated and ( theta ) is the angle between the distance vector and the dipole.) A ( cdot V=frac{p cos theta}{4 pi epsilon_{c} r^{4}} ) B. ( V=frac{p sin theta}{4 pi epsilon_{o} r^{2}} ) c. ( V=frac{p sin theta}{4 pi epsilon_{o} r^{4}} ) D. ( V=frac{p cos theta}{4 pi epsilon_{o} r^{2}} ) |
12 |

1525 | An electric dipole made up of a positive and negative charge, each of ( 1 mu C ) separated by a distance of ( 2 mathrm{cm} ), is placed in an electric field of ( 10^{5} N / C ).The work done in rotating the dipole from the position of stable equilibrium through an angle of ( 180^{0} ) is : A ( cdot 2 times 10^{-3} ) Joule B . ( 2 times 10^{-8} ) Joule c. ( 4 times 10^{-3} ) Joule D. Zero |
12 |

1526 | Charge is distributed within a sphere of radius R with a volume charge density ( rho(r)=frac{A}{r^{2}} e^{-2 r / a}, ) where ( A ) and a are constants. If ( Q ) is the total charge of this charge distribution, the radius R is: A ( cdot frac{a}{2} log left(1-frac{Q}{2 pi a A}right) ) B. ( operatorname{alog}left(1-frac{Q}{2 pi a A}right) ) ( ^{mathbf{C}} operatorname{alog}left(frac{1}{1-frac{Q}{2 pi a A}}right) ) ( ^{mathrm{D}} cdot_{overline{2}}^{a} log left(frac{1}{1-frac{Q}{2 pi a A}}right) ) |
12 |

1527 | Complete the following sentences: Like charges ( ldots ldots, ) while unlike charges each other. A . attract, attract B. repel, repel c. attract, repel D. repel, attract |
12 |

1528 | A system has two charges ( boldsymbol{q}_{boldsymbol{A}}=boldsymbol{2 . 5} times ) ( mathbf{1 0}^{-7} boldsymbol{C} ) and ( boldsymbol{q}_{B}=-mathbf{2 . 5} times mathbf{1 0}^{-mathbf{7}} boldsymbol{C} ) located at points ( boldsymbol{A}:(mathbf{0}, mathbf{0}, mathbf{1 5} mathbf{c m}) ) and ( boldsymbol{B} ) ( (0,0,+15 c m), ) respectively. What are the total charge and electric dipole moment of the system? |
12 |

1529 | One point electric charge ( Q ) is placed at the point ( P . A ) closed surface is placed near the point ( P . ) The electrical flux passing through a closed surface will be ( mathbf{A} cdot Q epsilon_{0} ) В . ( epsilon_{0} / Q ) ( c cdot Q / epsilon_{0} ) D. zero |
12 |

1530 | A charge ‘ ( q ) ‘ is placed exactly mid way between two charges ‘Q’ and ‘ ( Q ) ‘ separated by a distance ( 2 r ) in air. The force on the charge ‘ ( q ) ‘ is : A. ( frac{2 Q}{4 pi epsilon_{0} r^{2}} ) в. ( frac{Q}{4 pi epsilon_{0} r^{2}} ) c. ( Z e r o ) D. ( frac{5 Q}{4 pi epsilon_{0} r^{2}} ) |
12 |

1531 | What is the electric flux through a cube of side ( 1 mathrm{cm} ) whose encloses an electric dipole? |
12 |

1532 | What happens when two inflated balloons are rubbed with a silk cloth and brought close to each other? A. Balloons repel each other B. Balloons attract each other C. Balloons neither attract nor repel. D. Baloons either attract or repel |
12 |

1533 | Sl unit of permittivity is: ( mathbf{A} cdot F m^{-1} ) В. ( N m^{2} C^{-2} ) c. ( N m^{2} C^{-1} ) D. ( A m^{-1} ) |
12 |

1534 | A charge ‘Q’ is placed at the centre of a hemispherical surface of radius ‘ ( boldsymbol{R} ). The flux of electric field due to charge ‘ ( Q^{prime} ) through the surface of hemisphere is ( mathbf{A} cdot Q / 4 varepsilon_{0} ) в. ( Q / 4 pi varepsilon_{0} ) c. ( Q / 2 varepsilon_{0} ) D. ( Q / 2 pi varepsilon_{0} ) |
12 |

1535 | Six charges are placed at the corner of a regular hexagon as shown. If an electron is placed at the centre ( 0, ) force on it will be: A. zero B. along OF c. along oc D. none of these |
12 |

1536 | Which is a better method to find out if a body possesses charge? A. Attraction test B. Repulsion test c. Either A or B D. None of the above |
12 |

1537 | An electric charge is held at rest in a region of space filled with non-uniform magnetic field. As soon as it is left free. A. it will move in the direction of the field B. it will move opposite to the direction of the field c. it will move perpendicular to the direction of the field D. it will remain at rest |
12 |

1538 | The handles of cooking vessels are covered with plastic or wood because: A. They are beautiful. B. It is customary c. They are good conductors of heat D. They are bad conductors of heat |
12 |

1539 | State whether the given statement is True or False : Positive electrification is due to deficiency of electrons. A. True B. False |
12 |

1540 | Find the electric field for ( mathbf{0}<boldsymbol{r}<boldsymbol{R} ) ( ^{mathbf{A}} cdot_{E}=frac{rho_{0} r^{2}}{3 R epsilon_{0}} ) В. ( quad E=frac{rho_{0} r^{2}}{4 R epsilon_{0}} ) ( ^{mathrm{C}} E=frac{rho_{0} r^{2}}{2 R epsilon_{0}} ) D. ( quad E=frac{rho_{0} r^{2}}{R epsilon_{0}} ) |
12 |

1541 | ( mathbf{X} ) and ( mathrm{Y} ) are large, parallel conducting plates close to each other. Each face has an area A. X is given a charge Q.Y is without any charge. Point ( A, B ) and ( C ) are as shown in the figure. Which statement is wrong. A . The field at B is ( frac{Q}{2 frac{6}{80 A}} ) B. The field at B is ( frac{Q}{6 mathrm{c} A} ) C. The fields at ( A, B ) and ( C ) are of the same magnitude. D. The fields at A and C are of the same magnitude, but in opposite directions |
12 |

1542 | The diagram shows four charges ( q_{1}, q_{2}, q_{3}, ) and ( q_{4} ) all lying in the plane of the page. The diagram also shows the dotted circle that represents the crosssection of a spherical Gaussian surface Point ( P ) is a single point on that surface Which of the charges contributes to the electric field at point ( P ? ) ( mathbf{A} cdot q_{1} ) and ( q_{3} ) ( mathbf{B} cdot q_{2} ) and ( q_{4} ) ( mathbf{c} cdot q_{1} ) and ( q_{2} ) ( mathbf{D} cdot q_{3} ) and ( q_{4} ) E ( . q_{1}, q_{2}, q_{3}, ) and ( q_{4} ) |
12 |

1543 | Three charges ( mathbf{q}_{1}=mathbf{3} mathbf{m} mathbf{C}, mathbf{q}_{2}=-mathbf{3} mathbf{m} mathbf{C} ) and ( q_{3} ) are kept at the vertices of a triangle as shown in the figure. If the net force acting on ( q_{1} ) is ( bar{F} ), the charge ( q_{3} ) would have the magnitude ( left(1+frac{1}{n}right)^{2} m C ) So, ( n ) is: ( mathbf{A} cdot mathbf{8} ) B. 4 ( c cdot 1 ) D. 16 |
12 |

1544 | The moment directed along positive ( x- ) axis of electric field at point ( (2,2 sqrt{2}, 0) ) A. Along positive ( x- ) axis B. Along positive ( y- ) axis c. Along negative ( x- ) axis D. along negative y-axis |
12 |

1545 | Two bulbs, one of ( 200 mathrm{W} ) and the other of ( 100 mathrm{W}, ) are connected in series with a 100V battery which has no internal resistance. Then A. the current passing through the 200 W bulb is more than that through the 100 w bulb B. the power dissipation in the 200 W bulb is more than that in the 100 W bulb c. the voltage drop across the 200 W bulbs is more than that across the ( 100 mathrm{W} ) bulb D. the power dissipation in the 100 W bulb is more than that in the ( 200 mathrm{w} ) bulb |
12 |

1546 | A positive point charge is released from rest at a distance ( r_{0} ) from a positive line charge with uniform density. The speed (v) of the point charge, as a function of instantaneous distance r from line charge, is proportional to :- A ( cdot v propto e^{+r / r_{0}} ) В ( cdot v propto ln left(frac{r}{r_{0}}right) ) c. ( v proptoleft(frac{r}{r_{0}}right) ) D. |
12 |

1547 | Two point charges ( +8 q ) and ( -2 q ) are located at ( x=0 ) and ( x=L ) respectively. The location of a point on the ( x ) axis at which the net electric field due to these two point charge is zero is – A. 2 B. L/4 ( c cdot 8 L ) D. 4 L |
12 |

1548 | The electric field intensity at a point ( boldsymbol{P} ) due to point charge ( q ) kept at point ( Q ) is ( 24 N C^{-1} ) and the electric potential at point is ( 12 J C^{-1} . ) The order of magnitude of charge ( q ) is A ( cdot 10^{-6} C ) B. ( 10^{-7} C ) ( mathbf{c} cdot 10^{-10} C ) D. ( 10^{-9} C ) |
12 |

1549 | In the given figure, what is the force on the charge ( Q ) kept at ( O ) which is at the mid point of the line ( A B ? ) A ( cdot frac{2 q Q}{pi varepsilon_{0} r^{2}} ) along ( B A ) B. ( frac{2 q Q}{pi varepsilon_{0} r^{2}} ) along ( A B ) c. zero D. ( frac{q Q}{4 pi varepsilon_{0} r^{2}} ) |
12 |

1550 | Electric intensity due to an electric dipole varies with distance ( r ) as ( E alpha r^{n}, ) where ‘n” is A. -3 B. -2 c. -1 D. 0 |
12 |

1551 | Find force on semicircular ring due to point charge ( boldsymbol{q} ) |
12 |

1552 | The figure shows three infinite nonconducting plates of charge perpendicular to the plane of the paper with charge per unit area ( +sigma,+3 sigma ) and ( -sigma . ) The ratio of the net electric field at that point ( A ) to that at point ( mathrm{B} ) is ( 1 / x ). Find ( x ) |
12 |

1553 | In uniform electric field, ( boldsymbol{E}=mathbf{1 0} boldsymbol{N} boldsymbol{C}^{-1} ) as shown in figure. Find. ( (mathrm{i}) boldsymbol{V}_{boldsymbol{A}}-boldsymbol{V}_{boldsymbol{B}} ) (ii) ( V_{B}-V_{C} ) A . -10,20 B. 30,50 ( c .-20,30 ) D. 40,50 |
12 |

1554 | Gauss’s law is valid for A. any closed surface B. only regular close surface C . any open surface D. only irregular open surfaces |
12 |

1555 | A charge ( Q ) is located at the centre of a sphere of radius ( R ) Calculate the flux going out through the surface of the sphere ( ^{A} cdot frac{Q}{4 pi epsilon_{0} R^{2}} ) в. ( frac{Q}{4 pi epsilon_{0} R} ) c. ( frac{Q}{4 pi R^{2}} ) D. ( underline{Q} ) |
12 |

1556 | Obtain the expression of the electric field due to an infinitely long linear charged wire along the perpendicular distance from the wire. |
12 |

1557 | The Sl unit of volume charge density is ( mathbf{A} cdot C m^{-1} ) в. ( C m^{-2} ) ( mathrm{c} cdot mathrm{Cm}^{-3} ) ( mathbf{D} cdot C m^{-4} ) |
12 |

1558 | If a electric flux leaving and entering from closed surface are ( phi ) and ( phi ) respectively, then the charge associated with closed surface will be A ( cdot frac{phi_{2}-phi_{1}}{varepsilon_{0}} ) B. ( frac{phi_{1}+phi_{2}}{varepsilon_{0}} ) c. ( frac{phi_{1}-phi_{2}}{varepsilon_{0}} ) D ( cdot varepsilon_{0}left(phi_{2}-phi_{1}right) ) |
12 |

1559 | A glass rod rubbed with silk is used to charge a gold leaf electroscope and the leaves are observed to diverge. The electroscope thus charged is exposed to X-rays for a short period. Then: A. the divergence of leaves will not be affected B. the leaves will diverge further c. the leaves will collapse D. the leaves will melt |
12 |

1560 | What do you mean by conservation charges? | 12 |

1561 | Explain conservation of charge giving two examples | 12 |

1562 | A point charge ( +q ) is placed at the centre of a cube of side ( L ). The electric flux emerging from the cube is A ( cdot frac{q}{varepsilon_{0}} ) B. Zero c. ( frac{6 q L^{2}}{varepsilon_{0}} ) D. ( frac{q}{6 L^{2} varepsilon_{0}} ) |
12 |

1563 | Consider a uniform spherical charge distribution of radius ( R_{1} ) centred at the origin ( 0 . ) In this distribution, a spherical cavity of radius ( R_{2}, ) centre at ( P ) with distance ( boldsymbol{O P}=boldsymbol{alpha}=boldsymbol{R}_{1}-boldsymbol{R}_{2} ) is made. If the electric field inside the cavity at position ( vec{r} ) is ( vec{E}(vec{r}), ) then the correct statement(s) is (are) A ( cdot vec{E} ) is uniform, its magnitude is independent of ( R_{2} ) but its direction depends on ( vec{r} ) B. ( vec{E} ) is uniform, its magnitude is depends on ( R_{2} ) and its direction depends on ( vec{r} ) C. ( vec{E} ) is uniform, its magnitude is independent of ( alpha ) but its direction depends on ( vec{alpha} ) D. ( vec{E} ) is uniform and both its magnitude and direction depend on ( vec{alpha} ) |
12 |

1564 | When the velocity of a relativistic charged particle increases, it’s specific charge A . Decreases B. increases c. Remains same D. First decreases then increases |
12 |

1565 | The electric potential at any point inside the first shell is: ( mathbf{A} cdot 18 times 10^{4} V ) B. ( 9 times 10^{4} V ) c. ( 4.5 times 10^{4} V ) D . ( 1.8 times 10^{4} V ) |
12 |

1566 | Graph between electric potential and the x-coordinate is given and the electric field is along the x-axis.Then find total charge in various cubes placed with one edge along positive ( x ) axis |
12 |

1567 | Why is electrical wiring usually covered with a layer of plastic? A. To make it strong B. To help electricity flow in it c. To make it safe D. To make it beautiful |
12 |

1568 | The property between two charged ebonite rods is : fur A. attraction B. repulsion ( c cdot ) both D. none |
12 |

1569 | Two identical charged spheres are suspended by strings of equa |