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

#### List of magnetism and matter Questions

Question No | Questions | Class |
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1 | Let the magnetic field on the earth be modelled by that of a point magnetic dipole at the centre of the earth. The angle of dip at a point the geographical equator This question has multiple correct options A. is always zero B. can be zero at specific points c. can be positive or negative D. is bounded | 12 |

2 | If a diamagetic solution is poured into a U-tube and one arm of this U-tube is placed between the poles of a strong magnet, with the meniscus in line with the field, then the level of solution will : A . rise B. fall c. oscillate slowly D. remain as such | 12 |

3 | The relative magnetic permeability of a magnetic material is 800 . Identify the nature of magnetic material and state its own properties. | 12 |

4 | Mention the desired properties of magnetic materials used in making electromagnets. | 12 |

5 | A bar magnet is placed with its North pole pointing North. Neutral point is at a distance ‘d’ from the center of magnet. The net magnetic induction at the same distance on the axial line of the magnet. A ( cdot 2 B_{H} ) в. ( 3 B_{H} ) ( c . B_{H} ) D. ( 7 B ) н | 12 |

6 | Magnetic field lines: A. starts from north pole B. starts from south pole c. starts from current-carrying wires D. are closed loops | 12 |

7 | A bar magnet of magnetic moment ( 1.2 A m^{2} ) is placed in the magnetic meridian with its south pole pointing the north. If a neutral point is found at a distance of ( 20 mathrm{cm} ) from the centre of the magnet, the value of the horizontal component of the earth’s magnetic field is ( mathbf{A} cdot 3 times 10^{-5} T ) B ( .3 times 10^{-4} T ) ( mathbf{c} cdot 3 times 10^{3} T ) D. ( 3 times 10^{-3} T ) | 12 |

8 | Dynamo is a device that converts. A. Alternating current into direct current B. Electrical energy into mechanical energy C. Mechanical energy into electrical energy D. Heat energy into electrical energy | 12 |

9 | At two points separated by a distance of ( 3 mathrm{cm}, ) the magnetic field strength due to a short magnet on its axial line are in the ratio 512:125. Then the distance of magnet from the first point is: A. ( 8 mathrm{cm} ) B. ( 11 mathrm{cm} ) ( c cdot 4 c m ) D. 5cm | 12 |

10 | The susceptibility of a paramagnetic substance was found for different temperatures and a graph of ( chi ) against ( frac{1}{T} ) was plotted. From the graph, it was found that what ( chi=0.5, frac{1}{T}=5 times ) ( 10^{-3} / K . ) What is the curie constant for the substance? A. ( 50 k ) B. 75 K c. ( 100 mathrm{k} ) D. 125 K | 12 |

11 | The temperature, at which a ferromagnetic material entirely loses its magnetic properties, is referred as A. non magnetic point B. curie point c. van revolt point D. none | 12 |

12 | Which of the following figures represents the magnetic lines of force due to an isolated north pole? ( A ) B. ( c ) D. | 12 |

13 | What do you mean by angle of inclination and horizontal component of magnetic field. Establish relation between them. | 12 |

14 | The use of Helmholtz coils is to produce A. uniform magnetic field B. non-uniform magnetic field c. varying magnetic field D. zero magnetic field | 12 |

15 | ( chi_{1} ) and ( chi_{2} ) are susceptibility of ( a ) paramagnetic material at temperatures ( T_{1} K ) and ( T_{2} K ) respectively, then A ( cdot x_{1}=x_{2} ) в. ( chi_{1} T_{1}=chi_{2} T_{2} ) c. ( chi_{1} T_{2}=chi_{2} T_{1} ) D cdot ( chi_{1} sqrt{T_{1}}=chi_{2} sqrt{T_{2}} ) | 12 |

16 | Mark correct option or options: A. Electric field and magnetic field are basically independent B. Electric field and magnetic field are two aspect of the electromagnetic field C. Electric field and magnetic field may be produced by charge in rest D. Both ( (a) ) and ( (c) ) are correct | 12 |

17 | Depending on the magnetic property the materials are classified in to diamagnetic, paramagnetic and ferro magnetic. The behaviour of magnetic field lines near a magnetic substance is shown in the figure. Which material corresponds to the figure. | 12 |

18 | The distance between two magnetic poles is doubled and their pole-strength is also doubled. The force between them A. Increases to four times B. Decreases by half c. Remains unchanged D. Increases to two times | 12 |

19 | Hysteresis loops for two magnetic materials ( A ) and ( B ) are given below: These materials are used to make magnets for electric generators, transformer core and electromagnet core. Then it is proper to use: A. A for electric generators and transformers B. A for electromagnets and B for electric generators c. A for transformer and B for electric generators D. B for electromagnets and transformers | 12 |

20 | At the magnetic poles of magnet, its attractive power is minimum A. True B. False | 12 |

21 | Write two properties of magnetic lines of force. | 12 |

22 | A loop of area ( 1 mathrm{m}^{2} ) is placed in a magnetic field ( B=2 T, ) such that plane of the loop is parallel to the magnetic field. If the loop is rotated by 180 , the amount of net charger passing through any point of loop, if its resistance is ( 10 Omega ) is then A. ( 0.4 mathrm{c} ) B. ( 0.2 mathrm{c} ) c. ( 0.8 mathrm{c} ) D. o c | 12 |

23 | Which of the following instruments is used to measure magnetic field? A. Thermometer B. Pyrometer c. Hygrometer D. Flux meter | 12 |

24 | Two parallel conductors are placed at right angles to metre scale, at the 2 cm and ( 6 mathrm{cm} ) marks, as shown. They carry currents of ( 1 A ) and ( 3 A ) respectively as shown in fig. They will produce zero magnetic field at the A. Zero mark B. ( 10 mathrm{cm} ) mark c. ( 3 c m ) mark D. ( 6 mathrm{cm} ) mark | 12 |

25 | A student uses a magnetic compass to perform a laboratory experiment in the Northern Hemisphere. She then carries the same magnetic compass with her to the Southern Hemisphere, taking care not to damage the compass in any way. When she reaches her destination at the equivalent latitude and longitude in the Southern Hemisphere, she prepares to perform the same laboratory experiment. The student looks at the compass before performing the experiment to see if the compass needle has changed. How has the compass changed? A. The compass needle points ( 90^{circ} ) to the left of the expected direction B. The compass needle points ( 90^{circ} ) to the right of the expected direction c. The compass needle slowly rotates in a counter clockwise direction D. The compass needle slowly rotates in a clockwis tion as been no he co | 12 |

26 | In the above figure, tube A contains copper fillings and tube B contains aluminum fillings. If a strong magnet is brought close to the two tubes as shown in the figure, then (A) Centre of gravity of the tube A move towards the right (B) Centre of gravity of tube B move towards the right A. Only A is true B. Only B is true c. Both ( A ) and ( B ) are true D. Neither A nor B is true | 12 |

27 | Force between two identical bar magnets whose centres are ( r ) metre apart is ( 4.8 N ), when their axes are in the same line. If separation is increased to ( 2 r, ) the force between them is reduced to. This question has multiple correct options | 12 |

28 | 28. A magnetic needle of magnetic moment 60 Am is directed towards the geographical north at a place. It experiences a torque of 1.2 x 10 Nm. If the earth’s horizontal component of that place is 40 u Wb m then the angle of decimation at that plane will be (a) 30° (b) 45° (c) 60° (d) 90° | 12 |

29 | Find the magnetic field at P due to the arrangement shown A ( cdot frac{mu_{0} i}{sqrt{2} pi d}left(1-frac{1}{sqrt{2}}right) & ) B. ( frac{2 mu_{0} i}{sqrt{2} pi d} ) c. ( frac{mu_{0} i}{sqrt{2} pi d} ) D. ( frac{mu_{0} i}{sqrt{2} pi d}left(1+frac{1}{sqrt{2}}right) ) | 12 |

30 | (AUDOD 00) (U) 10 8. A magnetic needle is kept in a non-uniform magnetic field. It experiences (a) a force but not torque (b) a force and a torque (c) neither a force, nor a torque (d) a torque but not force (AIEEE 2005) | 12 |

31 | The upper limit temperature of a super conductor is ( mathbf{A} cdot 115 mathrm{K} ) B. 120 K c. ( 125 mathrm{k} ) D. ( 130 mathrm{K} ) | 12 |

32 | The ratio of magnetic fields due to a bar magnet at the two axial points ( P_{1} ) and ( P_{2} ) which are separated from each other by ( 10 mathrm{cm} ) is ( 25: 2 . ) Point ( P_{1} ) is situated at 10cm from the centre of the magnet.Points ( P_{1} ) and ( P_{2} ) are on the same side of magnet and distance of ( boldsymbol{P}_{2} ) from the centre is greater than distance of ( P_{1} ) from the centre of magnet,then magnetic length is A. ( 5 mathrm{cm} ) B. ( 10 mathrm{cm} ) c. ( 15 mathrm{cm} ) D. ( 20 mathrm{cm} ) | 12 |

33 | If a magnet is suspended at angle ( 30^{circ} ) to the magnet meridian, the dip of needle makes angle of ( 45^{circ} ) with the horizontal, the real dip is ( ^{A} cdot tan ^{-1}left(frac{sqrt{3}}{2}right) ) B ( cdot tan ^{-1}(sqrt{3}) ) ( ^{mathrm{c}} tan ^{-1}(sqrt{frac{3}{2}}) ) D ( cdot tan ^{-1}left(frac{2}{sqrt{3}}right) ) | 12 |

34 | The horizontal component of the earth’s magnetic field at a place is ( B ) and angle of dip is ( 60^{circ} . ) What is the value of vertical component of earth’s magnetic field at equator? | 12 |

35 | Choose the correct alternative, in relation to properties of magnetic lines of force. A. Magnetic lines of force start from south pole and end on north pole B. Magnetic lines of force intersect each other at the poles c. Magnetic lines of force are far from each other where the field is strong D. Tangent at any point on the magnetic lines of force gives the direction of the magnetic field at that point. | 12 |

36 | If a dip circle is placed in a vertical plane at an angle of ( 30^{circ} ) to the magnetic meridian, the dip needle makes an angle of ( 45^{circ} ) with the horizontal. The real dip at that place is? A ( cdot tan ^{-1}(sqrt{3} / 2) ) B. ( tan ^{-1}(sqrt{3}) ) C ( cdot tan ^{-1}(sqrt{3} / sqrt{2}) ) D cdot ( tan ^{-1}(2 / sqrt{3}) ) | 12 |

37 | The earth is considered as a short magnet with its centre coinciding with the geometric centre of earth. The angle of dip ( phi ) related to the magnetic latitude ( alpha lambda ) as ( ^{mathbf{A}} cdot tan phi=frac{1}{2 tan alpha} ) B. ( tan lambda=tan phi ) c. ( tan lambda=2 tan phi ) D. ( tan phi=2 tan lambda ) | 12 |

38 | The strength of the Earth’s magnetic field is? A. Constant everywhere B. Zero everywhere c. Having very high value D. Varying from place to place on the Earth’s surfact | 12 |

39 | The vertical component of earth’s magnetic field at a place is ( sqrt{3} ) times the horizontal component the value of angle of dip at this place is A ( .30^{circ} ) В ( cdot 45^{circ} ) ( c cdot 60^{0} ) D. ( 90^{circ} ) | 12 |

40 | At a place, the horizontal and vertical components of earth’s magnetic field are equal. What is the angle of dip at that place? A . 45 B. 55 ( c cdot 65 ) D. 76 | 12 |

41 | Relative permittivity and permeability of a material are ( epsilon_{mathrm{r}} ) and ( mu_{mathrm{r}}, ) respectively. Which of the following values of these quantifies are allowed for a diamagnetic material? A ( cdot epsilon_{mathrm{r}}=0.5, mu_{mathrm{r}}=0.5 ) B . ( epsilon_{mathrm{r}}=1.5, mu_{mathrm{r}}=1.5 ) ( mathbf{c} cdot epsilon_{mathrm{r}}=0.5, mu_{mathrm{r}}=1.5 ) D. ( epsilon_{mathrm{r}}=1.5, mu_{mathrm{r}}=0.5 ) | 12 |

42 | Magnetic field can be defined as the: A. space surrounding the magnet in which magnetic force acts B. space surrounding the magnet in which electric force acts C. space surrounding the magnet in which no force acts D. none | 12 |

43 | A current carrying loop is placed in a uniform magnetic field pointing in negative z direction. Branch PQRS is a tree quarter circle, while branch PS is straight. If force on branch PS is ( mathrm{F} ), force on branch PQR is: ( A cdot sqrt{2} F ) в. ( frac{F}{sqrt{2}} ) с. ( frac{pi F}{sqrt{2}} ) ( mathbf{D} cdot sqrt{2} pi F ) | 12 |

44 | The magnetic susceptibilty for diamagnetic materials is A. small and negative B. small and positive c. large and positive D. large and negative | 12 |

45 | The equatorial magnetic field of earth is 0.4G. Then its dipole moment on equator is A ( cdot 1.05 times 10^{23} mathrm{Am}^{2} ) В. ( 2.05 times 10^{23} mathrm{Am}^{2} ) c. ( 1.05 times 10^{21} A m^{2} ) D. ( 2.05 times 10^{21} mathrm{Am}^{2} ) | 12 |

46 | Consider the Earth as a short magnet with its centre coinciding with the centre of the Earth and dipole moment is ( M . ) The angle of dip ( delta ) is related to latitude ( lambda ) as : ( A cdot tan delta=tan lambda ) B. ( tan delta=2 tan lambda ) ( c cdot tan delta=frac{tan lambda}{2} ) D. ( tan delta=cot lambda ) | 12 |

47 | The permanent magnetic moment of the atoms of a material is not zero. The material : A. must be paramagnetic B. must be diamagnetic c. must be ferromagnetic D. may be paramagnetic | 12 |

48 | What is the phenomenon shown by ferromagnetic substances whereby the magnetic flux through the medium on magnetising field as well as previous state of the substance? A. Irradiation B. Hysteresis c. Inversion D. Magnetostriction | 12 |

49 | Out of given paramagnetic substance (Calcium, Chromium, Oxygen and Tungsten) which substance has maximum susceptibility? A. Calcium B. Chromium c. oxygen D. Tungsten | 12 |

50 | A susceptibility of a certain magnetic material is ( 400 . ) What is the class of the magnetic material? A. Diamagnetic B. Paramagnetic c. Ferromagnetic D. Ferroelectric | 12 |

51 | Electromagnets are made of soft iron because soft iron has A. high susceptibility and low retentivity B. low susceptibility and high retentivitty c. low susceptibility and low retentivity D. high susceptibility and high retentivity | 12 |

52 | The variation of magnitude field ( (B) ) due to circular coil as the distance ( boldsymbol{X} ) varies is shown in the graph. Which of the following is false? A. Point ( A ) and ( A^{prime} ) are known as point of zero curvature. B. ( B ) varies linearly with ( X ) at point ( A ) and ( A^{prime} ) ( frac{d B}{d t}=0 ) at point ( A ) and ( A^{prime} ) ( frac{d^{2} B}{d t^{2}}=0 ) at point ( A ) and ( A^{prime} ) | 12 |

53 | A long horizontal metallic rod with length along the east-west direction is falling under gravity. The potentiol difference between its two ends will : A. be zero B. be constant c. increase with time D. decrease with time | 12 |

54 | At a place the angle of dip is ( 30^{circ} ). If the horizontal component of the earth’s magnetic field is ( H, ) then the total field intensity will be given by A ( cdot frac{H}{2} ) в. ( frac{2 H}{sqrt{3}} ) c. ( frac{H}{sqrt{2}} ) D. ( H sqrt{2} ) | 12 |

55 | The magnet is strongest near the A. Poles of the magnet B. Ends of the magnet C. Centre of the magnet D. One quarter point from the poles of the magnet | 12 |

56 | Which of the following statement related to hysteresis loop is incorrect? A. The curve of B against H for a ferromagnetic material is called hysteresis loop B. The area of B-H curve is a measure of power dissipated per cycle per unit area of the specimen C. Coercitivity is a measure of the magnetic field required to destroy the residual magnetism of ferromagnetic material D. The retentivity of a specimen is the measure of magnetic field remaining in the specimen when the magnetising field is removed | 12 |

57 | A current of ( 10 A ) is flowing in a equilateral triangle of side length ( ell= ) ( 1 m ) as shown in figure. The magnetic field at centre of triangle is : A ( cdot 8 times 10^{-6} T ) В. ( 9 times 10^{-5} T ) c. ( 9 times 10^{-6} T ) D. ( 10^{-5} T ) | 12 |

58 | Assertion: The magnetic field lines of the earth resemble that of a magnetic dipole located at the centre of the earth. Reason: The axis of the dipole coincide with the axis of rotation of the earth. A. If both assertion and reason are true and reason is the correct explanation of assertion. B. If both assertion and reason are true and reason is not the correct explanation of assertion. c. If assertion is true but reason is false D. If both assertion and reason are false | 12 |

59 | At a certain location in Africa, a compass points ( 12^{circ} ) west of the geographic north. The north tip of the magnetic needle of a dip circle placed in the plane of magnetic meridian points ( 60^{circ} ) above the horizontal. The horizontal component of the Earth’s field is measured to be ( 0.16 G . ) Specify the direction and magnitude of the Earth’s field at the location. A ( cdot 32^{circ} ) west of geographic meridian and ( 3.2 times 10^{-4} T ) B . ( 12^{circ} ) west of geographic meridian and ( 0.32 times 10^{-4} mathrm{T} ) C. ( 12^{circ} ) east of geographic meridian and ( 0.32 times 10^{-4} mathrm{T} ) D. ( 32^{circ} ) east of geographic meridian and ( 3.2 times 10^{-4} T ) | 12 |

60 | (a) Why does a paramagnetic sample display greater magnetisation (for the same magnetising field) when cooled? (b) Why is diamagnetism, in contrast, almost independent of temperature? (c) If a toroid uses bismuth for its core, will the field in the core be (slightly) greater or (slightly) less than when the core is empty? (d) Is the permeability of a ferromagnetic material independent of the magnetic field? If not, is it more for lower or higher fields? (e) Magnetic field lines are always nearly normal to the surface of a ferromagnet at every point. (This fact is analogous to the static electric field lines being normal to the surface of a conductor at every point.) Why? (f) Would the maximum possible magnetisation of a paramagnetic sample be of the same order of magnitude as the magnetisation of a ferromagnet? | 12 |

61 | toppr Q Type your question. uniform magnetic field ( B ) with constant velocity ( boldsymbol{v} ) at ( t=0 . ) The longest side of the frame is perpendicular to the direction of velocity If i is the instantaneous current through the frame then choose the alternative showing the correct variation of i with time ( A ) ( (mathrm{A}) ) в. ( (mathrm{B}) ) ( c ) ( (mathrm{C}) ) ( D ) ( (mathrm{D}) ) | 12 |

62 | According to Curie’s law, the magnetic susceptibility of a substance at an absolute temperature T is proportional to – A. ( 1 / T ) в. ( T ) c. ( 1 / T^{2} ) D. ( T^{2} ) | 12 |

63 | Magnetic lines of force always cross each other. Is the given statement true or false? Justify. | 12 |

64 | .P A uniform but time-varying magnetic field B(1) exists in a circular region of radius a and is directed into the plane of the paper, as shown. The magnitude of the induced electric field at point P at a distance r from the centre of x x Bt) x 2 . the circular region (a) is zero x x x x x (b) decreases as 1/r (c) increases as r (d) decreases as 1/r? | 12 |

65 | A ship is travelling due east according to mariner’s compass. If the declination at that place is ( 20^{circ} ) east, the actual direction of its motion is A ( cdot 40^{circ} ) south of east B. ( 20^{circ} ) south of east C ( cdot 5^{circ} ) south of east D. ( 20^{circ} ) north of east | 12 |

66 | At a certain place, the angle of dip ( 30^{circ} ) and the horizontal component of earth’s magnetic field is 0.50 oerested.The earth’s total magnetic field (in oerested) is A. ( sqrt{3} ) B. c. ( frac{1}{sqrt{3}} ) D. ( frac{1}{2} ) | 12 |

67 | Two equal poles repel each other with a force of ( 10^{-3} ) N. When placed 2 cm apart in air, the pole strength of each is (in amp- ( mathrm{m}) ) A . ( 4 pi ) B. 2 ( c cdot 4 ) D. 2pi | 12 |

68 | Assertion The net magnetic force on a current loop in a uniform magnetic field is zero but torque may or may not be zero Reason Torque on a current carrying coil in a magnetic field is given by ( bar{tau}= ) ( boldsymbol{n} boldsymbol{I}(overline{boldsymbol{A}} boldsymbol{X} overline{boldsymbol{B}}) ) 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 |

69 | The angle of dip at the location in southern India is about ( 18^{circ} . ) Would you expect a greater or a smaller dip angle in Britain (Closer to the north pole.) | 12 |

70 | Of dia, para and ferromagnetism, the universal property of all substance is A. diamagnetism B. paramagnetism c. ferromagnetism D. all of the above | 12 |

71 | A small magnet is suspended freely by a vertical string. The horizontal and vertical components of Earth’s field is ( 20 mu T ) and ( 30 mu T ) respectively. Find the angle from horizontal at which magnet will stay in equilibrium. A ( cdot tan ^{-1}left(frac{3}{2}right) ) B ( cdot tan ^{-1}left(frac{2}{3}right) ) ( ^{c} cdot sin ^{-1}left(frac{2}{3}right) ) D. ( cos ^{-1}left(frac{2}{3}right) ) | 12 |

72 | The dimensions of the ratio of magnetic flux ( (phi) ) and permeability ( (mu) ) are? ( mathbf{A} cdotleft[M^{0} L^{1} T^{0} A^{1}right] ) B. ( left[M^{0} L^{-3} T^{0} A^{1}right] ) c. ( left[M^{0} L^{1} T^{1} A^{-1}right] ) D・ ( left[M^{0} L^{2} T^{0} A^{1}right] ) | 12 |

73 | The B-H curve (i) and (ii) shown in fig., associated with A. (i) diamagnetic and (ii) paramagnetic substance B. (i) paramagnetic and (ii) ferromagnetic substance C. (i) soft iron and (ii) steel respectively D. (i) steel and (ii) soft iron respectively | 12 |

74 | Magnetic lines of force A. are mere directions B. have no physical reality C. can be used to indicate the direction of the magnetic field at point D. all the above are correct | 12 |

75 | A body at rest starts from a point at a distance ( r(>R) ) from the center of the earth. If ( mathrm{M} ) and ( mathrm{R} ) stand for the mass and the radius of earth respectively, then the speed of the body when it reaches the Earth surface is ( ^{mathrm{A}} cdot sqrt{frac{2 G M}{R}} ) в. ( sqrt{frac{2 G M}{R-r}} ) c. ( sqrt{frac{2 G M(r-R)}{R r}} ) D. zero | 12 |

76 | Explain ferromagnetism on the basis of domain theory? | 12 |

77 | Two isolated point poles of strength ( 30 A m ) and ( 60 A m ) are placed at a distance of ( 0.3 m . ) The force of repulsion is: A ( cdot 2 times 10^{-3} N ) B . ( 2 times 10^{-4} N ) c. ( 2 times 10^{5} N ) D. ( 2 times 10^{-5} N ) | 12 |

78 | The distance between two magnetic poles is doubled and their pole-strength is also doubled. The force between them A. Increases to three times B. Decreases by half c. Remains unchanged D. Increases to two times | 12 |

79 | Relative permittivity and permeability of a material are ( varepsilon_{r} ) and ( mu_{r} ) respectively. The values of these quantities allowed for a diamagnetic material are ( mathbf{A} cdot varepsilon_{r}=0.5, mu_{r}=1.5 ) ( mathbf{B} cdot varepsilon_{r}=1.5, mu_{r}=0.5 ) ( mathbf{c} cdot varepsilon_{r}=0.5, mu_{r}=0.5 ) ( mathbf{D} cdot varepsilon_{r}=1.5, mu_{r}=1.5 ) | 12 |

80 | Derive an expression for the intensity of magnetic field on broad side on position due to a bar magnet. | 12 |

81 | Conductivity of metal decreases with temperature while conductivity of electrolytic conductors increases with temperature. Why? | 12 |

82 | allel 39. A current carrying coil is placed with its axis perpendicula to N-S direction. Let horizontal component of earth magnetic field be H, and magnetic field inside the lo is H. If a magnet is suspended inside the loop, it makes angle with H. Then 0 = ( H ) (a) tan Its bout I be (b) tan-1 H CA (c) cosec-1 ace ce, (d) cott H, Но ) | 12 |

83 | The given figure represents a material which is A. Paramagnetic B. Diamagnetic c. Ferromagnetic D. Ferrimagnetic | 12 |

84 | The plane of a dip circle is set in the geographic meridian. Then the apparent dip is ( left(delta_{1} text { is the actual dip and } delta_{2} ) is the right. declination): A ( cdot theta=tan ^{-1}left(frac{tan delta_{1}}{tan delta_{2}}right) ) B . ( theta=tan ^{-1}left(tan delta_{1} cos delta_{2}right) ) c. ( theta=tan ^{-1}left(frac{tan delta_{2}}{cos delta_{1}}right) ) D. ( theta=tan ^{-1}left[tan delta_{1} cos delta_{2}right] ) | 12 |

85 | What is the direction of magnetic field at the centre of a coil carrying clockwise current? A. No direction B. normal to the axis of coil inwards c. Along the axis of coil inwards. D. Along the axis of coil outwards | 12 |

86 | The purpose of soft iron cylinder between the pole pieces of the horse- shoe magnet in a moving coil galvanometer is A. to increase the magnetic induction in the polar ( operatorname{gap} ) B. to evenly distribute the magnetic lines of force C. to provide a radial magnetic field D. to reduce the magnetic flux leakage in the polar ( operatorname{gap} ) | 12 |

87 | Two short bar magnets with magnetic moments 400 ab-amp ( c m^{2} ) and 800 ab amp ( c m^{2} ) are placed with their axis in the same straight line with similar poles facing each other and with their centres at ( 20 mathrm{cm} ) from each other. Find the force of repulsion. | 12 |

88 | The figure shows the various positions (labelled by subscripts) of small magnetised needles ( P ) and ( Q ). The arrows show the direction of their magnetic movement.configuration corresponds to the lowest potential energy among all the configurations shown A . ( P Q_{3} ) в. ( P Q_{4} ) ( c cdot P Q_{5} ) D. ( P Q_{6} ) | 12 |

89 | Angle of dip is ( 90^{circ} ) at: A. Equator B. Middle point c. Poles D. None of these | 12 |

90 | A paramagnetic substance when placed in an externally applied non-uniform magnetic field tends to A. increase the applied field B. decrease the applied field c. vary the applied field D. change the applied field | 12 |

91 | If a diamagnetic substance is brought near the north or the south pole of a bar magnet, it is A. attracted by both the poles B. repelled by both the poles c. repelled by the north pole and attracted by the south pole D. attracted by the north pole and repelled by the south pole | 12 |

92 | Show diagramatically the behavior of magnetic field lines in the presence of (i) paramagnetic and (ii) diamagnetic substances. How does one explain this distinguishing feature. | 12 |

93 | The horizontal component of earth’s magnetic field at a place is ( frac{1}{sqrt{3}} ) times the vertical component. Determine the angle of dip at that place. | 12 |

94 | Two magnets of equal mass are joined at right angles to each other as shown Magnet 1 has a magnetic moment 3 times that of magnet 2. This arrangement is pivoted so that it is free to rotate in the horizontal plane. In equilibrium what angle will the magnet 1 subtend with the magnetic meridian A ( cdot tan ^{-1}left(frac{1}{2}right) ) B. ( tan ^{-1}left(frac{1}{3}right) ) ( c cdot tan ^{-1}(1) ) D. ( 0^{circ} ) | 12 |

95 | Critical temperature can be defined as the A. Temperature at which there is no motion between the molecules B. Temperature at which a gas is converted into its liquid state C. Temperature at which volume of a gas becomes zero D. Temperature above which a gas cannot be liquefied no matter however high the pressure may be | 12 |

96 | 48. The variation of magnetic susceptibility (X) with absolute temperature T for a ferromagnetic material is X4 XA (b) -TOLT S of T آاها 49 Thor 1/Troph for an alloy of | 12 |

97 | The armature of de motor has ( 20 Omega ) resistance .It draws current of 1.5 ampere when run by 220 volts dc supply. The value of back e.m.f. induced in it will be ( A cdot 190 V ) B. 150 V c. ( 170 v ) D. ( 120 mathrm{V} ) | 12 |

98 | The strength of a magnet is in the middle and A. weakest, weakest B. strongest, strongest c. weakest, strongest D. strongest, weakest | 12 |

99 | The force required just to move a body up an inclined plane is double the force required just to prevent the body sliding down. If the coefficient of a fraction is ( 0.25, ) the angle of inclination of the plane is A ( cdot 36.8 ) B . 45 ( c .30 ) D. ( 42.6^{circ} ) | 12 |

100 | Identify the contour lines along which the dip measured at the Earth’s surface is equal in magnitude. A. Aclinic lines B. Isoclinic lines c. Isogonic lines D. Agonic lines | 12 |

101 | 70. A bar magnet has coercivity 4 10′ Am. It is desired to demagnetise it by inserting it inside a solenoid 12 cm long and having 60 turns. The current that should be sent through the solenoid is (a) 2 A (b) 4A (c) 6 A (d) 8A | 12 |

102 | Two identical magnetic dipoles are placed, as shown separated by distance d. The magnetic field, mid way between the dipoles, is : ( A ) [ frac{mu_{0} M sqrt{2}}{4 pi d^{3}} ] B. [ frac{mu_{0} M sqrt{5}}{4 pi d^{3}} ] ( c ) [ frac{2 mu_{0} M sqrt{5}}{pi d^{3}} ] D. none of these | 12 |

103 | Write two examples of ferromagnetic substance. | 12 |

104 | Which of the following statements is wrong? Magnetic lines of force A. Form closed circuits B. Never intersect c. Are densest near the poles D. None of the above | 12 |

105 | The magnetic field of the earth can be modelled by that of a point dipole placed at the centre of the earth. The dipole axis makes an angle of ( 11.3^{circ} ) with the axis of the earth. At Mumbai, declination is nearly zero. Then A. the declination varies between ( 11.3^{circ} mathrm{W} ) to ( 11.3^{circ} mathrm{E} ) B. the least declination is ( 0^{circ} ) C. the plane defined by dipole axis and Earth axis passes through Greenwich D. declination averaged over Earth must be always negative | 12 |

106 | 16. The resistance in the following circuit is increased at a particular instant. At this instant the value of resistance is 10 12. The current in the circuit will be now 10 mH W 5v (a) i = 0.5 A (c) i 0.5 A (d) i = 0 | 12 |

107 | An aeroplane is flying from city ( A ) to ( B ) along path 1. The path 1 is a circular arc whose centre coincides with the centre of the earth. Another aeroplane is flying along path 2 from ( A ) to ( B ). The path 2 is circular arc whose centre is at ( mathrm{C} ). O is the centre of the earth. Then A. The distance travelled by ( 1^{s t} ) aeroplane is greater than that of ( 2^{n d} ) aeroplane B. The distance travelled by ( 1^{text {st}} ) aeroplane is less than that of ( 2^{n d} ) aeroplane c. The displacement of both aeroplane is different D. None of these | 12 |

108 | How will you quantize the relative permeability of a paramagnetic substance ? A. Much more than one B. Slightly more than one c. Less than one but greater than zero D. zero | 12 |

109 | At a certain location in Africa, a compass points ( 12^{circ} ) west of the geographic north. The north tip of the magnetic needle of a dip circle placed in the plane of magnetic meridian points ( 60^{circ} ) above the horizontal. The horizontal component of the earth’s field is measured to be 0.16 G. Specify the direction and magnitude of the earth’s field at the location. | 12 |

110 | State whether true or false. A magnetic field is a region around a magnet where magnetic lines of force act A. True B. False | 12 |

111 | Assertion The magnetic poles of earth do not coincide with the geographic poles. Reason The discrepancy between the orientation of a compass and true north-south direction is known as magnetic declination. 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 |

112 | Rajkumar said to you that the magnetic field lines are open and they start at north pole of bar magnet and end at south pole. What questions do you ask Rajkumar to correct him by sayingfield lines are closed? | 12 |

113 | A ferromagnetic material is heated above its curie temperature. Which one of a correct statement? A. Ferromagneitc domains are perfectly arranged B. Ferromagnetic domains become random c. Ferromagnetic domains are not influenced D. Ferromagnetic material changes into diamagnetic material | 12 |

114 | A telephone cable at a place has four long straight horizontal wires carrying a current of ( 1.0 mathrm{A} ) in the same direction east to west. The earth’s magnetic field at the place is ( 0.39 mathrm{G}, ) and the angle of dip is ( 35^{circ} . ) The magnetic declination is nearly zero. What are the resultant magnetic fields at points 4.0 ( mathrm{cm} ) below the cable? | 12 |

115 | Explain the term hysteresis. | 12 |

116 | Three identical bars ( A, B ) and ( C ) are made of different magnetic materials. When kept in a uniform magnetic field, the field lines around them look as given in the figure. Make the correspondence of these bars with their material being diamagnetic (D), ferromagnetic (F) and paramagnetic (P) A. ( A leftrightarrow F, B leftrightarrow D, C leftrightarrow P ) в. ( A leftrightarrow D, B leftrightarrow P, C leftrightarrow F ) c. ( A leftrightarrow F, B leftrightarrow P, C leftrightarrow D ) D. ( A leftrightarrow P, B leftrightarrow F, C leftrightarrow D ) | 12 |

117 | Which metal is suitable to use to make a permanent magnet? A. Aluminium B. Brass c. Iron D. stee | 12 |

118 | If the liquid in a U-tube rises to high level in the limb placed between poles of an electromagnet, then the liquid is: A. non-magnetic B. diamagnetic c. paramagnetic D. ferromagnetic | 12 |

119 | Q Type your question temperature (T) is represented then by ( A ) ( B ) ( c ) ( D ) | 12 |

120 | 62. A coil in the shape of an equilateral triangle of side 0.02 m is suspended from its vertex such that it is hanging in a vertical plane between the pole pieces of permanent magnet producing a uniform field of 5 x 10-2T. If a current of 0.1 A is passed through the coil, what is the couple acting? (a) 5/3×10-7 N-m (b) 513×10-10 N-m (c) 2×10-7 N-m (d) None of these | 12 |

121 | Iron is ferromagnetic: A. at all temperatures B. at NTP only C . above ( 770^{circ} mathrm{C} ) D. below ( 770^{circ} mathrm{C} ) | 12 |

122 | 14. Two short bar magnets of length 1 cm each have magnetic moments 1.20 Am and 1.00 Am², respectively. They are placed on a horizontal table parallel to each other with their N poles pointing towards the south. They have a common magnetic equator and are separated by a distance of 20.0 cm. The value of the resultant horizontal magnetic induction at the mid-point 0 of the line joining their centres is close to (horizontal component of earth’s magnetic induction is 3.6 x 10- Wb/m?) (a) 2.56 x 104 Wb/m2 (b) 3.50 x 10+Wb/m² (c) 5.80 x 104 Wb/m² (d) 3.60 x 10-Wb/m² (JEE Main 2013) | 12 |

123 | The vertical plane which passes through the magnetic axis of a freely suspended magnetic at rest is called A. Magnetic meridian B. Geographical meridian c. North meridian D. South meridian | 12 |

124 | Assertion Basic difference between an electric line and magnetic line of force is that former is discontinuous and the later is continuous or endless. Reason No electric lines of force exist inside a charged body but magnetic lines do exist inside a magnet. A. Both Assertion and Reason are correct and Reason is the correct explanation of Assertion B. Both Assertion and Reason are correct, but Reason is not the correct explanation of Assertion C. Assertion is correct but Reason is incorrect. D. Assertion is incorrect but Reason is correct. | 12 |

125 | (a) An iron ring of relative permeability ( mu_{r} ) has windings of insulated copper wire of ( n ) turns per metre. When the current in the windings is ( I ), find the expression for the magnetic field in the ring. (b) The susceptibility of a magnetic material is ( 0.9853 . ) Identify the type of magnetic material. Draw the modification of the field pattern on keeping a piece of this material in a uniform magnetic field. | 12 |

126 | Curie-Weiss law is obeyed by iron. A. At curie temperature only B. At all temperatures C . Below curie temperature D. Above curie temperature | 12 |

127 | Which of the following materials which lack permanent magnetic dipoles? A. diamagnetic B. ferromagnetic c. semimagnetic D. none of the above | 12 |

128 | The hysteresis cycle for the material of permanent magnet is A. Short and wide B. Tall and narrow c. Tall and wide D. short and narrow | 12 |

129 | In the hysteresis cycle, the value of ( boldsymbol{H} ) needed to make the intensity of magnetism zero is called A. Retentivity B. Coercive force c. Lorentz force D. None of the above | 12 |

130 | Define Curie temperature in magnetism. | 12 |

131 | Bell laboratory has developed superconductor at a temperature of A. 30 K в. 40 к ( c . ) 50 ( k ) D. 60 | 12 |

132 | Draw a labelled diagram of a moving coil galvanometer and explain its working. What is the function of radial magnetic field inside the coil? | 12 |

133 | At a certain place, horizontal component is ( sqrt{3} ) times the vertical component. The angle of dip at this place is: A . в. ( pi / 3 ) c. ( pi / 6 ) D. none of these | 12 |

134 | The coercivity of a magnet is ( 3 x ) ( 10^{3} A m^{-1} . ) What current should be passed through a solenoid of length ( 10 mathrm{cm} ) and number of turns 50 that the magnet is demagnetized when inserted in it? A ( .3 A ) в. ( 6 A ) c. ( 9 A ) D. ( 12 A ) | 12 |

135 | A clinic lines on magnetic map represent the lines of A. zero declination B. equal declination c. zero dip D. equal dip | 12 |

136 | The value of angle of dip at magnetic poles of the Earth is | 12 |

137 | The current in the coil is reversed, and the coil is rotated about its vertical axis by an angle of ( 90^{circ} ) in the anticlockwise sense looking from above. Predict the direction of the needle. Take the magnetic declination at the places to be zero. | 12 |

138 | In a permanent magnet at room temperature A. magnetic moment of each molecule is zero B. the individual molecules have non-zero magnetic moment which are all perfectly aligned C . domains are partially aligned D. domains are all perfectly aligned | 12 |

139 | The force of repulsion between two similar magnetic poles each of strength ( 2 A m ) at a distance ( 2 m ) from each other in vacuum is : A ( cdot 10^{-5} N ) В. ( 10^{-7} N ) c. ( 10^{-3} N ) D. ( 2 times 10^{-7} N ) | 12 |

140 | A long straight wire of radius ( a ) carries a steady current i. The current is uniformly distributed across its cross section. The ratio of the magnetic field ( operatorname{ata} / 2 ) and ( 2 a ) is: A . ( 1 / 2 ) в. ( 1 / 4 ) ( c cdot 4 ) D. | 12 |

141 | Which of the following is minimum at the poles? A. Angle of dip B. Horizontal component of the earth’s magnetic field c. Angle of declination D. Vertical component of the earth’s magnetic field | 12 |

142 | Two magnetic monopoles are kept apart by a distance ‘d’. The magnetic force acting on each pole is ‘F’. How much percentage must the distance between the magnetic poles be changed so that the magnetic force acting on each pole be ( 4 mathrm{F} ) A . -10% B . -20% c. -40% D . -50% | 12 |

143 | The angle of inclination of the axis of the magnetic needle to the horizontal plane when suspended freely and is at rest is known as A. Angle of inclination B. Angle of variation c. Angle of declination D. None of the above | 12 |

144 | ( P ) is the centre of the square ( B_{p}=? ) Four ( boldsymbol{L} ) shaped wires, each carrying current ( boldsymbol{I} ) Find the magnetic field at point ( boldsymbol{P} ) ? A ( cdot 1 w b / m^{2} ) В. ( 0 w b / m^{2} ) ( c cdot 2 w b / m^{2} ) D. none of these | 12 |

145 | Point out the wrong statement about the magnetic properties of soft iron and steel A. Retentivity of soft iron is more than retentivity of steel B. Coercivity of soft iron is less than coercivity of steel. c. Area of B-H loop in soft iron is smaller than the area of B-H loop for steel D. Area of B-H loop in soft iron is greater than the area of B-H loop for steel | 12 |

146 | The temperature of transition from ferromagnetic property to paramagnetic property is called as: A. Transition temperature B. Critical temperature c. Curie temperature D. Triplet temperature | 12 |

147 | Magnetic field of earth is identical to magnetic field of a giant magnet held ( 20^{circ} ) west of geographic ( N-S ) at the centre of earth. At equator, horizontal component of earth is ( 0.32 G ). Vertical component can be calculated from the relation ( V=H ) tan ( delta, ) where ( delta ) is angle of dip at the place. The value of ( boldsymbol{delta}=mathbf{0}^{boldsymbol{o}} ) at equator and ( delta=90^{circ} ) at poles. What is the order of magnetic declination at a place on earth : A ( cdot 20^{circ} ) East B . ( 10^{circ} ) East c. ( 20^{circ} ) west D. ( 10^{circ} ) west | 12 |

148 | Write any three properties of magnetic lines of force. | 12 |

149 | A circular conductor of radius ( 5 mathrm{cm} ) produce magnetic field of ( 7 times 10^{-6} mathrm{T} ) The current flows through the conductor is A. 3.0 A B. 2.25 A c. 4.5 A D. 0.56 A | 12 |

150 | Consider the earth as a short magnet with the centre coinciding with the centre of the earth and dipole moment ( M ). The angle of dip ( theta ) at the place where the magnetic latitude is ( lambda ) is : A ( cdot tan ^{-1}(2 tan lambda) ) B. ( tan ^{-1}(tan lambda) ) ( c cdot tan ^{-1}(tan lambda / 2) ) D. ( tan ^{-1}(4 tan lambda) ) | 12 |

151 | Strength of earth’s magnetic field is of the order of : ( mathbf{A} cdot 10^{-4} T ) B. ( 10^{-3} T ) c. ( 10^{-5} T ) D. ( 10^{-6} T ) | 12 |

152 | A short bar magnet is placed with its south pole pointing geographic North at a place where ( B_{H}=0.4 ) gauss. The length of the magnet is ( 10 mathrm{cm} ) and pole strength is ( 16 A-m ). The distance of each null point from the centre will be A. ( 0.2 m ) on axial line B. ( 0.8 mathrm{cm} ) on axial line c. ( 0.4 mathrm{cm} ) on axial line D. ( 0.2 mathrm{cm} ) on equitorial line | 12 |

153 | The total intensity of the earth’s magnetic field at equator is 5 units. What is its value at the poles? A . 5 B. 4 ( c .3 ) D. 2 | 12 |

154 | 50. Which of the following is true? (a) Diamagnetism is temperature dependent (b) Paramagnetic is temperature dependent (c) Paramagnetic is temperature independent (d) None of these | 12 |

155 | The angles of dip at the poles and the equator respectively are : A ( cdot 30^{0}, 60^{circ} ) ( ^{0}, 66^{0} ) В. ( 90^{0}, 0^{0} ) c. ( 30^{0}, 90^{circ} ) D. ( 0^{0}, 0^{0} ) | 12 |

156 | Two magnetic monopoles are kept apart by a distance ‘d. The magnetic force acting on each pole is ‘ ( boldsymbol{F} ) “. How much percentage must the distance between the magnetic poles be changed so that the magnetic force acting on each pole be ( 4 F ) A. Decreases by ( 50 % ) B. Decreases by 20% c. Increased by ( 50 % ) D. Increased by ( 20 % ) | 12 |

157 | Properties of magnetic lines of force are: A. The imaginary lines which represent the direction of magnetic field, are known as magnetic lines of force. B. Magnetic lines of force are closed curves. C. Outside the magnet their direction is from north pole to south pole and inside the magnet these are from south to north pole. D. All | 12 |

158 | A galvanometer of number of turns 175 having ( 1 mathrm{cm}^{2} ) area, turns through ( 1^{circ} ) when a current of ( 1 m A ) is passed. Find magnetic field if torsional constant of spring is ( 10^{-6} N-m ) A ( cdot 10^{-4} T ) B. ( 10^{-3} T ) c. ( 10^{-5} T ) D. ( 10^{-2} T ) | 12 |

159 | Q Type your question ferromagnetic material can be ploted as : ( A ) B. ( c ) ( D ) | 12 |

160 | The magnetic field of the earth can be modelled by that of a point dipole placed at the centre of the earth. The dipole axis makes an angle of ( 11.3^{circ} ) with the axis of the earth. At mumbai declination is nearly zero. Then A. the declination varies between ( 11.3^{circ} ) W to ( 11.3^{circ} ) E B. the least declination is ( 0^{circ} ) c. the plane defined by dipole and the earth axis posses through greenwich D. declination average over the earth must be always negative | 12 |

161 | Alnico is used for making permanent magnets because it has A. High coercivity and high retentivity B. high coercivity and low retentivity C. low coercivity and low retentivity D. low coercivity and high retentivity | 12 |

162 | If I is the intensity of earth’s magnetic field, H its horizontal component and ( V ) the vertical component, then these are related as: ( mathbf{A} cdot I=V+H ) ( mathbf{B} cdot I=sqrt{H^{2}+V^{2}} ) ( mathbf{C} cdot I=sqrt{H^{2}-V^{2}} ) D ( cdot I=H^{2}-V^{2} ) | 12 |

163 | A bar magnet of length of ( 0.1 m ) has a pole strength of 50 Am. Calculate the magnetic field at a distance of ( 0.2 m ) from its centre on (i) its axial line and (ii) its equatorial line. | 12 |

164 | Which of the following is minimum at the equator? A. Angle of dip B. Horizontal component of earth’s magnetic field c. Angle of declination D. Intensity of the earth’s field | 12 |

165 | A line joining places of equal declination is called A . aclinical B. isoclinical c. isodynamical D. isogonal | 12 |

166 | Write the causes of energy loss and ways to reduce them in transformer (any four) | 12 |

167 | 21. The values of the apparent angles of dip in two planes at right angles to each other are 300 and 45º. Then the true value of the angle of dip at the place is (a) tan-‘1 (b) tan-12 (c) cot-‘2 (d) cot-4 | 12 |

168 | A long magnet is cut into two equal parts such that the length of each half is same as that of original magnet. If the period of original magnet is ( T, ) then the period of new magnet is : A. ( T ) в. ( T / 2 ) c. ( T / 4 ) D. ( 2 T ) | 12 |

169 | Ferrimagnetic those expected to have large magnetism but actually have small net magnetic moment e.g. magnetic ( left(boldsymbol{F} boldsymbol{e}_{3} boldsymbol{O}_{4}right), ) ferrites ( left(boldsymbol{M}^{2}+right. ) ( F e_{2} O_{4} ) ). This is because of unequal number of domains in opposite direction. | 12 |

170 | Assertion The ferromagnetic substance do not obey Curie’s law. Reason At Curie point a ferromagnetic substance start behaving as a paramagnetic substance. 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 |

171 | The variation of magnetic susceptibility with the temperature of a ferromagnetic material can be plotted as? ( A ) в. ( c ) D. | 12 |

172 | The susceptibility of magnetic material is ( -4.2 times 10^{-6} . ) Name the type of magnetic material it represents. | 12 |

173 | Two magnetic poles one of which is three times as strong as the other exert on each other, a force equal to ( 3 times 10^{-3} ) when separated by a distance of ( 10 mathrm{cm} ). The strength of the each pole is ( mathbf{A} .5 mathrm{Am}, 15 mathrm{Am} ) В. 30 Ат, 10 Ат ( mathbf{c} .20 mathrm{Am}, 60 mathrm{Am} ) D. ( 50 A m, 150 A m ) | 12 |

174 | in the magnetic meridian of a place, the horizontal component of the earth’s magnetic field is 0.26 and the dip angle is 60 and the dip angle is 60 What is the magnetic field of the earth at this location? | 12 |

175 | In a region of uniform magnetic induction ( B=10^{-2} ) tesla, a circular coil of radius ( 30 mathrm{cm} ) and resistance ( pi^{2} ) ohm is rotated about an axis, which is perpendicular to the direction of B and which forms a diameter of coil. If the coil rotates at 200 r.p.m., the amplitude of alternating current induced in the coil is :- A ( cdot 4 pi^{2} mathrm{m} ) B. 30 mA ( c cdot 6 m ) D. 200 mA | 12 |

176 | Value of ( boldsymbol{H} ) on earth’s surface is A. ( 0.32 G ) в. ( 0.32 T ) c. ( 0.32 times 10^{-4} G ) D. ( 0.32 times 10^{-5} T ) | 12 |

177 | If ( delta_{1} ) and ( delta_{2} ) are the angles of dip observed in two vertical planes at right angles to each other and ( delta ) is the true value of dip then : A ( cdot tan ^{2} delta=tan ^{2} delta_{1}+tan ^{2} delta_{2} ) B . ( cot ^{2} delta=cot ^{2} delta_{1}+cot ^{2} delta_{2} ) ( ^{mathrm{C}} tan ^{2} delta=frac{tan ^{2} delta_{1}+tan ^{2} delta_{2}}{tan ^{2} delta_{1} tan ^{2} delta_{2}} ) D. ( cot ^{2} delta=1+cot ^{2} delta_{1} cos ^{2} delta_{2} ) | 12 |

178 | used to plot the magnetic field around a bar magnetic field around a bar magnet with poles marked ( N ) (North) and ( S ) (South). Which of the following diagrams correctly shows the expected field pattern? ( A ) B. ( c ) ( theta ) D. | 12 |

179 | State whether the following statement is True or False. Ampere’s swimming rule describes the direction of magnetic lines of force in a straight conductor. | 12 |

180 | Resultant force acting on a diamagnetic material in a magnetic field is in direction. A. From stronger to the weaker part of the magnetic field B. From weaker to the stronger part of the magnetic field c. Perpendicular to the magnetic field D. In the direction making ( 60^{circ} ) to the magnetic field | 12 |

181 | The meniscus of a liquid contained in one of the limbs of a narrow U-tube is held electromagnet with the meniscus in line with the field. The liquid is seen to rise. This indicates that the liquid is A. anti-ferromagneticç B. paramagnetic c. diamagnetic D. non-magnetic | 12 |

182 | A dip circle is at right angle to the magnetic meridian. The apparent dip angle is A. ( 0^{circ} ) B. ( 30^{circ} ) ( c cdot 60^{circ} ) D. ( 90^{circ} ) | 12 |

183 | Three magnets of the same length but moments ( mathrm{M}, 2 mathrm{M} ) and ( 3 mathrm{M} ) are arranged in the forms of an equilateral triangle with opposite pole nearer, the resultant magnetic moment of the arrangement is? A. 6 м B. zero c. ( sqrt{3} ) м D. ( frac{sqrt{3}}{2} ) M | 12 |

184 | Explain Curie’s law for a paramagnetic substance. | 12 |

185 | Hysteresis is shown by which of the following materials A. paramagnetic only B. ferromagnetic only c. diamagnetic only D. both B and C | 12 |

186 | A charged particle, initially at rest at 0 when released follows a trajectory as shown. Such a trajectory is possible in the presence of. A. Electric field of constant magnitude and varying direction B. Magnetic field of constant magnitude and varying direction C. Electric filed of constant magnitude and constant direction D. Electric and magnetic fields of constant magnitudes and constant directions which are parallel to each other | 12 |

187 | State Tangent Law in magnetism. | 12 |

188 | The force acting on a pole of strength of ( 20 mathrm{Am} ) is ( 8 times 10^{-4} mathrm{N}, ) when placed in a magnetic field. The magnetic induction field strength is : A. ( 4 times 10^{-6} ) т B. ( 0.4 times 10^{4} mathrm{T} ) ( c cdot 4 G ) D. ( 4 times 10^{-5} mathrm{T} ) | 12 |

189 | 52. A paramagnetic material is kept in a magnetic field. The field is increased till the magnetisation becomes constant. If the temperature is now decreased, the magnetisation (a) will increase (b) decreases (c) remain constant (d) may increase or decrease 2 Ti • 1- 1 | 12 |

190 | Nickel shows ferromagnetic property at room temperature. If the temperature is increased beyond Curie temperature, then it will show: A. paramagnetism B. anti-ferromagnetism c. no magnetic property D. diamagnetism | 12 |

191 | If a magnetic material is having magnetic susceptibility ( (chi)=-1, ) then the relative magnetic permeability ( left(mu_{r}right) ) and type of magnetic material is? A. ( 0, ) diamagnetic B. 2, ferromagnetic c. 1 , paramagnetic D. -1, diamagnetic | 12 |

192 | carrying current ( i_{0} ) lies in the ( x ) -y plane as shown in the figure. It is hinged at ( y^{-} ) axis so that it can freely route about it. Moment of inertia of the loop about an axis through its c.m. and normal to its plane is equal to ( gamma M a^{2} . A t t=0, ) an external magnetic field of induction B is applied along +ve x axis. The initial angular acceleration of the loop is equal to A ( cdot frac{4 i_{0} B}{M(2 gamma+1)} ) В. ( frac{i_{0} B}{M gamma} ) c. ( frac{4 i_{0} pi B}{M(2 gamma+1)} ) D. ( frac{4 i_{0} B}{(2 gamma+1)} ) | 12 |

193 | Meena draws magnetic field lines of the field close to the axis of a current carrying circular loop. As she moves away from the center of the circular loop she observes that the lines keep A. on diverging B. on converging c. diappearing D. none | 12 |

194 | The vertical component of earth’s magnetic field at a place is ( sqrt{3} ) times the horizontal component the value of angle of dip at this place is? A ( .30^{circ} ) B . ( 45^{circ} ) ( c cdot 60^{circ} ) D. ( 90^{circ} ) | 12 |

195 | Write two properties of a material suitable for making (a) a permanent magnet, and (b) an electromagnet. | 12 |

196 | Magnetic dipole moment is a vector quantity directed from: A. south to North pole B. North to south pole c. East to west direction D. west to East direction | 12 |

197 | A frog can jump higher than normal in a magnetic field because the tissues of a frog are A. paramagnetic B. diamagnetic c. ferromagnetic D. antiferro magneticc | 12 |

198 | Two magnetic dipoles are lying as shown in figure. the separation ‘ ( d ) between them is very large. A point charge ( Q ) is projected with some speed ( v ) as shown. The force experienced by the charged particle is: A . 0 B. ( frac{4 sqrt{2} mu_{0} M Q v}{pi d^{3}} ) c. ( frac{sqrt{2} mu_{0} M Q v}{pi d^{3}} ) D. ( frac{2 sqrt{2} mu_{0} M Q v}{pi d^{3}} ) | 12 |

199 | Which of the following is/are true for “magnetic lines of force around a bar magnet”? A. are closed continuous curves B. travel from north to south outside the magnet c. bend around the length of magnet D. all the above | 12 |

200 | State whether true or false. Magnetic lines of force are primarily curved lines. A. True B. False | 12 |

201 | Which of the following best describes the field due to a magnet? A. The region where its effects are felt B. The two regions close to its poles c. The region between its poles D. The region where it aligns itself along the north-south direction | 12 |

202 | When an iron cylinder of diameter ( 0.20 mathrm{cm} ) and length ( 30 mathrm{cm} ) is kept parallel to a magnetic field of intensity ( 4800 A / m ) the cylinder acquires a pole strength of ( 9 A m . ) Find the permeability of the material of the rod? A ( .0 .075222 times 10^{-4} mathrm{H} / mathrm{m} ) B . ( 9.522 times 10^{-4} mathrm{H} / mathrm{m} ) c. ( 75.22 times 10^{-4} mathrm{H} / mathrm{m} ) D. ( 7.522 times 10^{-4} mathrm{H} / mathrm{m} ) | 12 |

203 | A thin diamagnetic rod is placed vertically between the poles of an electromagnet. When the current in the electromagnet is switched on, then the diamagnetic rod is pushed up, out of the horizontal magnetic field. Hence the rod gains gravitational potential energy. The work required to do this comes from A. The lattice structure of the material of the rod B. The current source c. The induced electric field due to the changing magnetic field D. The magnetic field | 12 |

204 | The material used for permanent magnet has: A. low retentivity, high coercivity B. high retentivity, low coercivity c. high retentivity, high coercivity D. low retentivity, , low coercivity | 12 |

205 | Which of the following cannot be ferromagnetic? This question has multiple correct options | 12 |

206 | A dip needle lies initially in the magnetic meridian when it shows an angle of dip ( theta ) at a place. The dip circle is rotated through an angle ( x ) in the horizontal plane and then it shows an angle of ( operatorname{dip} theta ) ‘. Then ( frac{tan theta^{prime}}{tan theta} ) is A ( cdot frac{1}{cos x} ) B. ( frac{1}{sin x} ) c. ( frac{1}{tan x} ) D. ( cos x ) | 12 |

207 | The value of magnetic susceptibility for para-magnetic substance is A . infinity B. low positive c. low negative D. zero | 12 |

208 | Two like magnetic poles of strength 10 and ( 40 S I ) units are separated by a distance ( 30 c m . ) The intensity of magnetic field is Zero on the line joining them. A. At a point ( 10 mathrm{cm} ) from stonger pole. B. At a point ( 20 mathrm{cm} ) from stonger pole. c. At a mid-point. D. At infinity. | 12 |

209 | A rectangle with its dimensions is as shown. A Magnetic mono pole of pole strength ‘ ( mathrm{m}^{prime} ) is placed at the point ( ^{prime} mathrm{A}^{prime} ) and another pole of pole strength ‘5m’ is placed at the point ‘B’. The magnetic force acting between them is ‘F’.’ If magnetic pole at the point ‘B’ is moved to the point ‘C’, Find final magnetic force acting between them. A ( cdot frac{F}{10} ) в. ( frac{F}{17} ) ( c cdot frac{F}{20} ) ( mathbf{D} cdot F ) | 12 |

210 | Magnetic field can be defined as the: A. space surrounding the magnet in which magnetic force acts B. space surrounding the magnet in which electric force acts C. space surrounding the magnet in which no force acts D. none | 12 |

211 | A dip needle shows an angle of dip ( theta ) in a place which is in the magnetic meridian. Now, the dip circle is rotated through an angle ( x ) in the horizontal plane and then it shows an angle of dip ( theta_{1} . ) Value of ( tan theta_{1} / tan theta ) is : A ( cdot frac{1}{cos x} ) B. ( frac{1}{sin x} ) c. ( frac{1}{tan x} ) D. ( cos x ) | 12 |

212 | Define magnetic inclination or angle of dip. | 12 |

213 | Choose the correct option which describe the magnetic field produced by a current in a long, straight wire? A. The field in uniform B. The field increases in strength as the distance from the wire increases c. The field lines are directed parallel to the wire, but opposite to the direction of the current D. The field lines are directed radially outward from the wire E. The field lines form circles about the wire | 12 |

214 | Lines of force A. are not imaginary lines B. cannot be mapped on paper c. do not intersect each other D. always intersect each other | 12 |

215 | Two short magnets with pole strengths of ( 900 A m ) and ( 100 A m ) are placed with their axes in the same vertical line, with similar poles facing each other. Each magnet has a length of ( 1 mathrm{cm} ). When separation between the nearer poles is ( 1 mathrm{cm}, ) the weight of the upper magnet is supported by the repulsive force between the magnets. If ( g=10 m s^{-2} ), then the mass of upper magnet is ( left(x times 10^{-4}right) ) A. ( 1.6 k g ) в. ( 2.4 k g ) c. ( 5.5 k g ) D. ( 4.8 k g ) | 12 |

216 | A point near the equator has: ( mathbf{A} cdot B_{V}>>B_{H} ) ( mathbf{B} cdot B_{H}>>B_{V} ) ( mathbf{c} cdot B_{V}=B_{H} ) D ( . B_{V}=B_{H}=0 ) | 12 |

217 | In the given figure, the electron enters into the magnetic field. It deflects in ( x ) direction Two parallel beams of electrons moving in the same direction produce a mutual force | 12 |

218 | What are magnetic field lines? How is the direction of magnetic field at a point in a magnetic field determined using field lines? | 12 |

219 | At the magnetic north pole of the earth, the value of the horizontal component of earth’s magnetic field and angle of dip are respectively. A. zero, maximum B. maximum,minimum c. maximum,maximum D. minimum,minimum | 12 |

220 | Classify the following materials with regard to magnetism: Manganese, Cobalt, Nickel, Bismuth, Oxygen and Copper | 12 |

221 | Core of electromagnets are made of ferromagnetic material which has: A. High permeability and Low retentivity B. High permeability and High retentivity c. Low permeability and High retentivity D. Low permeability and Low retentivitty | 12 |

222 | 35. A magnet is suspended in such a way that it oscillates in the horizontal plane. It makes 20 oscillations per minute at a plane where dip angle is 30° and 15 oscillations per minute at a place where dip angle is 60°. The ratio of earth’s magnetic field at two places is (a) 3v3:8 (b) 16:9 V3 (c) 4:9 (d) 2V2:3 | 12 |

223 | The substances which are attracted towards a magnet are called A. metals B. ferro-magnetic materialss c. non-metals D. dia-magnetic materials | 12 |

224 | If ( M_{2}= ) magnetization of a paramagnetic sample, ( mathrm{B}= ) external magnetic field, ( T= ) absolute temperature, ( C= ) curie constant then according to Curie’s law in magnetism, the correct relation is A ( cdot M_{z}=frac{T}{C B} ) В. ( quad M_{z}=frac{C B}{T} ) ( ^{mathrm{c}} cdot_{C}=frac{M_{z}}{T} ) D. ( _{C}=frac{T^{2}}{M_{z} B} ) | 12 |

225 | A magnetic needle free to rotate in a vertical plane parallel to the magnetic meridian has its North tip pointing down at ( 22^{0} ) with the horizontal. the horizontal component of the earth’s magnetic field at the place is known to be 0.35 G.The magnitude of the earth’s magnetic field at the place will be:- A . 0.68 G B. 0.36 G ( c cdot 0.83 G ) D. 0.86 G | 12 |

226 | Which of the following independent quantities is not used to specify the earth’s magnetic field.? A. Magnetic declination ( (theta) ) B. Magnetic dip. C. Horizontal component of earth’s field ( left(B_{H}right) ) D. Vertical component of earth’s field ( left(B_{V}right) ) | 12 |

227 | Assertion At high temperature, a ferromagnet becomes a paramagnet. Reason The ferromagnetic property depends on temperature. 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 |

228 | A strong magnetic field is applied on a stationary electron. Then A. the electron moves in the direction of the field B. the electron moves in an opposite c. the electron remains stationary D. the electron starts spinning | 12 |

229 | Magnetic force required to demagnetize the material A. retainity B. coercivity c. energy loss D. hysteresis | 12 |

230 | Show diagrammatically the behaviour of magnetic field lines in the presence of (i) paramagnetic and (ii) diamagnetic substances. How does one explain this distinguishing feature? | 12 |

231 | A strong bar magnet placed vertically above a horizontal wooden board. The magnetic lines of force will be A. only in horizontal plane around the magnet B. only in vertical plane around it magnet. c. in horizontal as well as vertical plane around the magnet D. in all the planes around the magnet | 12 |

232 | Assertion Magnetic force between two short magnets, when they are co-axial follows inverse square law of distance. Reason The magnetic forces between two poles do not follow inverse square law of distance. 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 |

233 | At a place, the horizontal and vertical components of earth’s magnetic field are equal. What is the angle of dip at that place? A . 45 B. 55 ( c cdot 65 ) D. 76 | 12 |

234 | The angle of dip at a place on the earth gives: A. The horizontal component of the earth’s magnetic field. B. The location of geograhical meridian. C. The vertical component of the earth’s magnetic field. D. The direction of the earth’s magnetic field. | 12 |

235 | If the magnetic moment of magnet is ( 0.8 times 10^{-3} A m^{2} ) and the force acting on each pole in a uniform magnetic field strength of 0.48 gauss, is ( 0.512 times 10^{-6} N ) The distance between the poles of the magnet is : (in ( c m) ) A . 25 в. 12.5 c. 15 D. 7.5 | 12 |

236 | A particle of mass ( m ) and positive charge ( boldsymbol{q}, ) moving with a uniform velocity ( v, ) enters a magnetic field ( B ) as shown in figure. (a) Find the radius of the circular arc it describes in the magnetic field (b) Find the angle subtended by the arc at the centre (c) How long does the particles stay inside the magnetic field? (d) Solve the three parts of the above problems if the charge ( q ) on the particle is negative then. | 12 |

237 | A short bar magnet has a magnetic moment of ( 0.48 J T^{-1} . ) Give the direction and magnitude of the magnetic field produced by the magnet at a distance of ( 10 mathrm{cm} ) from the centre of the magnet on (a) the axis, (b) the equatorial lines (normal bisector) of the magnet | 12 |

238 | The value of susceptibility for super conductor is ( A cdot O ) ( B . infty ) ( mathbf{C} cdot+1 ) D. – – | 12 |

239 | Three identical specimens of a magnetic materials nickel, antimony and aluminium are kept in a nonuniform magnetic field. Draw the modification in the field line in each case. Justify your answer. | 12 |

240 | The permanent magnetic moment of atoms or molecules of a diamagnetic material is A. small B. large c. negative D. zero | 12 |

241 | Magnetic lines of force are: A. continuous B. discontinuous c. some times continuous and some times discontinuous D. nothing can be said | 12 |

242 | A small rod of bismuth is suspended freely between the poles of a strong magnet. It is found to arrange itself at right angles to the magnetic field. What is established by the observation? | 12 |

243 | If a magnet of pole strength ( mathrm{m} ) is divided into four parts such that the length and width of each part is half that of the initial one, then the pole strength of each part will be ( A cdot m / 4 ) B. m/2 ( c cdot m / 8 ) D. ( 4 mathrm{m} ) | 12 |

244 | 67. The dipole moment of each molecule of a parama gas is 1.5 x 10-4 A x mʻ. The temperature of a 27°C and the number of molecules per unit volume it is 2 x 1026 m . The maximum possible intensity of magnetisation in the gas will be (a) 3 x 10° A/m (b) 4 x 10-‘A/m (c) 5 x 10° A/m (d) 6 x 104 A/m | 12 |

245 | The angle of dip at a certain place where the horizontal and vertical components of the earth’s magnetic field are equal is? A ( .30^{circ} ) B . ( 75^{circ} ) ( c cdot 60^{circ} ) D. ( 45^{circ} ) | 12 |

246 | The magnetic field intensity due to a magnet is ( frac{100}{4 pi} mathrm{A} / mathrm{m} ). The induction field strength due to it is : ( mathbf{A} cdot 1 times 10^{-5} T ) в. ( frac{4 pi}{10^{3}} T ) c. ( frac{10^{3}}{4 pi} times 100 T ) D. ( frac{10^{-5}}{4 pi} T ) | 12 |

247 | Angle of dip at a place is ( 60^{0} ) and earth’s magnetic field is ( 8 mu T . ) Its horizontal component ( boldsymbol{B}_{boldsymbol{H}} ) is : A ( .4 sqrt{3 mu} T ) в. ( 4 mu T ) c. ( frac{8}{sqrt{3}} mu T ) D. ( 8 sqrt{3 mu} T ) | 12 |

248 | Two short bar magnets with magnetic moments 400 ab ( A c m^{2} ) and ( 800 a b A ) ( c m^{2} ) are placed with their axis in the same straight line with similar poles facing each other and with their centres at ( 20 mathrm{cm} ) apart from each other. Then the force of repulsion is: Disclaimer: No option as 0.08 dyne was given in the original paper. A. 12 dyne B. 6 dyne c. 0.08 dyne D. 150 dyne | 12 |

249 | Force between two identical bar magnets whose centres are rmeters apart is ( 4.8 N ) when their axis are in the same line. If the separation is increased to ( 2 r ) meters, the force between them is reduced to: A. 2.4 B. 1.2 N c. ( 0.6 mathrm{N} ) D. 0.3 N | 12 |

250 | When the atomic magnetic moments are randomly oriented in a solid its magnetic behavior is termed as A. semi-magnetic. B. anti-ferromagnetic C. paramagnetic. D. poly crystalline. | 12 |

251 | The hysteresis cycle curve for the material of a permanent magnet is: A. short and wide B. tall and narrow c. tall and wide D. short and narrow | 12 |

252 | Curie-Weiss law is obeyed by iron: A. at Curie temperature only. B. at all temperatures. C . below Curie temperature. D. above Curie temperature. | 12 |

253 | Assertion: When diamagnetic material is placed in a non-uniform magnetic field, it tends to move from stronger to the weaker part of the magnetic field. Reason : Diamagnetic materials possess strong magnetism. A. If both assertion and reason are true and reason is the correct explanation of assertion. B. If both assertion and reason are true and reason is not the correct explanation of assertion. c. If assertion is true but reason is false D. If both assertion and reason are false | 12 |

254 | The strength of the magnetic field around a straight conductor: A. is same everywhere around the conductor B. obeys inverse square law C. is directly proportional to the square of the distance from the conductor D. none of these | 12 |

255 | Assertion(A): If one arm of a ( U ) -tube containing a diamagnetic solution is placed in between the poles of a strong magnet with the level in line with the field, the level of the solution falls Reason(R): Diamagnetic substances are repelled by the magnetic field A. both ( A, R ) are true and ( R ) is the correct explanation of B. both A,R are true and R is not correct explanation of A c. A is true, R is false D. A is false R is true | 12 |

256 | At magnetic poles, the angle of dip is A ( cdot 45^{circ} ) B . ( 30^{circ} ) c. zero D. ( 90^{circ} ) | 12 |

257 | The hysteresis cycle for the material of a transformer core is? A. Short and wide B. Tall and narrow c. Tall and wide D. short and narrow | 12 |

258 | Curie temperature is the temperature above which A. a ferromagnetic material becomes paramagnetic B. a paramagnetic material becomes diamagnetic C . a ferromagnetic material becomes diamagnetic D. a paramagnetic material becomes ferromagnetic | 12 |

259 | 19 The variation of magnetic susceptibility (W) with magnetising field for a paramagnetic substance is (+) f (b) + O Exo lor (d) TH 18The unrintion of magnetic susceptibility (y) with absolute | 12 |

260 | Distinguish between ‘paramagnetic’ and ‘ferromagnetic’ substances. | 12 |

261 | Magnetic equator is A. Isoclinic line B. Aclinic line C. Isogonic line D. Agonic line | 12 |

262 | State True or False. Magnetic lines of force do not intersect A. True B. False | 12 |

263 | Which metal is used to make ferromagnets? A. Iron B. cobalt c. Nickel D. All of these | 12 |

264 | Magnetic susceptibility ( chi ) of a paramagnetic material changes with absolute temperature ( T ) as A ( cdot chi propto T^{-1} ) B. ( x= ) constant c. ( chi propto e^{r} ) D. ( chi propto T ) | 12 |

265 | The horizontal component of earth’s magnetic field at a certain place is ( 3.0 times 10^{-5} mathrm{T} ) and having a direction from the geographic south to geographic north. The force per unit length on a very long straight conductor carrying a steady current of ( 1.2 mathrm{A} ) in east to west direction is then A. ( 3.0 times 10^{-5} mathrm{N} mathrm{m}^{-1} ) В. ( 3.2 times 10^{-5} mathrm{N} mathrm{m}^{-1} ) c. ( 3.6 times 10^{-5} mathrm{N} mathrm{m}^{-1} ) D. ( 3.8 times 10^{-5} mathrm{N} mathrm{m}^{-1} ) | 12 |

266 | A bar magnet of magnetic moment ( 1.2 A m^{2} ) is placed in the magnetic meridian with its south pole pointing the north. If a neutral point is found at a distance of ( 20 mathrm{cm} ) from the centre of the magnet, the value of the horizontal component of the earth’s magnetic field is : A. ( 3 times 10^{-5} T ) B. ( 3 times 10^{-4} T ) c. ( 3 times 10^{3} T ) D. ( 3 times 10^{-2} T ) | 12 |

267 | Assertion Basic difference between an electric line of force and magnetic lines of force is that former is discontinuous and the latter is continuous or endless. Reason No electric lines of force exist inside a charged body but magnetic lines do exist inside a magnet. 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 |

268 | A positively charged particle in a uniform magnetic field moves in a circular path in the clockwise direction, parallel to the plane of the page. In what direction do the magnetic field lines point? A. Out of the page B. Into the page c. To the left D. To the right E. In a clockwise pattern parallel to the plane of the page | 12 |

269 | The relative permeability is represented by ( mu_{r} ) and the susceptibility by ( chi ) for a magnetic substance. Then, for a paramagnetic substance. Then, for a paramagnetic substance A ( cdot mu_{r}>1, chi>0 ) в. ( mu_{r}>1, chi1, chi>0 ) D. ( mu_{r}<1, chi<0 ) | 12 |

270 | Assertion: A soft iron core is used in a moving coil galvanometer to increase the strength of magnetic field Reason: From soft iron more number of the magnetic lines of force passes A. Both A and R are true and R is the correct explanation of A B. Both A and R are true and R is not correct explanation of c. A is true, but R is false D. A is false, but R is true | 12 |

271 | The magnetic susceptibility of an ideal diamagnetic substance is A . – B. ( c cdot+1 ) ( D cdot alpha ) | 12 |

272 | Which of the following is universal magnetic property.? A. Ferromagnetism B. Diamagnetism c. Paramagnetism D. Anti-ferromagnetism. | 12 |

273 | If a magnet is suspended at an angle ( 30^{circ} ) to the magnetic meridian, the dip needle makes an angle of ( 45^{circ} ) with the horizontal. The real dip is: A ( cdot tan ^{-1}(sqrt{3 / 2}) ) B. ( tan ^{-1} sqrt{3} ) ( ^{mathrm{c}} tan ^{-1}(sqrt{frac{2}{3}}) ) D ( cdot tan ^{-1}left(frac{2}{sqrt{3}}right) ) | 12 |

274 | The work done in rotating a bar magnet of magnetic moment ( M ) from its unstable equilibrium position to its stable equilibrium position in a uniform magnetic field ( B ) is ( mathbf{A} cdot 2 M B ) в. ( M B ) c. ( -M B ) D. ( -2 M B ) | 12 |

275 | Assertion (A): Poles of a magnet can never be separated Reason (R): Since, each atom of a magnetic material is a magnet in itself A. Both A and R are true and R is the correct explanation of A B. Both A and R are true and R is not correct explanation of A C. A is true, but R is false D. A is false, but R is true | 12 |

276 | The value of earth’s magnetic field can be A . ( 0.5 G ) в. ( 5 G ) ( c cdot 10 G ) D. ( 50 G ) | 12 |

277 | 44. A ferromagnetic material is heated above its temperature. Which one is a correct statement? (a) Ferromagnetic domains are perfectly arranged (b) Ferromagnetic domains becomes random (c) Ferromagnetic domains are not influenced (d) Ferromagnetic material changes itself into diamagnetic material | 12 |

278 | Metals getting magnetised by orientation of atomic magnetic moments in external magnetic field are called A. diamagnetics B. paramagnetics c. ferromagnetics D. antimagnetics | 12 |

279 | Obtain an expression for magnetic flux density B at the centre of a circular coil of radius ( mathrm{R} ), having ( mathrm{N} ) turns and carrying a current ( boldsymbol{I} ) | 12 |

280 | A straight wire lying in a horizontal plane carries a current from north to south. What will be the direction of magnetic field at a point just underneath it? A. Towards north. B. Towards east c. Towards west D. Towards south. | 12 |

281 | In a vertical plane ( p_{1} ) making angle ( 30^{circ} ) with magnetic meridian, apparent angle of dip in vertical plane ( p_{2} ) is ( 60^{circ} ) which is perpendicular to plane ( p_{1} ) is: A ( .30^{circ} ) B . ( 45^{circ} ) ( mathbf{c} cdot tan ^{-1}(3) ) D. ( tan ^{-1}left(frac{2}{3}right) ) | 12 |

282 | Curie temperature is the temperature above which A. a ferromagnetic material becomes paramagnetic B. a paramagnetic material becomes diamagnetic C . a ferromagnetic material becomes diamagnetic D. a paramagnetic material becomes ferromagnetic. | 12 |

283 | Dip circle is not set into magnetic meridian and the angle at which it is inclined to the magnetic meridian is unknown. ( delta^{prime} ) and ( delta^{prime prime} ) are apparent dips at a place in which dip circle is kept in transverse positions. The dip is: ( mathbf{A} cdot cot delta=cot delta^{prime}+cos delta^{prime prime} ) B. ( tan ^{2} delta^{prime}=tan delta^{prime}+tan ^{2} delta^{prime prime} ) ( mathbf{c} cdot cos ^{2} delta=cos ^{2} delta^{prime}+cos ^{2} delta^{prime prime} ) D. ( cot ^{2} delta=cot ^{2} delta^{prime}+cot ^{2} delta^{prime prime} ) | 12 |

284 | 32. Two bar magnets when placed with their similar poles together makes 20 vib/min. When one of them is reversed the number of vibrations become 15 vib/min. What is the ratio of their dipole moment? (a) 7:45 (b) 25:7 (c) 1:4 (d) 4:1 util ihimmerid 22 an | 12 |

285 | Write definition of Curie temperature for ferromagnetic substance. | 12 |

286 | A magnetic needle free to rotate in a vertical plane parallel to the magnetic meridian has its north tip pointing down at ( 22^{0} ) with the horizontal. The horizontal component of the earth’s magnetic field at the place is known to be ( 0.35 G . ) Determine the magnitude of the earth’s magnetic field at the place. A . 0.12 B. 1.23 ( c cdot 4.56 ) D. 0.38 | 12 |

287 | Due to a small magnet, intensity at a distance ( x ) in the end on position is 9 gauss. What will be the intensity at a distance ( frac{x}{2} ) on broad side on position. A. 9 gauss B. 4 gauss c. 36 gauss D. 4.5 gauss | 12 |

288 | What are magnetic field lines with the properties give direction of magnetic field for a point and an electric dipole | 12 |

289 | 41. Among the following properties describing diamagnetic identify the property that is wrongly stated. (a) Diamagnetic material do not have permanent magneti moment (b) Diamagnetism is explained in terms of electromagnetic induction (c) Diamagnetic materials have a small positive susceptibility (d) The magnetic moment of individual electrons neutralize each other | 12 |

290 | Assertion: Substances which at room temperature retain their ferromagnetic property for a long period of time are called permanent magnets. Reason: Permanent magnet can be | 12 |

291 | Write three properties of ferromagnetic materials. | 12 |

292 | In a long hollow vertical metal pipe a magnet is dropped. During its fall, the acceleration of magnet A. will decrease linearly B. will decrease upto a value which is less than ( g ). c. will decrease to zero and will attain a terminal speed D. may increase or decrease | 12 |

293 | A electron experiences a force ( (4.0 hat{i}+ ) ( mathbf{3} . mathbf{0} hat{boldsymbol{j}}) times mathbf{1 0}^{-mathbf{1 3}} boldsymbol{N} ) in a uniform magnetic field when its velocity is ( 2.5 hat{k} times ) ( 10^{7} m s^{-1} . ) The magnetic field vector ( vec{B} ) is ( mathbf{A} cdot-0.075 hat{i}+0.1 hat{j} ) B. ( 0.1 hat{i}+0.075 hat{j} ) c. ( -0.075 hat{i}-0.1 hat{j}+hat{k} ) D. ( -0.075 hat{i}-0.1 ) | 12 |

294 | Two coils each of 100 turns are held such that one lies in vertical plane and the other in the horizontal plane with their centers coinciding. The radius of the vertical coil is ( 0.20 m ) and that of the horizontal coil is 0.30 m. How will you neutralize the magnetic field of the earth at their common center? If the summation of current to be passed through each coil is ( i_{text {total}}=x A . ) Find ( x^{*} 10 ) Horizontal component of earth’s magnetic field ( =0.35 times 10^{-4} T ) and angle of ( operatorname{dip}=30^{circ} ) | 12 |

295 | A line joining places of zero dip is called A . aclinic B. isoclinic c. isodynamic D. isogonal | 12 |

296 | The magnetising field required to be applied in opposite direction to reduce residual magnetism to zero is called A. coercivity B. retentivity c. hysteresis D. none of these | 12 |

297 | A straight wire carries conventional current toward the sky. What is the direction of the magnetic field due to the current west of the wire? A. North B. South c. East D. west E. Up | 12 |

298 | Materials suitable for permanent magnet, must have which of the following properties? A. High retentivity, low coercivity and high permeability B. Low retentivity, low coercivity and low permeability c. Low retentivity, high coercivity and low permeability D. High retentivity, high coercivity and high permeability | 12 |

299 | A jet plane having a wing-span of ( 25 mathrm{m} ) is travelling horizontally towards east with a speed of ( 3600 mathrm{km} / ) hour. If the Earth’s magnetic field at the location is ( 4 times 10^{-4} mathrm{T} ) and the angle of dip is ( 30^{circ} ) then, the potential difference between the ends of the wing is? A. ( 4 mathrm{v} ) B. 5 v ( c cdot 2 v ) D. 2.5 | 12 |

300 | A small magnet is suspended by a silk thread from a rigid support such that the magnet can freely swing. Describe its behaviour. | 12 |

301 | Answer the question in at least 50 words. Give the characteristic of magnetic | 12 |

302 | What happens to ferromagnetic substance heated above Curie temperature? | 12 |

303 | A short bar magnet of moment ( 3.2 A m^{2} ) lies in magnetic meridian with its north pole pointing north. A neutral point is obtained at a distance of ( 20 mathrm{cm} ) from the centre of the magnet. Find the horizontal. | 12 |

304 | Which of the following is correct about the earth’s magnetic field? A. Earth’s magnetic field is nearly dipolar B. It is approximately aligned with earth’s rotation axis c. It spontaneously reverses every 200,000 years D. All of these | 12 |

305 | What are diamagnetic substances? | 12 |

306 | Current of ( 2 A ) passing through a coil of 100 turns gives rise to a magnetic flux of ( 5 times 10^{-3} W b ) per turn. The magnetic energy associated with coil is ( mathbf{A} cdot 5 times 10^{-3} J ) B. 5.5 c. ( 0.5 times 10^{-3} J ) D. ( 0.5 J ) | 12 |

307 | Derive expression for the intensity of magnetic field at a point in end on position due to a short bar magnet | 12 |

308 | Which of the following shows that the earth behaves as a magnet? A. Repulsion between like poles B. Attraction between unlike poles C. Existence of null points in the magnetic field of a bar magnet D. Non existence of monopoles | 12 |

309 | At Curie temperature the ferromagnetic materials get converted into. A. non-magnetic material B. para magnetic material. c. dia magnetic material. D. all of the above. | 12 |

310 | If the magnetizing field on a ferromagnetic material is increased, its permeability A . Decreased B. Increased c. Is unaffected D. May be increased or decreased | 12 |

311 | A paramagnet magnet behaves like a solenoid because both contain currents in the form of A. Circles B. Parabola c. Straight line D. Ellipse | 12 |

312 | On applying an external magnetic field, to a ferromagnetic substance domains. A. Align in the direction of magnetic field. B. Align in the direction opposite to magnetic field c. Remain unaffected D. align randomly | 12 |

313 | The diagram shows two magnets and two iron rods placed in a line. Which magnetic poles are induced at the ends ( J ) and ( K ) of the iron rods? | 12 |

314 | The magnetic field produced by a current carrying solenoid is similar to the magnetic field produced by a bar magnet. | 12 |

315 | Mark the correct set of ferromagnetic substances A. iron, cobalt and nickel B. iron, copper and lead c. silicon, bismuth and nickel D. aluminium, sodium and copper. | 12 |

316 | If horizontal and vertical components of the earth’s magnetic field are equal at a certain place, then the angle of the dip at that place will be A ( cdot 90^{circ} ) B. ( 60^{circ} ) ( c cdot 45^{circ} ) D. ( 0^{circ} ) | 12 |

317 | Two point charges in air at a distance of ( 20 c m . ) from each other interact with a certain force. At what distance from each other should these charges be placed in oil of relative permittivity 5 to obtain the same force of interaction A. ( 8.94 times 10^{-2} mathrm{m} ) В. ( 0.894 times 10^{-2} mathrm{m} ) ( c cdot 89.4 times 10^{-2} m ) D. ( 8.94 times 10^{2} m ) | 12 |

318 | Liquids and gases never exhibit A. diamagnetic properties B. para magnetic properties C . ferro magnetic properties D. electro magnetic properties | 12 |

319 | If the distance between two unlike poles is doubled then the force of attraction between them becomes times its original value. A ( cdot frac{1}{2} ) B. ( frac{1}{4} ) ( c cdot 2 ) D. 4 | 12 |

320 | The area enclosed by a hysteresis loop is a measure of A. retentivity B. susceptibility c. permeability D. energy loss per cycle | 12 |

321 | The energy band gap of a superconductor formed near the critical temperature is due to A. the exponential decrease in heat capacity B. the exponential increase in heat capacity c. the gradually decrease in heat capacity D. the gradually increase in heat capacity | 12 |

322 | What are the different elements of earth’s magnetism? What is the relation between them? | 12 |

323 | Consider the following statements: (i) Soft iron conducts electricity (ii) Soft iron is magnetic material (iii) Soft iron is used for magnetic permanent magnets (iv) Soft iron is used as electro magnet A. (i) and (ii) are correct B. (i) and (iii) are correct c. (ii) and (iv) are correct D. (i), (ii) and (iv) are correct | 12 |

324 | The magnetic field of the earth can be modelled by that of a point dipole placed at the centre of the earth. The dipole axis makes an angle of ( 11.3^{circ} ) with the axis of the earth. At Mumbai, declination is nearly zero. Then, A. The declination varies between ( 11.3^{circ} mathrm{W} ) to ( 11.3^{circ} mathrm{E} ) B. The least declination is ( 0^{circ} ) C. The plane defined by dipole axis and the earth axis passes through Greenwich D. Declination averaged over the earth must be always negative | 12 |

325 | Nickel shows ferromagnetic property at room temperature. If the temperature is increased beyond Curie temperature then it will show A. diamagnetism B. paramagnetism c. anti ferromagnetism D. no magnetic property | 12 |

326 | The most important features of superconductor is that A. once current is set up in a superconductor ring, it will continue indefinitely even if the battery is off B. it has high efficiency compared to other conductors C. it can pass maximum no of electrons when current is passed through it. D. none of the above | 12 |

327 | State any two properties of magnetic lines of force. | 12 |

328 | Iron loses magnetic property at: A. melting point В. ( 1000 K ) C . curie point D. boiling point | 12 |

329 | Two identical bar magnets are held perpendicular to each other with a certain separation, as shown below. The area around the magnets is divided into four zones. Given that there is a neutral point it is located in. A. Zone I B. Zone II C. Zone III D. Zone IV | 12 |

330 | A dip needle shows angle of dip ( theta ) when the dip circle is placed in magnetic meridian. Now, the dip circle is rotated by an angle ( alpha ) and the apparent angle of dip at this place is ( theta^{prime} ), then ( left(tan theta^{prime} / tan thetaright) ) is : A . ( 1 / cos alpha ) B. ( 1 / sin alpha ) ( c cdot cos alpha ) D. sina | 12 |

331 | 60. Figure shows a short magnet executing small oscillations in a vibration magnetometer in earth’s magnetic field having horizontal component w 24 u T. The period of oscillation is 0.1 s. When the key K is closed, an upward current of 18 A is established as shown. The new time period is (a) 0.1 s (b) 0.2 s (c) 0.3 s (d) 0.4 s 11 0.2 m | 12 |

332 | The critical temperature for superconductors is the temperature at which the electrical resistivity of a metal A. drops to zero B. increase to maximum limit c. decrease to a certain limit D. none of the above | 12 |

333 | For soft iron, in comparison with steel: A. hysteresis loss is more B. hysteresis loss is same C. hysteresis loss is less D. hysteresis loss is negligible | 12 |

334 | The value of Curie temperature for ( N i ) is nearly ( mathbf{A} cdot 631 K ) B. ( 770 K ) ( mathbf{c} .890 K ) D. ( 1100 K ) | 12 |

335 | What we have learnt about heating effect of electric current. In studied about magnets and magnetic lines of force | 12 |

336 | The figure gives experimentally measured B vs. H variation in a ferromagnetic material. The retentivity co-ercivity and saturation, respectively, of the material are : A. ( 1.5 T, 50 A / m ) and 1.07 B. ( 150 A / m, 1.0 T ) and ( 1.5 T ) c. ( 1.5 T, 50 A / m ) and 1.07 D. ( 1.0 T, 50 A / m ) and 1.57 | 12 |

337 | 51. If a magnetic substance is kept in a magnetic field, then which of the following is thrown out? (a) Paramagnetic (b) Ferromagnetic (c) Diamagnetic (d) Antiferromagnetic | 12 |

338 | What is ( mu_{max } ) equal to? A ( cdot mu_{max } approx 1.0 times 10^{4} ) B . ( mu_{max } approx 2.0 times 10^{4} ) C ( cdot mu_{max } approx 1.0 times 10^{3} ) D. ( mu_{max } approx 2.0 times 10^{3} ) | 12 |

339 | The correct value of dip angle at a place is ( 45^{circ} . ) If the dip circle is rotated by ( 45^{circ} ) out of the meridian, then the tangent of the angle of apparent dip at the place is : A . в. 0.5 c. ( frac{1}{sqrt{2}} ) D. ( sqrt{2} ) | 12 |

340 | Alloys of ferromagnetic materials A. are always ferromagnetic in nature B. need not be ferromagnetic in nature C . are always diamagnetic in nature D. are always antiferromagnetic in nature | 12 |

341 | The magnetising field required to be applied in opposite direction to reduce residual magnetism to zero is called A. retentivity B. coercivity c. hysteresis D. flux | 12 |

342 | The resultant magnetic field at the center of a bar magnet is zero. A. True B. False | 12 |

343 | At a place, the angle of dip is ( 30^{0} . ) If the horizontal component of earth’s field is ( B_{H}, ) then the net field intensity at the place will be : A ( cdot frac{B_{H}}{2} ) в. ( frac{2 B_{H}}{sqrt{3}} ) c. ( B_{H} sqrt{2} ) D. ( B_{H} sqrt{3} ) | 12 |

344 | The angle of dip at equator is ( mathbf{A} cdot 0^{circ} ) В . ( 45^{circ} ) ( c cdot 60^{circ} ) D. ( 90^{circ} ) | 12 |

345 | Two magnetic poles of strengths ( 40 A m ) and ( 10 A m ) are separated by a distance of ( 20 mathrm{cm} ) in air. The force between them if the distance is reduced to ( 10 mathrm{cm} ) is A ( cdot 4 times 10^{-3} N, 10^{-3} N ) B . ( 10^{-3} N, 4 times 10^{-3} N ) c. ( 2 times 10^{-3} N, 10^{-3} N ) D. ( 10^{-3} N, 2 times 10^{-3} N ) | 12 |

346 | A rectangle has sides of lengths ( 6 mathrm{cm} ) and ( 8 c m . ) Two magnetic poles each of pole strength ‘ ( m ) ‘ are placed at the ends of one side of smaller length and magnetic force acting between them is ( F^{prime} . ) If they are moved to new positions of same rectangle so that they are diagonally opposite. Find the final force acting on each pole. | 12 |

347 | The angle of dip increases as we move from A. Poles to equator B. Equator to poles c. Dip is equal at all places D. None of these | 12 |

348 | The isoclinic lines on magnetic map represent lines of A. zero dip B. equal declination c. equal dip D. equal horizontal field | 12 |

349 | Two south poles each of pole strength 16 A m are placed at corners ( P, R ) of a square PQRS. The pole that should placed at ‘Q’ to make S as null point is : A. South pole of pole strength 32 A m B. South pole of pole strength ( 32 sqrt{2} ) A ( m ) c. North pole of pole strength 32 A m D. North pole of pole strength ( 32 sqrt{2} ) A ( m ) | 12 |

350 | Two straight infinitely long and thin parallel wires are spaced ( 0.1 mathrm{m} ) apart and carry a current of 10 ampere each. Find the magnetic field at a point distant ( 0.1 mathrm{m} ) from both wires in the two cases when the currents are in the : 1) Same and 2) Opposite direction. | 12 |

351 | The magnetic field due to a current carrying loop of radius ( 12 mathrm{cm} ) at its centre is ( 0.5 times 10^{-4} ) T. Find the magnetic field due to the loop at an axial point ( 5 mathrm{cm} ) away from the centre. | 12 |

352 | 24. The correct value of dip at a place is 45°. If the dip circle 15 rotated 45° out of the magnetic meridian then the tangent of the angle of the apparent dip is (a) 1 (b) (c) 2 | 12 |

353 | The ( _{–}-_{-}-_{-}- ) drawn at any point on the magnetic lines of force gives direction of magnetic field at that point. A. tangent B. perpendicular c. chord D. None | 12 |

354 | Curie temperature is the temperature above which A. a ferromagnetic material becomes paramagnetic B. a paramagnetic material becomes diamagnetic C . a ferromagnetic material becomes diamagnetic D. a paramagnetic material becomes ferromagnetic | 12 |

355 | Which of the following is not a property of magnetic lines of force? A. They neither have origin nor end. B. These lines do not intersect c. outside the magnet their direction is from north pole to south pole and inside the magnet these are from south to north pole. D. None | 12 |

356 | Define magnetic ‘declination’ and ‘dip’ at a place | 12 |

357 | What is the value of magnetic potential, at a distance of ( 1 mathrm{cm} ) from the pole, of pole strength 60 A-m? A. ( 600 mathrm{m} ) J/Am B. 600 ( mu ) /Ат c. 600 MJ/Am D. 600 KJ/Am | 12 |

358 | The shortest distance joining the magnetic poles of a magnet is known as magnetic length. A. True B. False | 12 |

359 | Find at what height ( x_{m}, ) the ball will experience the maximum attraction. A ( cdot x_{m}=frac{1}{sqrt{a}} ) B. ( x_{m}=frac{1}{sqrt{4 a}} ) c. ( _{x_{m}}=frac{1}{sqrt{2 a}} ) D. ( x_{m}=frac{2}{sqrt{a}} ) | 12 |

360 | A frog can be levitated in a magnetic field produced by a current in a vertical solenoid placed below the frog. This is possible because the body of the frog behaves as: A. paramagnetic B. diamagnetic c. ferromagnetic D. antiferromagnetic | 12 |

361 | A powerful magnet attracts A. all materials. B. only ferromagnetic materials and their ores. C. some materials and repels some other materials. D. only iron and its ores but does not repel any material. | 12 |

362 | The inherent property of all materials is A. Diamagnetism B. Paramagnetism C. Ferromagnetism D. Both a and | 12 |

363 | Is there anything that can block the effects or decrease the effect of gravity? Any experiments that tested it? Magnetism can be blocked and why not gravity? | 12 |

364 | When a superconductor is placed in a weak external magnetic field ( mathrm{H} ), and cooled below its transition temperature A. the magnetic field is ejected B. the magnetic field get magnetized c. the magnetic field strength increased D. none of the above | 12 |

365 | 45. The material of permanent magnet has (a) high retentively, low coercively (b) low retentively, high coercively (c) low retentively, low coercively (d) high retentively, high coercively | 12 |

366 | For a paramagnetic material, the dependence of the magnetic susceptibility ( chi ) on the absolute temperature T is given by A ( cdot x alpha T ) B. ( chi alpha ) constant ( times T ) c. ( chi alpha frac{1}{T} ) D. ( x= ) constant | 12 |

367 | Which of the following are best suited to make the core of a transformer? A. soft iron B. steel c. alnico D. none of these | 12 |

368 | The fields due to a bar magnet at equal distance on its axial and equatorial lines are A. Equal to each other B. The field on the axial line is double that on the equatorial line c. The field on the equatorial line is double that on the axial line D. There is no relationship between the two fields | 12 |

369 | Where on the surface of the earth is the vertical component of earth’s Magnetic field zero. | 12 |

370 | The earth’s magnetic field at some place on magnetic equator of the earth is ( 0.5 times 10^{-4} ) T. Consider the radius of the earth at that place as ( 6400 k m ) Then, magnetic dipole moment of the earth is ( boldsymbol{A} boldsymbol{m}^{2} ) ( left(mu_{0}=4 pi times 10^{-7} T m A^{-1}right) ) A ( cdot 1.31 times 10^{23} ) B. ( 1.05 times 10^{23} ) C. ( 1.15 times 10^{23} ) D. ( 1.62 times 10^{23} ) | 12 |

371 | The ratio of intensities of magnetic fields due to a short magnet in tan ( A ) and tan B position is A .2: B. 1: 2 ( c cdot 3: ) ( D cdot 1: 3 ) | 12 |

372 | Liquid oxygen remains suspended between two pole forces of a magnet because it is: A. diamagnetic B. paramagnetic c. ferromagnetic D. antiferromagnetic | 12 |

373 | A telephone cable at a place has four long straight horizontal wires carrying a current of ( 1.0 mathrm{A} ) in the same direction east to west. The earth’s magnetic field at the place is ( 0.39 mathrm{G} ), and the angle of dip is ( 35^{0} . ) The magnetic declination is nearly zero. What are the resultant magnetic fields at point ( 4.0 mathrm{cm} ) below the cable? B. 0.50 G c. 1.25 G D . 2.50 G | 12 |

374 | 34. A magnet is cut into four equal parts by cutting it parallel to its length. What will be the time period of each part, if the time period of the original magnet in the same field is To? (b) R$ + (d) 4T, | 12 |

375 | Assertion When diamagnetic material is placed in a non-uniform magnetic field, it tends to move from stronger to the weaker part of the magnetic field. Reason Diamagnetic materials posses string magnetism. 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 |

376 | Let the magnetic field on earth be modelled by that of a point magnetic dipole at the centre of earth. The angle of dip at a point on the geographical equator is A. always zero B. positive, negative or zero c. unbounded D. always negative | 12 |

377 | A magnet makes 40 oscillations per minute at a place having magnetic field intensity of ( 0.1 times 10^{-5} ) T. At another place, it takes 2.5 seconds to complete one vibration. The value of earth’s horizontal field at that place is A . ( 0.25 times 10^{-6} mathrm{T} ) в. 0.36 ( times 10^{-6} ) т c. ( 0.66 times 10^{-8} mathrm{T} ) D . 1.2 ( times 10^{-6} ) न | 12 |

378 | The length of a magnet is large compared to its width and breadth. The time period of its oscillation in an aberration magnetometer is 2 s. The magnet is cut along its length into three equal parts, which are then placed on each other with their like poles together. The time period of this combination will be (a) 2 s (b) 2/3 s (c) 2/3 s (d) 2/13 s (AIEEE 2004) | 12 |

379 | Two isolated point poles of strength ( 30 A m^{2} ) and ( 60 A m^{2} ) are placed at a distance of 0.3 m. The force of repulsion is: A ( cdot 2 times 10^{-3} N ) B . ( 2 times 10^{-4} N ) C ( .2 times 10^{5} N ) D. ( 2 times 10^{-5} N ) | 12 |

380 | The angle of dip at equator is : A ( cdot 0^{circ} ) B . ( 45^{circ} ) ( c cdot 60^{circ} ) D. ( 90^{circ} ) | 12 |

381 | Mark the incorrect statement. A. The direction of the magnetic field is taken to be the direction in which a north pole of the compass needle moves inside it. B. The magnetic field lines are closed curves. C. No two field-lines are found to cross each other. D. None | 12 |

382 | 25. The plane of dip circle is set in the geographic meridian and the apparent dip is e. It is then set in a vertical plane perpendicular to the geographic meridian. Now, the apparent dipis ,. The angle of declination at that place is (a) tan a = tane, tane, (b) tana = (tane, )2 + (tan ) tane, (c) tana = tane tane (d) tana = tane | 12 |

383 | An electron moving along a horizontal line with respect to the observer and towards the north. Due to each magnetic field, it deflects towards the east then position observer: A . In NHS B. In SHS c. At Equator D. None | 12 |

384 | A wire is bent in the form of an equilateral triangle of side ( 100 mathrm{cm} ) and carries a current of ( 2 A . ) It is placed in the magnetic field of induction ( 2.0 T ) directed perpendicular to the plane of the paper. The direction and magnitude of the magnetic force acting on each side of the triangle will be. A. ( 2 N ) normal to the side towards centre of the triangle B. ( 2 N ) normal to the side away from the centre of the triangle c. ( 4 N ) normal to the side towards centre of the triangle D. None of these | 12 |

385 | The incorrect statement regarding the lines of force of the magnetic field B is: A. magnetic intensity is a measure of lines of force passing through unit area held normal to it. B. magnetic lines of force form a closed curve. C. inside a magnet, its magnetic lines of force move from north pole of a magnet towards its south pole. D. magnetic lines of force never cut each other. | 12 |

386 | A magnet is placed in earth’s magnetic field with south pole of the magnet pointing north. At the neutral point This question has multiple correct options A. The earth’s magnetic field is zero B. The fields of the magnet and the earth are equal and in opposite direction C. The magnet’s magnetic field is zero D. The net magnetic field is zero | 12 |

387 | Which of the following is represented by the area enclosed by a hysteresis loop (B-H curve)? A. Permeability B. Retentivity c. Heat energy lost per unit volume in the sample D. susceptibility | 12 |

388 | Which of the following does earth’s magnetic field deflect coming from outersphere? A. Gas atoms B. Radioactive isotopes c. charged particles D. Ozone molecules | 12 |

389 | A conducting rod of length ( l ) and mass ( m ) is moving down a smooth inclined plane of inclination ( theta ) with constant velocity ( v . A ) current ( i ) is flowing in the conductor in a direction perpendicular to paper inwards, a vertically upwards magnetic field ( B ) exists in space. Then magnitude of magnetic field ( B ) is : A. ( frac{m g}{i l} sin theta ) в. ( frac{m g}{i l} tan theta ) c. ( frac{m g cos theta}{i l} ) D. ( frac{m g}{text {ilsint}} ) | 12 |

390 | Two short magnets of equal dipole moments ( M ) are fastened perpendicularly at their centres as given in the figure. The magnitude of the magnetic field at a distance ( d ) from the centre on the bisector of the right angle is A. ( frac{mu_{0} m}{4 pi d^{3}} ) в. ( frac{mu_{0} sqrt{2} M}{4 pi d^{3}} ) c. ( frac{mu_{0} 2 sqrt{2} M}{4 pi d^{3}} ) D. ( frac{mu_{0} 2 M}{4 pi d^{3}} ) | 12 |

391 | 10 The x-1/T graph for an alloy of Y paramagnetic nature is shown 0.4 — in the figure. The curie constant 03 is, then 0.2 (a) 57 K (b) 2.8 x 10-‘K 0.1 (c) 570 K 0 2 4 6 7 (d) 17.5 x 10-‘K 1/T(in 10-3 K-) Which of the following is true | 12 |

392 | A short bar magnet has a magnetic moment of ( 0.65 mathrm{JT}^{-1} ), then the magnitude and direction of the magnetic field produced by the magnet at a distance ( 8 mathrm{cm} ) from the centre of magnet on the axis is: A ( cdot 2.5 times 10^{-4} T, ) along NS direction B . 2.5 times ( 10^{-4} T ), along SN direction c. ( 4.5 times 10^{-4} T ), along NS direction D. 4.5 times ( 10^{-4} T ), along SN direction | 12 |

393 | Choose the correct statement about the properties of magnetic lines of forces. A. Lines of force are not imaginary lines B. Lines of force cannot be mapped on paper c. Lines of force do not intersect each other D. Lines of force always intersect each other | 12 |

394 | A wheel with 8 metallic spokes each 50 ( mathrm{cm} ) long is rotated with a speed of 120 rev/min in a plane normal to the horizontal component of the Earth’s magnetic field. The Earth’s magnetic field at the place is ( 0.4 mathrm{G} ) and the angle of ( 60^{circ} ).Calculate the emf induced between the axle and the rim of the wheel.How will the value of emf be affected if the number of spokes were increased? | 12 |

395 | Out of soft iron and steel which has more coercivity, less retentivity. A . iron B. steel c. both are equal D. can’t say | 12 |

396 | What are ¡) Magnetic declination ii) Magnetic dip iii) Horizontal component of earth’s magnetic field at a place? | 12 |

397 | Statement-1: The core of the transformer is laminated to avoid loss of energy. Statement-2: A laminated metal sheet placed in a changing magnetic field has lower eddy current. A. Statement-1 is true, statement-2 is true and statement-2 is NOT the correct explanation for statement-1. B. Statement-! is true, statement-2 is false c. Statement-1 is true, statement-2 is true and statement-2 is correct explanation for statement- – D. Statement-1 is false, statement-2 is true | 12 |

398 | A conductor behave as a super conductor A. Above critical temperature B. At critical temperature c. ( operatorname{At} 100^{circ} C ) D. At boiling point of that metal | 12 |

399 | The magnetic field existing in a region is given by ( overrightarrow{boldsymbol{B}}=boldsymbol{B}_{0}left(1+frac{boldsymbol{x}}{boldsymbol{l}}right) hat{boldsymbol{k}} ) A square loop of edge I and carrying a current i, is placed with its edges parallel to the ( X ) -Y axes, Find the magnitude of the net magnetic force experienced by the loop. | 12 |

400 | A freely suspended magnetic needle will always come to rest in which direction? A. north-east direction B. north-west direction c. north-south direction D. south-west direction | 12 |

401 | The angle between magnetic meridian and geographical meridian is known as: A. magnetic dip B. magnetic latitude C. magnetic declination D. magnetic longitude | 12 |

402 | Assertion Magnetic force is always perpendicular to the magnetic field. Reason Electric force is along the direction of electric 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. Both Assertion and Reason are incorrect | 12 |

403 | A magnetic substance is kept in a magnetic field, it will be thrown out of the field if it is a substance. A. paramagnetic B. ferromagnetic c. diamagnetic D. antiferromagnetic | 12 |

404 | An electron having mass ‘ ( m ) ‘ charge ‘ ( q^{prime} ) and ( K . E . K ) enters a uniform magnetic field – ‘ ( B ) ‘ perpendicularly. Then its frequency of rotation. A ( cdot frac{q B}{pi m} ) в. ( frac{q B}{2 pi m} ) с. ( frac{q B E}{2 pi m} ) D. ( frac{q B}{2 pi} ) | 12 |

405 | The B-H curve (i) and (ii) shown in the given figure is associated with A . (i) diamagnetic and (ii) paramagnetic substance B. (i) paramagnetic and (ii) ferromagnetic substance ( c . ) (i) soft iron (ii) stee D. (i) steel and (ii) soft iron | 12 |

406 | toppr 5 ( Q ) туре уоиг question and ( B_{2} ) (dashed line). If ( B_{2} ) is larger thar ( B_{1}, ) which of the following graphs shows the correct variation of ( mathrm{R} ) and ( mathrm{T} ) in these fields? | 12 |

407 | The susceptibility of a diamagnetic substance is ( A cdot infty ) B. zero c. small but negative D. small but positive | 12 |

408 | Which of the following is true regarding dimagnetic substances (symbols have their usual meaning)? ( mathbf{A} cdot mu_{r}>1, chi_{m}>1 ) B ( cdot mu_{r}>1, chi_{m}<1 ) ( mathbf{c} cdot mu_{r}<1, chi_{m}<0 ) D. ( mu_{r}0 ) | 12 |

409 | At a certain location in Africa, compass points ( 12^{circ} ) west of geographic north. The north tip of magnetic needle of a dip circle placed in the plane of magnetic meridian points ( 60^{circ} ) above the horizontal. The horizontal component of earth’s field is measured to be ( 0.16 mathrm{G} ) The magnitude of earth’s field at the location is? A. 0.32 G B. 0.42 G c. ( 4.2 mathrm{G} ) D. 3.2G | 12 |

410 | Core of electromagnets are made of ferromagnetic material which have A. low permeability and low retentivity B. high permeability and high retentivity c. high permeability and low retentivity D. low permeability and high retentivity | 12 |

411 | A domain in ferromagnetic iron is in the form of a cube of side length ( 2 mu m ) then the number of iron atoms in the domain are (Molecular mass of iron ( =mathbf{5 5 g} ) ( m o l^{-1} ) and density ( =7.92 g c m^{-3} ) ) A ( cdot 6.92 times 10^{12} ) atoms B. ( 6.92 times 10^{11} ) atoms c. ( 6.92 times 10^{10} ) atoms D. ( 6.92 times 10^{13} ) atoms | 12 |

412 | State whether true or false. Magnetic lines of force are imaginary lines. A. True B. False | 12 |

413 | A diamagnetic substance produces a A. Strong magnetic field in opposition of an externally applied magnetic field B. Weak magnetic field in the direction of an externally applied magnetic field C. Weak magnetic field in opposition of an externally applied magnetic field D. Strong magnetic field in the direction of an externally applied magnetic field | 12 |

414 | A N-pole of a very long magnetic needle is placed at a distance of ( 20 mathrm{cm} ) from a point P. If the pole strength of the magnetic needle is ( 40 mathrm{Am} ), the magnetic induction at the point ( mathrm{P} ) is ( mathbf{A} cdot 10^{-3} mathbf{T} ) B . ( 10^{-4} mathrm{T} ) ( mathbf{c} cdot 10^{-6} mathbf{T} ) D. ( 10^{-8} ) T | 12 |

415 | If horizontal and vertical component of earth’s magnetic field are equal to a certain place, the angle of dip is: ( A cdot 90^{circ} ) B . ( 45^{circ} ) ( c cdot 60 ) ( D cdot 0^{circ} ) | 12 |

416 | The narrowest hysterisis loop is for A . cobalt stee B. almico c. soft magnetic material D. stainless steel | 12 |

417 | A rod of length L, along East west direction is dropped from a height H. If B be the magnetic field due to earth at that place and angle of dip is ( theta ), then what is the magnitude of induced emf across two ends of the rod when the rod reaches the earth. | 12 |

418 | 54. Two ferromagnetic materials X and Y have hysteresis curves of the shapes shown (see figure) (a) X and Y are suitable for making a permanent magnet as well as an electromagnet (b) X is more suitable for making a permanent magnet while Y is more suitable for making an electromagnet. (c) X is more suitable for making an electromagnet while Y is more suitable for making a permanent magnet. (d) neither X nor Y is suitable for making either a permanent magnet or an electromagnet. | 12 |

419 | Out of dia, para and ferromagnetism, the universal property of all substances is A. diamagnetism B. paramagnetism C. ferromagnetism D. antiferromagnetism | 12 |

420 | How are the field lines in a uniform magnetic field ? A . curved B. parallel equidistant straight lines c. parallel but non-equispaced straight lines D. nothing can be said. | 12 |

421 | Assertion There are two neutral points on a horizontal board when a magnet is held vertically on the board Reason At the neutral point the net magnetic field due to the magnetic and magnetic field of the earth 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. Both Assertion and Reason are incorrect | 12 |

422 | The temperature bellow which a material becomes a superconductor is called A . critical temperature B. absolute temperature c. tripple point D. none of the above | 12 |

423 | A bar magnet of pole strength ( 20 A-m ) is cut into four equal parts breadth wise. Consider the following statements A) Length becomes ( 1 / 4^{t h}, ) pole strength will be same. Intensity of magnetisation will be same B) Length becomes ( 1 / 4^{t h}, ) pole strength will be ( 1 / 4^{t h} . ) Intensity of magnetisation also becomes ( 1 / 4^{t h} ) A . A is correct B. B is correct c. Both A and B are correct D. Both A and B are false | 12 |

424 | If a particle of charge ( q ) is moving with velocity v along the z-axis and the magnetic field B is acting along ( mathbf{x} ) – axis, use the expression ( vec{F}=q(vec{v} times vec{B}) ) to find the direction of the force ( F ) acting on it. | 12 |

425 | The earth’s magnetic field at a certain place has a horizontal component of ( 0.3 G ) and total strength ( 0.5 G . ) Find angle of dip in ( tan ^{-1} ) A ( cdot delta=tan ^{-1} frac{4}{3} ) B. ( delta=tan ^{-1} frac{3}{4} ) c. ( delta=tan ^{-1} frac{5}{3} ) D. ( delta=tan ^{-1} frac{3}{5} ) | 12 |

426 | The magnetic susceptibility is negative for: A. diamagnetic material only B. paramagnetic material only C . ferromagnetic material only D. paramagnetic and ferromagnetic materials | 12 |

427 | The earth behaves as a magnet with magnetic field pointing approximately from the geographic A. North to South B. South to North c. East to west D. west to East | 12 |

428 | Magnetic field intensity of a shot magnet at a distance ( 1 mathrm{m} ). on axial line is 1 Oersted. At a distance ( 2 mathrm{m} ). on the same line the intensity in Oersted is then :- A . 0.75 B. 0.125 ( c .0 .25 ) D. 0.5 | 12 |

429 | A long straight horizontal cable carries a current of ( 2.5 mathrm{A} ) in the direction ( 10^{circ} ) south of west to ( 10^{circ} ) north of east. The magnetic meridian of the place happens to be ( 10^{circ} ) west of the geographical meridian. The earth’s magnetic field at the location is ( 0.33 mathrm{G} ) and the angle of dip is zero. Locate the line of neutral points (ignore the thickness of the cable). (At neutral points, magnetic field due to a currentcarrying cable is equal and opposite to the horizontal component of earth’s magnetic field) A. ( 15.15 mathrm{mm} ) B . ( 30.15 mathrm{mm} ) c. ( 35.15 mathrm{mm} ) D. ( 40.15 mathrm{mm} ) | 12 |

430 | The angle of dip is the angle between: A. the vertical component of earth’s magnetic field and magnetic meridian B. the vertical component of earth’s magnetic field and geographical meridian C . earth’s magnetic field direction and horizontal direction D. the magnetic meridian and the geographic meridian | 12 |

431 | A frog is levitated in magnetic field produced by current in a vertical solenoid below the frog is: A. Diamagnetic B. Paramagnetic c. Ferromagnetic D. non-magnetic | 12 |

432 | 12. The relative permeability and permeability of a material are er and Hp, respectively. Which of the following values of these quantities are allowed for a diamagnetic material? (a) E, = 0.5, , = 0.5 (b) e, = 1.5, , = 1.5 (c) &, = 0.5, H, = 1.5 (d) €, = 1.5, H, = 0.5 (AIEEE 2008) | 12 |

433 | A magnetic needle free to rotate in a vertical plane parallel to the magnetic meridian has its north tip pointing down at ( 22^{underline{0}} ) with the horizontal. The horizontal component of the earth’s magnetic field at the place is known to be 0.35 G. Determine the magnitude of the earth’s magnetic field at the place. | 12 |

434 | A short bar magnet placed in a horizontal plane has its axis aligned along the magnetic north-south direction. Null points are found on the axis of the magnet at ( 14 mathrm{cm} ) from the centre of the magnet. The earth’s magnetic field at the place is ( 0.36 mathrm{G} ) and the angle of dip is zero.What is the total magnetic field on the normal bisector of the magnet at the same distance as the null-point (i.e., ( 14 mathrm{cm} ) ) from the centre of the magnet? (At null points, field due to a magnet is equal and opposite to the horizontal component of earth’s magnetic field.) | 12 |

435 | A copper ring is suspended by a thread in a vertical plane. If one end of a magnet is brought horizontally towards the ring in plane of ring as shown, the ring will B. not change its position c. move away from the magnet. D. first move towards and then move away from the magnet | 12 |

436 | A South pole and North pole of each strength ‘m’ are placed at the two corners of an equilateral triangle of side ‘a’. The resultant magnetic induction field strength at the third vertex is : A. o (zero) в. ( frac{2 mu_{0}}{4 pi} frac{m}{d^{2}} ) c. ( frac{mu_{0}}{4 pi} frac{m}{d^{2}} ) D. ( frac{3 mu_{0}}{4 pi} frac{m}{d^{2}} ) | 12 |

437 | The vertical component of the earth’s magnetic field is zero at a place where the angle of the dip is : A ( cdot 0^{circ} ) B . ( 45^{circ} ) ( c cdot 60^{circ} ) D. ( 90^{circ} ) | 12 |

438 | Assertion A current continues to flow in superconducting coil even after switch is off. Reason Superconducting coils show Meissner effect 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 |

439 | 36. Which of the following relation is correct in magnetism? (a) 1 = V2 + H2 (b) I = V+H (c) V=1+ H2 (d) V2 = 1 + H2 | 12 |

440 | Identify the correctly matched pair: A. Material – Diamagnetic Example – Gadolinium B. Material – Soft ferromagneti Example – Alnico C. Material – Hard ferromagneti Example – Copper D. Material – Paramagnetic Example -Sodium E. Material – Permanent magnet Example – Aluminium | 12 |

441 | A long straight wire (radius ( =3.0 mathrm{mm}) ) carries a constant current distributed uniformly over a cross section perpendicular to the axis of the wire. If the current density is ( 100 mathrm{A} / mathrm{m}^{2} ). The magnitudes of the magnetic field at (a) 2.0mm from the axis of the wire and 4.0 mm from the axis of the wire is A. ( 1.4 e-7 T ) B . ( 4 pi times 10^{-8} mathrm{T}, frac{pi}{2} times 10^{-8} mathrm{T} ) C ( cdot 4 pi times 10^{-8} mathrm{T}, frac{9 pi}{2} times 10^{-8} mathrm{T} ) D・ ( pi 10^{-4} mathrm{T}, frac{9 pi}{2} times 10^{-8} mathrm{T} ) | 12 |

442 | A paramagnetic liquid is taken in a Utube and arranged so that one of its limbs is kept between pole pieces of the magnet. The liquid level in the limb is A. goes down B. rises up c. remains same D. first goes down and then rise | 12 |

443 | ( chi_{1} ) and ( chi_{2} ) are susceptibilities of ( a ) diamagnetic substance at temperatures ( T_{1} K ) and ( T_{2} K ) respectively, then, A ( cdot chi_{1} T_{1}=chi_{2} T_{2} ) B . ( x_{1}=x_{2} ) c. ( chi_{1} sqrt{T_{1}}=chi_{2} sqrt{T_{2}} ) D. ( chi_{1} T_{2}=chi_{2} T_{1} ) | 12 |

444 | Column II gives approximate values of magnetic field due to source given in column I | 12 |

445 | The substance used for preparing electro magnets is : A. soft iron B. steel c. nickel D. copper | 12 |

446 | Which of the following does earth’s magnetic field deflect coming from outersphere? A. Gas atoms B. Radioactive isotopes c. charged particles D. Ozone molecules | 12 |

447 | A uniform magnetic field parallel to the plane of paper, existed in space initially directed from left to right. When a bar of soft iron is placed in the field parallel to it, the lines of force passing through it will be represented by figure. ( mathbf{A} ) B. ( c ) D. | 12 |

448 | The force between two magnetic poles is ( F ) when they are separated by certain distance. If the distance between the two poles is doubled and strength of each pole is tripled. The percentage change in the force between the two poles is : A. ( 125 % ) B. ( 100 % ) c. ( 50 % ) D. ( 25 % ) | 12 |

449 | A magnetic needle suspended horizontally by an unspun silk fibre oscillates in the horizontal plane, because of the restoring force originating mainly from A. the torsion of the silk fibre B. the horizontal component of earth’s magnetic field c. the force of gravity D. all of the above | 12 |

450 | 4. The magnetic lines of force inside a bar magnet (a) are from the south pole to the north pole of the magnet (b) are from the north pole to the south pole of the magnet (c) do not exist (d) depend upon the area of cross-section of the bar magnet (AIEEE 2003) | 12 |

451 | Domain formation is the necessary feature of A. ferro magnetism B. paramagnetism c. diamagnetism D. electro magnetism | 12 |

452 | Which of the following property shows the property of ferromagnetic substances? A. The ferromagnetic property depends on temperature B. The ferromagnetic property does not depend on temperature. c. At high enough temperature ferromagnet becomes a diamagnet D. At low temperature ferromagnet becomes a paramagnet | 12 |

453 | A superconductor has ( T_{c}(0)=100 K ) When a magnetic field of 7.5 T is applied, its ( T_{c} ) decreases to 75 K. For this material one can definitely say that when A ( cdot B=5 T, T_{c}(B)=80 K ) В. ( B=5 T, 75 K<T_{c}(B)<100 K ) C . ( B=10 T, 75 K<T_{c}(B)<100 K ) D. ( B=10 T, T_{c}=70 K ) | 12 |

454 | The north poles of pole strengths, ( boldsymbol{m}, boldsymbol{9} boldsymbol{m} ) are kept apart by certain distance ‘ ( boldsymbol{d} ) Find distance of null point from larger pole A ( .2 d / 4 ) в. ( 2 d / 3 ) c. ( 5 d / ) D. ( 3 d / 2 ) | 12 |

455 | Compare paramagnetism and ferro magnetism. Give examples of each. | 12 |

456 | The ( chi-left(frac{1}{T}right) ) graph for an alloy of paramagnetic nature is shown in figure The curie constant is, then ( A cdot 57 K ) B . ( 2.8 times 10^{-3} K ) c. ( 570 K ) D. ( 17.5 times 10^{-3} K ) | 12 |

457 | A thin straight vertical conductor has 10amp current flows vertically upwards. It is present at a place where ( B_{H}=4 times 10^{-6} T . ) At which point magnetic feild will be maximum A. ( 0.5 m ) on south of conductor B. ( 0.5 m ) on west of conductor ( mathrm{c} .0 .5 mathrm{m} ) on east of conductor D. ( 0.5 m ) on north-east of conductor | 12 |

458 | Two short bar magnets with magnetic moments ( 8 A m^{2} ) and ( 27 A m^{2} ) are placed ( 35 mathrm{cm} ) apart along their common axial line with their like poles facing each other. The neutral point is : A. in midway between them B. ( 21 mathrm{cm} ) from weaker magnet c. ( 14 mathrm{cm} ) from weaker magnet D. ( 27 mathrm{cm} ) from weaker magnet | 12 |

459 | The distance between the poles of a horse shoe magnet is ( 0.1 mathrm{m} ) and its pole strength is ( 0.01 mathrm{A} ) -m. The induction of magnetic field at a point mid way between the poles will be : A. zero В. ( 2 times 10^{-5} T ) C ( .4 times 10^{-6} T ) D. ( 8 times 10^{-7} T ) | 12 |

460 | 73. The magnet of vibration magnetometer is heated so as to reduce its magnetic moment by 36%. By doing this the periodic time of the magnetometer will (a) increases by 36% (b) increases by 25% (c) decreases by 25% (d) decreases by 64% | 12 |

461 | Are the magnetic field lines closed? Explain. | 12 |

462 | At a given place on the earth’s surface, the horizontal component of earth’s magnetic field is ( 3 times 10^{-6} T ) and resultant magnetic field is ( 6 times 10^{-6} T ) Angle of dip at this place is : A . ( 30^{circ} ) B . ( 40^{circ} ) ( c cdot 50^{circ} ) D. ( 60^{circ} ) | 12 |

463 | When magnetic field at ( mathrm{P} ) and ( mathrm{Q} ) is same then OP/OQ is: A ( cdot frac{1}{3} ) B. ( frac{1}{frac{1}{3}} ) ( c cdot 2 sqrt{2} ) D. ( frac{3}{2} ) | 12 |

464 | Column I shows different positions in which one pole of a magnet is placed near that of the other. Column II indicates the resulting action between them for each situation. Fill in the blanks. Column I || ( N-N ) Attraction ( s-1 ) Repulsion | 12 |

465 | Which of the following group is diamagnetic? A. Copper, hydrogen, silver B. Copper, hydrogen, argon c. Hydrogen, oxygen, argon D. Copper, silver, oxygen | 12 |

466 | A magnet has coercivity of ( 3 times 10^{3} ) ( A m^{-1} . ) It is kept in a ( 10 mathrm{cm} ) long solenoid with a total of 50 turns. How much current has to be passed through the solenoid to demagnetize it? | 12 |

467 | At the centre of which of the following four circular rings is the magnetic field strongest, for equal magnitude of current? A . 3 B. ( c cdot 4 ) ( D ) | 12 |

468 | Define magnetic declination. | 12 |

469 | Two identical short magnets having magnetic moment M are placed perpendicular to each other centres coinciding as shown in adjacent figure. The magnitude of the magnetic field at a point ( P ) at angle distance ‘d’ on the bisector of right angle will be : A. ( frac{sqrt{2} mu_{0} M}{4 pi d^{3}} ) B. ( frac{2 sqrt{2} mu_{0} M}{4 pi d^{3}} ) c. ( frac{2 mu_{0} M}{4 pi d^{3}} ) D. ( frac{sqrt{3} mu_{0} M}{4 pi d^{3}} ) | 12 |

470 | The horizontal and vertical components of earth’s magnetic field at a place are ( 0.3 G ) and ( 0.52 G . ) The earth’s magnetic field and the angle of dip are A ( cdot 0.3 mathrm{G} ) and ( rho=30^{circ} ) B. 0.4G and ( rho=40^{circ} ) c. ( 0.5 mathrm{G} ) and ( rho=50^{circ} ) D. ( 0.6 mathrm{G} ) and ( rho=60^{circ} ) | 12 |

471 | The period of osillation of a freely suspended bar magnet is 4 second. If it is cut into two equal parts in length, then the time period of each part will be A. 4 sec B. 2sec c. ( 0.5 s e c ) D. 0.25 sec | 12 |

472 | 10. Needles Ni, N2, and Nz are made of ferromagnetic, paramagnetic, and diamagnetic substances, respectively. A magnet when brought close to them will (a) attract N, strongly, but repel N2 and Nz weakly (b) attracts all three to them (c) attract N, strongly, N, weakly and repel N, weakly (d) attract N, and N2 strongly but repel N3 (AIEEE 2006) | 12 |

473 | Force acting between two small magnets, placed in end on position ( 0.1 m ) apart from their centres is (Given magnetic moment of each magnet is ( left.5 A m^{2}right) ) A . ( 0.6 N ) B. ( 0.8 N ) c. ( 0.15 N ) D. ( 0.2 N ) | 12 |

474 | 17. A compass needle of magnetic moment 60 Am² pointing geographical north at a place where the horizontal component of earth field is 40 u Wb m-experiences a torque of 1.2 x 10-Nm. (a) 15° (b) 30° (c) 45° (d) 60° | 12 |

475 | Calculate the magnetic field generated by n segment of an right triangle. | 12 |

476 | Distinguish between Para, Ferro and Diamagnetism. | 12 |

477 | A charged particle is moved along a magnetic field line.The magnetic force on the particle is A. opposite to its velocity B. along its velocity c. zero D. perpendicular to its velocity | 12 |

478 | Which of the following substances are para-magnetic? ( boldsymbol{B} boldsymbol{i}, boldsymbol{A l}, boldsymbol{C u}, boldsymbol{C a}, boldsymbol{P b}, boldsymbol{N i} ) | 12 |

479 | An electron makes ( 3 times 10^{5} ) revolutions per second in a circle of radius 0.5 angstrom. Find the magnetic field ( B ) at the centre of the circle. | 12 |

480 | The dip at the poles is ( mathbf{A} cdot 80 ) B. 60 c. 90 D. 0 | 12 |

481 | Answer the following questions: (a) Explain qualitatively on the basis of domain picture the irreversibility in the magnetisation curve of a ferromagnet. (b) The hysteresis loop of a soft iron piece has a much smaller area than that of a carbon steel piece. If the material is to go through repeated cycles of magnetisation, which piece will dissipate greater heat energy? (c) ‘A system displaying a hysteresis loop such as a ferromagnet, is a device for storing memory? Explain the meaning of this statement. (d) What kind of ferromagnetic material is used for coating magnetic tapes in a cassette player, or for building ‘memory stores’ in a modern computer? (e) A certain region of space is to be shielded from magnetic fields. Suggest a method. | 12 |

482 | Magnetic permeability of paramagnetic substances is? ( mathbf{A} cdot mathbf{0} ) B ( .>1 ) ( c cdot<1 ) D. | 12 |

483 | If the earth does not rotate on its axis, the change in the weight of a body at the equator would be about (Take radius of earth-6400 ( mathrm{km} ) ) A. 0.003%v larger B. 0.3% longer c. ( 0.3 % ) smaller D. 0.003% smaller | 12 |

484 | Assume the dipole model for earth’s magnetic field B which is given by thevertical component of magnetic field, ( B_{V}=frac{mu_{o}}{4 pi} frac{2 m cos theta}{r^{3}} ) and the horizontal component of magnetic field ( B_{H}=frac{mu_{o}}{4 pi} frac{m sin theta}{r^{3}}, ) where ( theta=90^{circ}- ) latitude as measured from magnetic equator, then the loci of point for which dip angle is ( pm mathbf{4 5}^{circ} ) ( mathbf{A} cdot tan ^{-1}(3) ) ( mathbf{B} cdot tan ^{-1}(2) ) ( mathbf{c} cdot tan ^{-1}(0.5) ) ( mathbf{D} cdot tan ^{-1}(1) ) | 12 |

485 | A telephone cable at a place has four long straight horizontal wires carrying a current of ( 1.0 mathrm{A} ) in the same direction east to west. The earth’s magnetic field at the place is ( 0.39 mathrm{G}, ) and the angle of dip is ( 35^{circ} ).The magnetic declination is nearly zero. What are the resultant magnetic fields at points ( 4.0 mathrm{cm} ) below the cable? | 12 |

486 | is present around the magnet. | 12 |

487 | 19. The force between two short bar magnets with magnetic moments M and M2 whose centres are r metre apart is 0.8 N when their axes are in the same line. If the separation is increased to 2r, then force between them is reduced to (a) 4.0 N (b) 2.0 N (c) 1.0 N (d) 0.5 N | 12 |

488 | A permanent magnet A. attracts all substances B. attracts only ferromagnetic substances C . attracts magnetic substances and repels all others D. attracts some substances and repels others | 12 |

489 | A very long magnet is placed vertically with one pole on the table. A neutral point was found at ( 20 mathrm{cm} ) from the pole. What is the pole strength if the vertical component of earth’s field is ( 0.4 times ) ( 10^{-4} W b m^{-2} ? ) ( mathbf{A} cdot 16 A-m ) в. ( 8 A-m ) ( mathrm{c} cdot 4 A-m ) D. None of these | 12 |

490 | The vertical component of earth’s magnetic field is zero at A. magnetic equator B. magnetic poles c. geographical poles D. everywhere | 12 |

491 | The magnetic lines of forces due to the horizontal component of Earth’s magnetic field will be A . circular B. elliptical c. curved D. horizontal and parallel | 12 |

492 | At a place on the surface of earth vertical component of earths field is two times that of horizontal component. Then the latitude angle at the place is ( mathbf{A} cdot tan ^{-1}(2) ) B cdot ( tan ^{-1}(1 / 2) ) ( c cdot 45^{circ} ) D. ( 0^{circ} ) | 12 |

493 | allo1 26. In a vibration magnetometer, the time period of a bar magnet oscillating in horizontal component of earth’s magnetic field is 2 s. When a magnet is brought near and parallel to it, the time period reduces to 1 s. The ratio H/F of the horizontal component H, and the field F due to magnet will be (a) 3 (b) 1/3 (c) 13 (d) 1/3 | 12 |

494 | Two points ( A ) and ( B ) are situated at distance ( x ) and ( 2 x ) respectively from the nearer pole of a magnet 2cm long. The ratio of magnetic field at ( A ) and ( B ) is? A. 4: 1 exactly B. 4 : 1 approximately c. 8: 1 exactly D. 8: 1 approximately | 12 |

495 | An electron enters a chamber in which a uniform magnetic field is present as shown. An electric feild of appropriate magnitude is also applied so that the electron travels undeviated without any change in its speed through the chamber. We are ignoring gravity. Then, the direction of the electric field is A. Opposite to the direction of the magnetic field. B. Opposite to the direction of the electron’s motion. C. Normal to the plane of the paper and coming out of the plane of the paper. D. Normal to the plane of the paper and into the plane of the paper. | 12 |

496 | What is the unit of ratio ( frac{E}{H} ? ) | 12 |

497 | A bar magnet has coercivity ( 4 times ) ( 10^{3} A m^{-1} . ) It is placed in a solenoid having 40 turns per ( mathrm{cm} ) and is ( 1.2 mathrm{m} ) long. The current carried by the solenoid to demagnetize the bar magnet is : ( A cdot 6 A ) в. ( 8 A ) c. ( 5.78 A ) D. none of these | 12 |

498 | Two magnetic poles of pole strengths ( 324 m A-m ) and ( 400 m A-m ) are kept at a distance of ( 10 mathrm{cm} ) in air. The null point will be at a distance of on the line joining the two poles, from the weak pole if they are like poles: A. 4.73 B. 5 ( c .6 .2 ) D. 5.27 | 12 |

499 | Which of the following is responsible for the earth’s magnetic field? A. Convective currents in earth’s core B. Diversive current in earth’s core c. Rotationa motion of earth. D. Translational motion of earth | 12 |

500 | A long straight horizontal cable carries a current of ( 2.5 mathrm{A} ) in the direction ( 10^{0} ) south of west to ( 10^{0} ) north of east. The magnetic meridian of the place happens to be ( 10^{0} ) west of the geographic meridian. The earth’s magnetic field at the location is ( 0.33 mathrm{G} ) and the angle of dip is zero. Locate the line of neutral points (ignore the thickness of the cable). (At neutral points, magnetic field due to a current carrying cable is equal and opposite to the horizontal component of earth’s magnetic field.) A. ( 15.15 mathrm{mm} ) B. ( 30.15 mathrm{mm} ) c. ( 35.15 mathrm{mm} ) D. ( 40.15 mathrm{mm} ) | 12 |

501 | Whm ( ^{-2} ) is equal to ( A cdot 10^{4} G ) B . ( 10^{2} ) G ( c cdot 10^{-2} mathrm{G} ) D. ( 10^{-4} mathrm{G} ) | 12 |

502 | 23. If the total magnetic field due to earth is 28 A/m , then the total magnetic induction due to earth is (a) 28 T (b) 280 T (c) 0.352 gauss (d) 0.352 T | 12 |

503 | The magnetic field intensity due to a bar magnet is ( 100 mathrm{Am}^{-1} ). The magnetic induction field strength due to it is: A ( cdot frac{4 pi}{10^{7}} T ) B. ( frac{4 pi}{10^{5} T} ) ( ^{mathbf{C}} cdot frac{10^{3}}{4 pi} T ) D. ( frac{10^{5}}{4 pi} T ) | 12 |

504 | If a magnet is suspended at an angle ( 30^{circ} ) to the magnetic meridian, the dip needle makes angle of ( 45^{circ} ) with the horizontal. The real dip is : A ( cdot tan ^{-1}(sqrt{3} / 2) ) B. ( tan ^{-1}(sqrt{3}) ) ( mathbf{c} cdot tan ^{-1}(sqrt{3} / sqrt{2}) ) D. ( tan ^{-1}(2 / sqrt{3}) ) | 12 |

505 | The dependence of the critical temperature for superconductivity upon A. isotopic mass B. isotonic mass c. isobaric mass D. Both A and B | 12 |

506 | Tangent law is applicable only when A. applied field is parallel to the earth’s horizontal component B. applied field is antiparallel to the earth’s horizontal component C . applied field is perpendicular the earth’s horizontal component in horizontal plane D. applied field is inclined to the earth’s horizontal component | 12 |

507 | Write three difference between diamagnetic and paramagnetic substances. | 12 |

508 | Needles ( N_{1}, N_{2} ) and ( N_{3} ) are made of a ferromagnetic, a paramagnetic and a diamagnetic substance respectively. A magnet when brought close to them will A. attract all three of them. B. attract ( mathrm{N}_{1} ) and ( mathrm{N}_{2} ) strongly but repel ( mathrm{N}_{3} ) C. attract ( mathrm{N}_{1} ) strongly, ( mathrm{N}_{2} ) weakly and repel ( mathrm{N}_{3} ) weakly D. attract ( mathrm{N}_{1} ) strongly, but repel ( mathrm{N}_{2} ) and ( mathrm{N}_{3} ) weakly | 12 |

509 | In a plane perpendicular to the magnetic meridian the dip needle will remain : A. Vertical B. Horizontal C. At an angle of ( 45^{circ} ) from horizontal D. At an angle of ( 60^{circ} ) from vertical | 12 |

510 | The needle of the dip circle of a place stay at ( 30^{0} . ) The dip circle is inclined at an angle towards ( 30^{0} ) with the magnetic meridian. The true dip at the place is: A ( cdot tan ^{-1} sqrt{3} ) B. ( tan ^{-1} frac{sqrt{3}}{2} ) c. ( tan ^{-1} frac{1}{2} ) D. ( tan ^{-1} frac{3}{2} ) | 12 |

511 | 31. A magnet needle makes 4 vibrations per second at a place where H = 3.5 x 10- T. What is the value of H at place, where the same needle makes 3 vibrations per second? (a) 1.98 x 10-T (b) 3.5 x 10-5T (c) 4.0 x 10-5T (d) 3.96 x 10-5T | 12 |

512 | Write on expression for vector from of magnetic force on a moving charge. | 12 |

513 | The angles of dip at the poles and the equator respectively are. A . ( 30^{circ}, 60^{circ} ) B . ( 0^{circ}, 90^{circ} ) c. ( 45^{circ}, 90^{circ} ) D. ( 90^{circ}, 0^{circ} ) | 12 |

514 | Define magnetic lines of force and state its two properties. | 12 |

515 | The plane of a dip circle is set in the geographical meridian and the apparent dip is ( theta_{1} ). If it is set in a vertical plane perpendicular to the geographical meridian, then the apparent dip becomes ( theta_{2} ). The angle of declination ( alpha ) at the given place is given by : A. ( tan alpha=sqrt{left(tan theta_{1} tan theta_{2}right)} ) B. ( tan alpha=frac{tan theta_{1}}{tan theta_{2}} ) ( c cdot tan alpha=tan theta_{1}+tan theta_{2} ) D. ( tan alpha=frac{tan theta_{2}}{tan theta_{1}} ) | 12 |

516 | Curie temperature is defined as the temperature above which. A. A paramagnetic material becomes ferromagnetic B. A ferromagnetic material becomes paramagnetic C. A ferromagnetic material becomes diamagnetic D. A diamagnetic material becomes ferromagnetic | 12 |

517 | The magnetic force required to demagnetise the material is A. retentivity B. coercivity c. energy loss D. hysterisis | 12 |

518 | If ( chi ) stands for the magnetic susceptibility of a substance, ( mu ) for its magnetic permeability and ( mu_{0} ) for the permeability of free space, then This question has multiple correct options A. For a paramagnetic substance: ( chi>0, mu>0 ) B. For a paramagnetic substance: ( quad chi>0, quad mu>mu_{0} ) c. For a diamagnetic substance: ( chi<0, mu1, mu<mu_{0} ) | 12 |

519 | Susceptibility is small and negative for A. para magnetio B. diamagnetic C. ferro magnetic D. electromagnetic | 12 |

520 | Susceptibility is positive and large for a A. paramagnetic substance B. ferromagntic substance c. diamagnetic substance D. non magnetic substance | 12 |

521 | Problems Based on Mixeu Concepts 55. Ata certain place, the angle of dip is 50° and the horizontal component of earth’s field is 0.15 T. A beam of protons is moving vertically upwards with a speed of 3 x 10 ms. The force on proton is [cos 50º = 0.6, sin 50º = 0.8] (a) 4.39 x 10-15 N (b) 5.88 x 10-15 N. (c) 8.60 x 10-15 N (d) 7.20 x 10-15 N The manatia field intoncitu Lot the montofle | 12 |

522 | Assertion The product of magnetic susceptibility and absolute temperature for a paramagnetic substance is constant Reason Susceptibility is positive but very small | 12 |

523 | Field lines are shown close together where the A. magnetic field is far apart B. magnetic fields is zero c. magnetic fields is greater D. all | 12 |

524 | A magnetic needle makes an angle of 45 with the thread from which it is suspended then A. Dip at that place is 45 B. Inclination at that place is 45 c. Declination angle at that place is 45 D. Both (1) and (2) | 12 |

525 | At a place on the surface of earth vertical component of earth’s field is two times that of horizontal component. Then the latitude angle at that place is ( mathbf{A} cdot tan ^{-1}(2) ) B cdot ( tan ^{-1}(1 / 2) ) ( c cdot 45^{circ} ) D. ( 0^{circ} ) | 12 |

526 | Ferromagnetic materials have their properties due to A. vacant inner subshells B. partially filled inner subshells C. filled inner subshells D. completely filled outer shells | 12 |

527 | The curie weiss law is obeyed by iron A. at all temperatures B. above the curie temperature C . below the curie temperature D. at the curie temperature | 12 |

528 | The angle of dip at a place where horizontal and vertical components of Earth’s magnetic field are equal is A ( .45^{circ} ) B. ( 30^{circ} ) ( c cdot 0^{circ} ) D. ( 60^{circ} ) E ( .90^{circ} ) | 12 |

529 | You are provided with two similar bars. One is magnet and the other is a soft iron. How will you distinguish between them without the use of any other magnet or bar? | 12 |

530 | Ferromagnetic ore properties are due to A. filled inner sub-shells B. vacant inner sub-shells C . partially filled inner sub-shells D. all the sub-shells equally filled | 12 |

531 | Two magnets are kept one above the other and made to oscillate in horizontal plane. The period combination is 6 second. When one of the magnets is reversed pole to pole, the period of oscillations of combination is 3 second. Compare the magnetic pole moments of the two magnets. | 12 |

532 | Q Type your question substance is best represented by figure ( A ) B. ( c ) ( D ) | 12 |

533 | The total number of magnetic lines of force originating or terminating on a pole of strength ( mathrm{m} ) is : A. ( frac{mu_{o} m}{4 pi} ) в. ( frac{m}{mu_{o}} ) ( c cdot m^{2} ) D. ( mu_{o} m ) | 12 |

534 | A cylindrical rod magnet has a length of ( 5.0 mathrm{cm} ) and a diameter of ( 1.0 mathrm{cm} . ) It has a uniform magnetization of ( 5.3^{*} 10^{3} mathrm{A} / mathrm{m} ) What is its magnetic dipole moment? A . 20.8 ( m J T^{-1} ) B . ( 10.8 m J T^{-1} ) ( mathbf{c} cdot 5.8 m J T^{-1} ) D. 30.8mJT” | 12 |

535 | (a) State Gauss’ law for magnetism. (b) How this differs from Gauss’ law for electrostatics? (c) Why is the difference in the two cases? | 12 |

536 | A magnet of dipole moment ( 2 A m^{2} ) is deflected through ( 30^{circ} ) from magnetic meridian. The required deflecting torque is ( left(B_{H}=0.4 times 10^{-4} Tright) ) A ( cdot 0.4 times 10^{-4} mathrm{Nm} ) B. ( 0.4 mathrm{Nm} ) c. ( 0.2 times 10^{-4} N m ) D. None of these | 12 |

537 | ( t ) | 12 |

538 | Find the interaction force of two coils with magnetic moments ( boldsymbol{p}_{1 m}=mathbf{4 . 0} boldsymbol{m} boldsymbol{A} ) ( -m^{2} ) and ( p_{2 m}=6.0 m A-m^{2} ) and collinear axes if the separation between the coils is equal to ( l=20 mathrm{cm} ) which exceeds considerably their linear dimensions. A . 9 B. 5 c. 8 D. 10 | 12 |

539 | Two small bar magnets are placed in a line at certain distance ( d ) part. If the length of each magnet is negligible compared to ( d ), the force between them will be inversely proportional to: ( mathbf{A} cdot d^{2} ) B. ( d ) ( c cdot d^{3} ) D. ( d^{4} ) | 12 |

540 | Which part has maximum attraction in a magnet? A. In the centre B. on the sides c. on the poles D. on the surface | 12 |

541 | Define transition temperature. | 12 |

542 | 40. If a magnetis suspended at an angle 30 to the magnet meridian, it makes an angle of 45′ with the horizontal The real dip is (a) tan(13/2) (b) tan (13) (e) tan(3/2) (d) tan (2/13) | 12 |

543 | 16. Hysteresis loops for two magnetic materials A and B are given below: →H – H (A) (B) These materials are used to make magnets for electric generators, transformer core and electromagnet core. Then it is proper to use (a) A for electric generators and transformers (b) A for electromagnets and B for electric generators (c) A for transformers and B for electric generators (d) B for electromagnets and transformers (JEE Main 2016) | 12 |

544 | Assertion: The properties of paramagnetic and ferromagnetic substances are not affected by heating. Reason: As temperature rises, the alignment of molecular magnets gradually decreases A. Both A and R are true and R is the correct explanation of A B. Both A and R are true and R is not correct explanation of A c. A is true, but R is false D. A is false, but R is true | 12 |

545 | Assertion Ferro-magnetic substances become paramegnetic above Curie temp Reason Domains are destroyed at high | 12 |

546 | What is hysteresis? Define the terms ‘coercivity’ and ‘retentivity’ of a ferromagnetic material. | 12 |

547 | 29. Two bar magnets of the same mass, same length and breadth but having magnetic moments M and 2M are joined together pole for pole and suspended by a string. The time period of assembly in a magnetic field of strength Hy is 3 seconds. If now the polarity of one of the magnets is reversed and the combination is again made to oscillate in the same field, the time of oscillation is (a) V3 (e) 3 (d) 6 (b) 3V3 | 12 |

548 | At Curie temperature, in ferromagnetic materials A. the atomic dipoles get aligned B. the atomic dipoles remains stationary C. the atomic dipoles lose alignment D. magnetism is zero | 12 |

549 | Assertion: Paramagnetic substances get weakly attracted to a magnet. Reason : They have tendency to move from a region of strong magnetic field to weak magnetic field A. If both assertion and reason are true and reason is the correct explanation of assertion. B. If both assertion and reason are true and reason is not the correct explanation of assertion c. If assertion is true but reason is false D. If both assertion and reason are false | 12 |

550 | toppr -०६॥ Q Type your question_ placed the ends ( (X text { and } Y) ) of each object, near the north pole of the bar magnet and recorded his observations in the table below. End Y brought End X Object brought near near to N pole to N pole N pole repelled ( quad ) N pole attracted ” N pole attracted ( quad ) N pole repelled ( begin{array}{ll}text { N pole } & text { N pole remains } \ text { remains } & text { stationary } \ text { stationary } & end{array} ) Which of the object(s) is/are the magnet? Bar magnet Object A. P only ( c ) D. P and R only | 12 |

551 | 65. A magnetic dipole is under the effect of two magn fields inclined at 75° to each other. One of the fields a magnitude of 1.5 x 10°-T. The magnets come to stable position at an angle of 30° with the direction of the al field. The magnitude of other field is (a) 1.5 x10-21 (b) x10-2T 25×10 (c) 1.5x 12 x10-21 (d) 1.5×10-2T | 12 |

552 | A magnetic field exists in the region surrounding a magnet, in which the force of the magnet can be detected. Is the given statement true or false? | 12 |

553 | The lines of force of a bar magnet are: A. Parallel and straight B. Concentric circles c. Curved lines D. Curved closed loops | 12 |

554 | A compass needle whose magnetic moment is ( 60 A m^{2} ) pointing geographical north at a certain place where the horizontal component of earth’s magnetic field is ( 40 times 10^{-6} mathrm{Wb} ) ( m^{-2} ) experiences a torque of ( 1.2 times 10^{-3} ) N m. The declination of the place is? A ( cdot 20^{circ} ) B . ( 45^{circ} ) ( c cdot 60^{circ} ) D. ( 30^{circ} ) | 12 |

555 | Angle of dip ( delta ) and latitude ( lambda ), on earth’s surface are related as ( mathbf{A} cdot tan delta=2 tan lambda ) B. ( tan delta=cot lambda ) ( mathbf{C} cdot tan delta=frac{tan lambda}{2} ) D. ( tan delta=tan lambda ) | 12 |

556 | Few iron nails and screws got mixed with wood shavings while a carpenter was working with them. How can you help him in getting the nails and screws back from the scrap without wasting his time by searching with his hands? | 12 |

557 | A thin rectangular magnet suspended freely has a period of oscillation equal to T. Now it is broken into two equal halves (each having half of the original length) and one piece is made to oscillate freely in the same field. If its period of oscillation is T’, the ratio T/T is 1 (b) 212 (d) 2 (AIEEE 2003) | 12 |

558 | Above Curie temperature, ferromagnetic substances become A. diamagnetic B. paramagnetic c. ferrimagnetic D. none of these | 12 |

559 | The corecivity of a small magnet where the ferromagnet gets demagnetized is ( 3 times 10^{3} A m^{-1} . ) The current required to be passed in a solenoid of length ( 10 mathrm{cm} ) and number of turns ( 100, ) so that the magnet gets demagnetized when inside the solenoid is: ( A cdot 3 A ) в. ( 6 A ) ( c .30 m A ) D. ( 60 m A ) | 12 |

560 | The correct value of dip angle at a place is ( 45^{circ} . ) If the dip circle is rotated by ( 45^{circ} ) out of the meridian, then the tangent of the angle of apparent dip at the place is A . 1 B. ( 1 / 2 ) c. ( 1 / sqrt{2} ) D. ( sqrt{2} ) | 12 |

561 | At a given place on earth’s surface the horizontal component of earths magnetic field is ( 2 times 10^{-5} mathrm{T} ) and resultant magnetic field is ( 4 times 10^{-5} mathrm{T} ) The angle of dip at this place is? A . ( 30^{circ} ) B. ( 60^{circ} ) ( c cdot 90^{circ} ) D. ( 45^{circ} ) | 12 |

562 | Needles ( N_{1}, N_{2}, N_{3} ) are made of a ferromagnetic, a paramagnetic and a diamagnetic substance respectively. A magnet when brought close to them will: A. attract ( N_{1} ) and ( N_{2} ) strongly but repel ( N_{3} ) B. attract ( N_{1} ) strongly, ( N_{2} ) weakly and repel ( N_{3} ) weakly C. attract ( N_{1} ) strongly, but repel ( N_{2} ) and ( N_{3} ) weakly D. attract all three of them | 12 |

563 | Assertion Magnetic field interacts with a moving charge and not with a stationary charge. Reason A moving charge produces a magnetic field. | 12 |

564 | Permanent magnets are made from A. diamagnetic substances B. paramagnetic substance C. ferromagnetic substances D. wood | 12 |

565 | Needles ( N_{1}, N_{2} ) and ( N_{3} ) are made of a ferromagnetic, a paramagnetic and a diamagnetic substance respectively. A magnet when brought close to them will? A. Attract all three of them B. Attract ( N_{1} ) strongly, ( N_{2} ) weakly and repel ( N_{3} ) weakly C. Attract ( N_{1} ) strongly but repel ( N_{2} ) and ( N_{3} ) weakly D. Attract ( N_{1} ) and ( N_{2} ) strongly but repel ( N_{3} ) | 12 |

566 | State and explain Curie’s law. | 12 |

567 | Among which the magnetic susceptibility does not depend on the temperature? A. Dia-magnetism B. Para-magnetism c. Ferro-magnetism D. Ferrite | 12 |

568 | At what distance on the axis, from the centre of a circular current carrying coil of radius ( r, ) the magnetic field becomes 1/8th of the magnetic field at centre? A ( cdot sqrt{2} r ) B ( cdot 2^{3 / 2} ) ( c cdot r sqrt{3} ) D. ( 3 sqrt{2} r ) | 12 |

569 | Assertion Diamagnetism is universal, it is present in all materials. Reason Field due to induced magnetic moment is opposite to the magnetising 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. Both Assertion and Reason are incorrect | 12 |

570 | The force between two magnetic poles reduces to ( a N, ) if distance between them is increased to ( n ) times and it increases to ( b N ) if the distance between them is ( 1 / n^{t h} ) the original value. Then ( a: b ) is : ( A cdot 1 cdot n^{2} ) B ( cdot n^{2}: ) ( c cdot n^{4} cdot 1 ) ( D cdot 1: n^{4} ) | 12 |

571 | If the bar magnet is turned around by ( 180^{circ}, ) where will the new null points be located? | 12 |

572 | Out of the two magnetic materials, ‘A’ has relative permeability slightly greater than unity while ‘B’ has less than unity. Identify the nature of the materials ‘A’ and ‘B’. Will their susceptibilities be positive or negative? | 12 |

573 | (c) 7.54 Am 69. An iron rod of volume 10m and relative permeability 1000 is placed inside a long solenoid wound with 5 turns/cm. If a current of 0.5 A is passed through the solenoid, then the magnetic moment of the rod is (a) 10 Am (b) 15 Am (c) 20 Am? (d) 25 Am not be cercivity y 103 Am-1 It is de – A 1 | 12 |

574 | Two circular coils each of 100 turns are held such that one lies in the vertical plane and the other in the horizontal plane with their centres coinciding. The radius of vertical and horizontal coils are ( 20 mathrm{cm} ) and ( 30 mathrm{cm} ) respectively. If the magnetic field at their common centre is zero, find current in each coil Horizontal component of earth’s magnetic field is 27.8 Aim and angle of dip at this place is ( 30^{circ} ) | 12 |

575 | At a place of Earth, the vertical component of Earth’s magnetic field is ( sqrt{3} ) times its horizontal component. The angle of dip at this place is A .60 B. 30 c. 45 D. 0 | 12 |

576 | The magnets shown here will A. Attract each other B. Repel each other c. Pull each other D. cannot say | 12 |

577 | 27. The magnetic needle of an oscillation magnetometer makes 0 oscillations per minute under the action of earth’s magnetic field only. When a bar magnet is placed at some distance along the axis of the needle, it makes 14 oscillations per minute. If the bar magnet be turned so that its poles interchange the positions, the new frequency of the needle is (a) 2 oscillations per minute (b) 12 oscillations per minute (c) 20 oscillations per minute (d) 69.7 oscillations per minute | 12 |

578 | 61. A bar of mass M is suspended by two wires. Assume that a uniform magnetic field B is directed into the page. When the current through the bar is 1, then the tension in each supporting wire is (a) Mg (b) 2BIL Mg- BIL (c) Mg – BIL | 12 |

579 | When two magnetic poles having same pole strength are separated by a distance of ( 20 mathrm{cm}, ) a force of ( 5 mathrm{N} ) acts between them. If the distance is halved, the force becomes A . 20 N B. 10 N ( c .15 mathrm{N} ) D. 25 N | 12 |

580 | At a place the value of ( B_{H} ) and ( B_{V} ) are ( 0.4 times 10^{-4} ) and ( 0.3 times 10^{-4} ) respectively. The resultant earths magnetic field is : A ( .0 .5 times 10^{-4} T ) в. ( 10^{-4} T ) c. ( 2 times 10^{-4} T ) D. ( 5 times 10^{-4} T ) | 12 |

581 | A magnetic needle is kept in a nonuniform magnetic field. It A. may experience a force but certainly not a torque B. may experience a torque but certainly not a force C. may experience both a torque as well as force D. will certainly experience neither a force not a torque | 12 |

582 | A dip circle shows an apparent dip of ( 60^{0} ) at a place where the true dip is ( 45^{0} ) If the dip circle is rotated by ( 90^{0}, ) what will be the apparent dip? ( ^{mathbf{A}} cdot cos ^{-1} sqrt{frac{2}{3}} ) B. ( tan ^{-1} sqrt{frac{2}{3}} ) ( c cdot sin ^{-1} sqrt{frac{2}{3}} ) D. ( cot ^{-1} sqrt{frac{2}{3}} ) | 12 |

583 | For diamagnetic materials, magnetic susceptibility is A. Small and negative B. Small and positive c. Large and negative D. Large and positive | 12 |

584 | A South pole and North pole of each strength ‘m’ are placed at the two corners of an equilateral triangle of side ‘a’. The resultant magnetic induction field strength at the third vertex is : A. o (zero) в. ( frac{2 mu_{0}}{4 pi} frac{m}{d^{2}} ) c. ( frac{mu_{0}}{4 pi} frac{m}{d^{2}} ) D. ( frac{3 mu_{0}}{4 pi} frac{m}{d^{2}} ) | 12 |

585 | Observe the given figure and identify the correct statements. (i) Poles 1,3 and 5 are unlike poles (ii) Poles 2,4 and 6 are like poles (iii) Pole 1 will attract pole 3 and 5 (iv) Pole 4 will be attracted by pole 1 begin{tabular}{|l|l|l|} hline 1 & 2 & 3 & 4 & 5 \ hline Magnet & Magnet & Magnet end{tabular} A. Only (i) and (iii) B. Only (ii) and (iv) c. Only (i) and (ii) D. Only (iii) and (iv) | 12 |

586 | Assertion (A): To protect any instrument from external magnetic field, it is put inside an iron box Reason (R) : Iron is a ferromagnetic substance A. Both A and R are true and R is the correct explanation of A B. Both A and R are true and R is not correct explanation of c. A is true, but R is false D. A is false, but R is true | 12 |

587 | A student uses a magnetic compass to perform a laboratory experiment in the Northern Hemisphere. She then carries the same magnetic compass with her to the Southern Hemisphere, taking care not to damage the compass in any way. When she reaches her destination at the equivalent latitude and longitude in the Southern Hemisphere, she prepares to perform the same laboratory experiment. The student looks at the compass before performing the experiment to see if the compass needle has changed. How has the compass changed? A. The compass needle points ( 90^{circ} ) to the left of the expected direction B. The compass needle points ( 90^{circ} ) to the right of the expected direction c. The compass needle slowly rotates in a counter clockwise direction D. The compass needle slowly rotates in a clockwis tion as been no he co | 12 |

588 | A dip needle on a plane perpendicular to magnetic meridians will remain A. horizontal B. vertical c. inclined at ( 45^{circ} ) with horizontal D. in any direction | 12 |

589 | A watch glass containing some powdered substance is placed between the pole pieces of a magnet. Deep concavity is observed at the centre. The substance in the watch glass is A. iron B. chromium c. carbon D. woodd | 12 |

590 | To explain ferromagnetism, we use A. orbital electron hypothesis B. spinning electron hypothesis C. domain theory D. Langevin theory | 12 |

591 | An aeroplane with wing span ( 50 m ) is flying horizontally with a speed of ( 360 k m / h r ) over a place where the vertical component of the earth’s magnetic field is ( 2 times 10^{-4} W b / m^{2} . ) The potential difference between the tips of the wings would be A . ( 0.1 V ) в. ( 1.0 V ) ( c .0 .2 V ) D. ( 0.01 V ) | 12 |

592 | A bar magnet is ( 10 mathrm{cm} ) long is kept with its north (N)-pole pointing north. A neutral point is formed at a distance of ( 15 mathrm{cm} ) from each pole:Given the horizontal component of earth’s field is 0.4 Gauss, the pole strength of the magnet is ( A cdot 9 A-m ) B. 6.75 A-m c. 27 A-m D. 1.35 A-m | 12 |

593 | The vertical component of the earth’s magnetic field is: A. zero at the magnetic pole B. Zero at the geographic pole c. Same everywhere D. zero at the magnetic equator | 12 |

594 | A magnetic dipole is placed in a uniform magnetic fields, B, the potential energy is minimum when dipole is A. Parallel to B B. Perpendicular to B c. Inclined at an angle of 450 to ( B ) D. Anti-parallel to B | 12 |

595 | When a bar magnet is broken into two pieces: A. we will have a single pole on each piece B. each piece will have two unlike poles c. each piece will have two like poles D. none of these | 12 |

596 | A conducting rod of length ( 2 mathrm{m} ) is placed on a horizontal table in north-south direction. It carries a current of 5 A from south to north. Find the direction and magnitude of the magnetic force acting on the rod. Given that the Earth’s magnetic field at the place is ( 0.6 times ) ( 10^{-4} T ) and angle of dip is ( frac{pi}{6} ) | 12 |

597 | A material produces a magnetic field which helps the applied magnetic field, then it is This question has multiple correct options A. diamagnetic B. paramagnetic c. electro magnetic D. ferro magnetic | 12 |

598 | Earth’s magnetic field inside a closed iron box, as compared to that outside is A. same B. less c. more D. zero | 12 |

599 | Magnetic lines form continuous closed loops. Why? | 12 |

600 | The magnetic induction due to short bar magnet on its axial line at a distance ‘ ( d ) ‘ is ‘ ( B ) ‘. What is the magnetic induction due to the same bar magnet on the same line at a distance (a) ( d / 4 ? ) (b) ( 4 d / 5 ? ) (b) ( 125 / 64 B ) в. (а) ( 64 B ) (b) ( 125 / 64 B ) c. (a) ( 32 B ) (b) ( 125 / 32 B ) D. (a) ( 64 B ) (b) ( 125 / 32 B ) | 12 |

601 | State the characteristics of magnetic lines of force. | 12 |

602 | Current is flowing through a conductor and creates a magnetic field. Assume that this is the only source of the magnetic field. Reversing a current in a straight conductor with no change to the magnitude(ampere value) will cause a A. Reduction in the magnetic field B. Disappearance of the magnetic field C. Reversal of the direction of the magnetic field D. Reversal and reduction of the magnetic field | 12 |

603 | The pole strength of a bar magnet is 2 Am. If the field at poles are ( 0.2 mathrm{T} ) and 0.22 T, then the force acting on the bar magnet is consider field direction to be same A. ( 0.4 mathrm{N} ) B. 0.04N c. ( 0.44 mathrm{N} ) D. 0.8N | 12 |

604 | A ball of superconducting material is dipped in liquid nitrogen and placed near a bar magnet. In which direction will it move? A. Away from bar magnet c. Around the bar magnet D. Remain constant | 12 |

605 | The strength of magnetic field around a bar magnet: A. decrease with the decrease in distance from the magnet B. decrease with the increase in distance from the magnet c. remain constant with increase in distance from magnet D. becomes zero with decrease in distance from magnet | 12 |

606 | Nickel shows ferromagnetic property at room temperature. If the temperature is increased beyond Curie temperature, then it will show the A. anti ferromagnetism B. no magnetic property c. diamagnetism D. paramagnetism | 12 |

607 | ( mathbf{A} ) is a region around a magnet where magnetic lines of force act. | 12 |

608 | The relative permeability of silicon is 0.99837 and that of palladium is ( 1.00692, ) choose the correct option from the following: A. silicon is paramagnetic and palladium is ferromagnetic B. silicon is ferromagnetic and palladium is paramagnetic c. silicon is diamagnetic and palladium is paramagnetic D. Both are paramagnetic | 12 |

609 | Which of the following is the use of superconductor? A. They are used in powerful electromagnets B. They are used in microwaves c. They are used in MRI D. All of the above | 12 |

610 | A ( 10 mathrm{m} ) long copper wire while remaining in the east-west horizontal direction is falling down with a constant speed of ( 5.0 mathrm{m} / mathrm{s} . ) If the horizontal component of the earth’s magnetic field ( 0.30 times ) ( 10^{-4} W ) erber ( / m^{2} ) What is the instantaneous value of the e.m.f induced in water? A. 0.15 volts B. 1.5 volts c. 0.15 mili volts D. 1.5 mili volts | 12 |

611 | A short bar magnet has a magnetic moment of ( 0.39 J T^{-1} . ) The magnitude and direction of the magnetic field produced by the magnet at a distance of ( 20 mathrm{cm} ) from the centre of the magnet on the equatorial line of the magnet is A. 0.049 G, N-S direction B. 4.9 G, S-N direction c. 0.0195 G, S-N direction D. ( 19.5 mathrm{G} ), N-S direction | 12 |

612 | ( frac{a}{k} ) | 12 |

613 | The ratio of the radii if gyration of a circular disc and a circular ring of same masses and radii about a tangential axis parallel to their plane is A. ( sqrt{6}: sqrt{5} ) B. ( 1: sqrt{2} ) c. ( sqrt{5}: sqrt{6} ) D. None of these | 12 |

614 | A ferromagnetic material heated above its curie temperature. Which one is a correct statement? A. Ferromagnetic domains are perfectly arranged B. Ferromagnetic domains become random c. Ferromagnetic domains are not influenced D. Ferromagnetic material changes into diamagnetic materia | 12 |

615 | A bar magnet is demagnetized by inserting it inside a solenoid of length ( 0.2 m, 100 t u r a s, ) and carrying a current of ( 5.2 A . ) The coercivity of the bar magnet is: A. ( 1200 A / m ) в. ( 2600 A / m ) c. ( 5200 A / j m ) D. ( 285 A / m ) | 12 |

616 | Magnetic field at point ‘P’due to following current distribution is A ( cdot frac{mu_{0} I}{pi r^{2}} sqrt{r^{2}-a^{2}} ) В ( cdot frac{mu_{0} i}{2 pi a} ) C ( cdot frac{mu_{0} I}{2 pi r^{2}} sqrt{r^{2}-a^{2}} ) D. ( frac{mu_{0} l a}{2 pi r^{2}} ) | 12 |

617 | 6. The variation of magnetic susceptibility (W) with temperature for a diamagnetic substance is best represented by (a) o (b) of (d) | 12 |

618 | A bar magnet placed in non-uniform magnetic field experiences. A. Only torque B. Only force c. Both torque and force D. Neither force not torque | 12 |

619 | A current of ( 10 mathrm{A} ) is flowing in a wire of length ( 1.5 mathrm{m} . ) A force of ( 15 mathrm{N} ) acts on it when it is placed in a uniform magnetic field of 2 T. The angle between the magnetic field and the direction of the current is: A ( .30^{circ} ) B . ( 45^{circ} ) ( c cdot 60^{circ} ) D. ( 90^{circ} ) | 12 |

620 | If a magnet is suspended at an angle ( 30^{circ} ) to the magnetic meridian, the dip needle makes an angle of ( 60^{circ} ) with the horizontal The true value of dip is : A ( cdot tan ^{-1}(2 / 3) ) B ( cdot tan ^{-1}(3 / 2) ) c. ( tan ^{-1}(3) ) D. ( tan ^{-1}(2) ) | 12 |

621 | The coercivity of a small magnet where the ferromagnet gets demagnetized is ( 3 times 10^{3} A m^{-1} . ) The current required to be passed in a solenoid of length ( 10 mathrm{cm} ) and number of turns ( 100, ) so that the magnet gets demagnetized when inside the solenoid, is: ( A cdot 3 A ) в. ( 6 A ) ( c .30 m A ) D. ( 60 mathrm{mA} ) | 12 |

622 | Two poles of same strength attract each other with a force of magnitude ( F ) when placed at the corners of an equilateral triangle. If a north pole of the same strength is placed at the third vertex, it experiences a force of magnitude A. ( F sqrt{3} ) в. ( F ) c. ( F sqrt{2} ) D. ( 2 F ) | 12 |

623 | Assertion Magnetic lines forms closed loops in nature. Reason Mono-magnetic pole does not exist in nature. 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 |

624 | Which of the following figures represents the magnetic lines of force due to an isolated south pole? ( A ) B. ( c ) D. | 12 |

625 | The material for making permanent magnets should have A. high retentivity, high coercivity B. high retentivity, low coercivity c. low retentivity, high coercivity D. low retentivity, low coercivity | 12 |

626 | For protecting a sensitive equipment from external magnetic field, it should be A. placed inside an iron can B. placed inside an aluminium can c. surrounded with fine copper sheet D. wrapped with insulation around it when passing current through it | 12 |

627 | Two magnetic poles each of magnetic pole strength ( 16 A m ) are placed at a distance of ( 2 m ) apart. Find magnetic force acting on each pole. A ( cdot 4 times 10^{-7} N ) В. ( 16 times 10^{-7} N ) c. ( 32 times 10^{-7} N ) D. ( 64 times 10^{-7} N ) | 12 |

628 | A line joining places of same declination is called A . agonic B. isoclinic c. isodynamic D. isogonal | 12 |

629 | The magnetism is minimum . in a bar magnet. A. near the ends B. near the middle c. at the ends D. at the middle | 12 |

630 | A dip of needle shows a dip of ( delta ) when placed in magnetic meridian. Now, the vertical plane in which the needle moves is rotated by an angle ( alphaleft(<90^{0}right) ) from the place of the magnetic meridian. With what angle the needle will dip ( A cdotdelta ) ( c .=delta ) D. cant be determined | 12 |

631 | The horizontal component of the flux density of earth’s magnetic field is ( 1.7 times 10^{-5} T . ) The value of the horizontal component of the intensity of earth’s magnetic field will be: A ( cdot 24.5 A m^{-1} ) B. ( 13.5 A m^{-1} ) c. ( 1.53 A m^{-1} ) D. ( 0.35 A m^{-1} ) | 12 |

632 | The distance between a north pole of strength ( 6 times 10^{-3} A m ) and south pole of strength ( 8 times 10^{-3} mathrm{Am} ) is ( 10 mathrm{cm} . ) The poles are separated in air. The force between them: A ( cdot 4.8 times 10^{-11} N ) В. ( 24 times 10^{-11} N ) ( mathbf{c} cdot 48 times 10^{-11} N ) D. ( 24 times 10^{-12} N ) | 12 |

633 | A thin iron ring with mean diameter ( d=50 mathrm{cm} ) supports a winding consisting of ( N=800 ) turns carrying current ( boldsymbol{I}=mathbf{3 . 0} boldsymbol{A} . ) The ring has a cross cut of width ( b=2.0 ) mm. Neglecting the scattering of the magnetic flux at the gap edges, and using the plot shown in figure above, find the permeability of iron under these conditions. | 12 |

634 | A ring is made of a wire having a resistance ( R_{0}=12 Omega ). Find the points ( A ) and ( mathrm{B} ) as shown in fgure at which a current carrying conductor should be connected so that the resistance ( R ) of the sub circuit between these points is equal to ( frac{8}{3} Omega ) A ( cdot frac{l_{1}}{l_{2}}=frac{3}{8} ) B ( cdot frac{l_{1}}{l_{2}}=frac{1}{2} ) ( mathbf{c} cdot frac{l_{1}}{l_{2}}=frac{5}{8} ) D. ( frac{l_{1}}{l_{2}}=frac{1}{3} ) | 12 |

635 | Curie temperature is the temperature above which (a) a paramagnetic material becomes ferromagnetic (b) a ferromagnetic material becomes paramagnetic (c) a paramagnetic material becomes diamagnetic (d) a ferromagnetic material becomes diamagnetic (AIEEE 2003) | 12 |

636 | State True or False. Magnetic lines of force are closed continuous curves. | 12 |

637 | Magnetically aligned atoms in a magnetic material forms a cluster. The cluster is called a: A. Domain B. Molecule c. Pole D. charge E. Electron cloud | 12 |

638 | Discuss the special properties of ferromagnetic materials. | 12 |

639 | Two short magnets of magnetic moment ( 1000 A m^{2} ) are placed as shown at the corners of a square of side 10 ( c m . ) The net magnetic induction at ( P ) is A ( .0 .1 T ) B. ( 0.2 T ) c. ( 0.3 T ) D. ( 0.4 T ) | 12 |

640 | Among the following has the highest retentivity. A. aluminium B. steel c. nickel D. soft iron | 12 |

641 | Th direction of magnetic lines of force of a bar magnet is: A. from south to north pole B. from north to south pole c. across the bar magnet D. from south to north pole inside the magnet and from north to south pole outside the magnet | 12 |

642 | Isogonic lines of a magnetic map represent lines joining places with same A. ( B ) н B. dip c. zero dip D. declination | 12 |

643 | Which of the following does not form magnetic element? ( A cdot B H ) в. ( B v ) ( c . ) dip D. declination | 12 |

644 | Ferromagnetism is not found in A. conductors B. semiconductors c. cobalt D. gases | 12 |

645 | Magnetic lines of force : A. Always intersect. B. Are closed curves. C. Tend to crowd far away from the poles of a magnet. D. Do not pass through vacuum. | 12 |

646 | ( frac{n}{L} ) | 12 |

647 | Three identical bars ( A, B ) and ( C ) are made of different magnetic materials. When kept in a uniform magnetic field, the field lines around them look as follows: Make the correspondence of these bars with their material being diamagnetic ( (D), ) ferromagnetic ( (boldsymbol{F}) ) and paramagnetic ( (boldsymbol{P}) ) A. ( A leftrightarrow F, B leftrightarrow P, C leftrightarrow D ) в. ( A leftrightarrow P, B leftrightarrow F, C leftrightarrow D ) c. ( A leftrightarrow D, B leftrightarrow P, C leftrightarrow F ) D. ( A leftrightarrow F, B leftrightarrow D, C leftrightarrow P ) | 12 |

648 | Magnetic lines do not intersect one- another because: A. they are at a distance B. they are in the same direction C. they are parallel to one another D. in the point of intersection there will be two direction of the magnetic field, which is impossible | 12 |

649 | A unit magnetic pole is that pole which repels an identical pole at a 1 meter distance with a force of В. ( 10^{-7} N ) ( mathbf{c} cdot 10^{-5} N ) D. ( 10^{-4} N ) | 12 |

650 | The temperature at which the domain structure gets destroyed and ferromagnetic substance is converted into paramagnetic substance is called as A. Domain B. Curie Temperature c. Rowland D. Magnetic Field Intensity | 12 |

651 | The hysteresis cycle for the material of a transformer core is: A. short and wide B. tall and narrow. c. tall and wide D. short and narrow | 12 |

652 | Assertion A disc-shaped magnet is deviated above a superconducting material that has been cooled by liquid nitrogen. Reason Superconductors repel a magnet. | 12 |

653 | Curie temperature is the temperature above which A. a paramagnetic material becomes ferromagnetic B. a ferromagnetic material becomes paramagnetic C . a paramagnetic material becomes diamagnetic D. a ferromagnetic material becomes diamagnetic | 12 |

654 | Soft iron is used for the construction of electromagnets because for iron A. the area of hysteresis loops is more B. coersive force is high. C. retentivity is high D. magnetic saturation limits is high and coercivity is low | 12 |

655 | If the angle of dip at a certain place is ( 45^{circ} ) then the horizontal component ( boldsymbol{H} ) vertical component ( V ) and total intensity ( I ) of earth’s magnetic field have the correct relationship given by : A. ( H=sqrt{2} V ) В. ( I=sqrt{2} V ) ( mathbf{c} cdot H=2 V ) D. ( H=sqrt{2} H ) | 12 |

656 | The areas under the I-H hysteresis loop and B-H hysteresis loop are denoted by ( A_{1} ) and ( A_{2}, ) then the ratio of ( frac{A_{2}}{A_{2}} ) is given by ( A cdot mu_{0} ) в. ( frac{1}{mu_{0}} ) ( c cdot 1 ) D. ( sqrt{mu_{0}} ) | 12 |

657 | State whether True or False: Hysteresis is the number of lines of force per unit area in a magnetic field. A. True B. False | 12 |

658 | Assertion Paramagnetic substances get weakly attracted to a magnet. Reason They have tendency to move from a region of strong magnetic field to weak magnetic 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. Both Assertion and Reason are incorrect | 12 |

659 | 66. The dip at a place is d. For measuring it, the axis of the din needle is perpendicular to the magnetic meridian. If the axis of the dip needle makes angle with the magnetic meridian the apparent dip will be given tan 8, which is equal to (a) tan d cos e (b) tan 8 sec (c) tan sin e (d) tan 8 cosec o 1.. . c | 12 |

660 | At a place on Earth, the vertical component of Earth’s magnetic field is ( sqrt{3} ) times its horizontal component. The angle of dip at this place is A ( .30^{circ} ) В. ( 60^{circ} ) ( c cdot 45^{circ} ) D. ( 0^{circ} ) | 12 |

661 | A circular coil of radius ( 10 mathrm{cm}, 500 ) turns and resistance ( 2 Omega ) is placed with its plane perpendicular to the horizontal component of the earth’s magnetic field It is rotated about its vertical diameter through ( 180^{circ} ) in 0.25 s. Estimate the magnitudes of the emf and current induced in the coil. Horizontal component of earth’s magnetic field at the place is ( 3.0 times 10^{-5} mathrm{T} ) | 12 |

662 | The B-H curve for a ferromagnet is shown in the figure. The ferromagnet is placed inside a ling solenoid with 1000 turns/cm.. The current that should be passed in the solenoid to demagnetise the ferromagnet completely is: ( A cdot 2 m A ) В. ( 1 m A ) ( c .3 m A ) D. None of these | 12 |

663 | Draw the pattern of magnetic field lines for a bar magnet. | 12 |

664 | If the vertical component of earth’s magnetic field at a place is ( sqrt{3} ) times the horizontal component, then the value of dip at that place is A .60 B . 45 c. 30 D. ( 15^{circ} ) | 12 |

665 | A short bar Magnet with its north pole facing North forms a neutral point P in the horizontal plane. If the magnet is rotated by ( 90^{0} ) in the horizontal plane, the net magnetic induction at ( mathrm{P} ) is: (Horizontal component of earths magnetic field is ( B_{H} ) ) A. 0 в. ( 2 B_{H} ) c. ( frac{sqrt{5}}{2} B_{H} ) D. ( sqrt{5} B_{H} ) | 12 |

666 | Susceptibility is large and positive for A. para magnetio B. diamagnetic C. ferro magnetic D. electromagnetic | 12 |

667 | At a certain temperature, a ferromagnetic material becomes paramagnetic. What is this temperature called? | 12 |

668 | Assertion: At high temperature, a ferromagnet becomes a paramagnet. Reason: The ferromagnetic property depends on temperature A. If both assertion and reason are true and reason is the correct explanation of assertion. B. If both assertion and reason are true and reason is not the correct explanation of assertion. c. If assertion is true but reason is false. D. If both assertion and reason are false | 12 |

669 | A copper rod ( 10 mathrm{cm} ) long rotates 1800 times per minute about an axis passing through one end at a right angle to the rod. A uniform magnetic field of 1 tesla is applied perpendicular to the plane of rotation. The voltage induced between the ends of the rod is A . ( 0.235 mathrm{v} ) B. ( 0.942 mathrm{V} ) c. ( 2.35 v ) D. zero | 12 |

670 | Write Sl unit of magnetic dipole moment. | 12 |

671 | When a proton is released vest in a room. it starts with an initial acceleration ( a_{0} ) towards west. When it is projected towards north with a speed ( v_{0} ) it moves with an initial acceleration ( 3 a_{0} ) toward west. The electric and magnetic fields in the room are ( mathbf{A} cdot frac{m a_{0}}{e} ) east ( , frac{3 m a_{0}}{e v_{0}} u p ) B. ( frac{m a_{0}}{e} ) east, ( frac{3 m a_{0}}{e_{e 0}} ) down ( mathbf{C} cdot frac{m a_{0}}{e} ) west ( , frac{2 m a_{0}}{e v_{0}} u p ) D. ( frac{m a_{0}}{e} ) west ( , frac{2 m a_{0}}{e_{e v}} d o w n ) | 12 |

672 | A magnetic field is produced by the two magnets as shown, the magnetic field is A. uniform B. non-uniform and ( N ) is a strong end C. non-uniform and ( S ) is a strong end D. uniform and both ( N ) and ( S ) ends are equally strong | 12 |

673 | Assertion: The product of magnetic susceptibility and absolute temperature for a paramagnetic substance is constant. Reason: Susceptibility is positive but very small for paramagnetic substance A. If both assertion and reason are true and reason is the correct explanation of assertion. B. If both assertion and reason are true and reason is not the correct explanation of assertion. c. If assertion is true but reason is false D. If both assertion and reason are false | 12 |

674 | Assertion Substances which at room temperature retain their ferromagnetic property for a long period of time are called permanent magnets. Reason Permanent magnet can be made by placing a ferromagnetic rod in a solenoid and passing current through it. 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 |

675 | The core of electromagnet is made of soft iron, because a) susceptibility of soft iron is very high b) coercivity of soft iron is very low A. only a is correct B. only b is correct c. both a and b are correct D. both a and b are wrong | 12 |

676 | A magnet has a pole strength of 1000 milli amp.m. The magnetic field intensity at a distance of ( 10 mathrm{cm} ) from its North pole is ( mathbf{A} cdot frac{25}{pi} A / m ) B . ( frac{pi}{25} A / m ) ( mathbf{c} cdot frac{100}{pi} A / m ) D ( cdot frac{pi}{100} A / m ) | 12 |

677 | Which of the following best describe the spacing of the field lines? A. Indicates the strength of the magnetic field B. Is greatest near the poles c. Is smallest far away from the poles D. Indicates the direction of the magnetic field E. Is the same everywhere around the magnet | 12 |

678 | Susceptibility of ferromagnetic substance is ( A cdot>1 ) в. ( <1 ) c. zero D. | 12 |

679 | The mid points of two small magnetic dipoles of length ( d ) in end-on positions, are separated by a distance ( boldsymbol{x},(boldsymbol{x}>>boldsymbol{d}) ) The force between them is proportional to ( x^{-n} ) where ( n ) is : ( A ) в. ( c ) ( D ) | 12 |

680 | State whether the following statement is True or False. The magnetic lines of force around a bar magnet mutually attract each other. | 12 |

681 | Determine the horizontal component of the earth’s magnetic field at the location. | 12 |

682 | Two short magnets placed along the same axis with their like poles facing each other will repel each other with a force which varies inversely as A. Distance B. Square of distance c. cube of distance D. Fourth power of distance | 12 |

683 | Which of the following is/are correct about magnetic lines of force? A. Are mere directions B. Have no physical reality c. can be used to indicate the direction of the magnetic field at a point D. All of these | 12 |

684 | A frog can be levitated in magnetic field produced by a current in a vertical solenoid placed below the frog. This is possible because the body of the frog behaves as A. Paramagnetic c. Ferromagnetic | 12 |

685 | From the following,pick a property that is associated to ferromagnetic materials only: A. attracting magnetic substance B. hysterisis c. directional property D. susceptibility independent of temperature | 12 |

686 | A diamagnetic material in a magnetic field moves A. perpendicular to field B. from stronger to weaker parts of the field c. from weaker to stronger parts of field D. None of these | 12 |

687 | A piece of material moves very slowly towards a pole of magnet. The material must be A. Diamagnetic B. Ferromagnetic c. Paramagnetic D. Ferrimagnetic | 12 |

688 | Susceptibility is small and positive for A. para magnetic only B. diamagnetic only c. ferro magnetic only D. Both 1 & 3 | 12 |

689 | A ball of superconducting material is dipped in liquid nitrogen and placed near a bar magnet. In which direction will it move then? A. Away from bar magnet c. Around the bar magnet D. Remains constant | 12 |

690 | 56. The magnetic field intensity H at the centre of a long solenoid having n turns per unit length and carrying a current I, when no material is kept in it is (a) Moni (b) nl (d) to | 12 |

691 | A substance is placed in a non uniform magnetic field. It experiences weak force towards the strong field. The substance is ( _{-}-_{-}-_{-}-_{-}-_{-} ) type. A. Ferromagnetic c. Paramagnetic D. None of these | 12 |

692 | Define the terms: ¡) Declination ii) Inclination or Dip. | 12 |

693 | Curie temperature is the temperature above which A. a ferromagnetic material becomes paramagnetic B. a paramagnetic material becomes diamagnetic C . a ferromagnetic material becomes diamagnetic D. a paramagnetic material becomes ferromagnetic. | 12 |

694 | A dip needle shows angle of dip ( tan ^{-1}left(frac{2}{sqrt{3}}right) ) in a vertical plane which is at an angle of ( 60^{0} ) with the magnetic meridian. The real dip at the place is then A ( cdot 0^{circ} ) B . ( 45^{circ} ) ( c cdot 30^{0} ) D. ( 90^{circ} ) | 12 |

695 | paramagnetic substance will look like ( A ) B. ( c ) D. | 12 |

696 | The real angle of dip, if a magnet is suspended at an angle of ( 30^{0} ) to the magnetic meridian and the dip needle makes an angle of ( 45^{0} ) with horizontal is : ( ^{A} cdot tan ^{-1}left(frac{sqrt{3}}{2}right) ) B ( cdot tan ^{-1}(sqrt{3}) ) ( ^{mathbf{c}} cdot tan ^{-1}left(frac{1}{2}right) ) D ( cdot tan ^{-1}left(frac{2}{sqrt{3}}right) ) | 12 |

697 | The horizontal and vertical components of the Earth’s magnetic field at a place are each equal to 0.35 gauss. Find the angle of dip at the places. | 12 |

698 | The earth’s magnetic field at the equator is approximately ( 0.4 G . ) The earth’s dipole moment is : ( left(boldsymbol{R}_{e}=mathbf{6 . 4} times mathbf{1 0}^{mathbf{6}} boldsymbol{boldsymbol { m }}right) ) A ( cdot 4 times 10^{2} A m^{2} ) B . ( 1.05 times 10^{23} mathrm{Am}^{2} ) c. ( 4 times 10^{-5} mathrm{Am}^{2} ) D. ( 1.05 times 10^{-20} mathrm{Am}^{2} ) | 12 |

699 | a bar magnet is made to fall through a long vertical copper tube .The speed (v) of the magnet as a function of time (t) is best represented by ( A ) B. ( c ) ( D ) | 12 |

700 | A beam has intensity ( 2.5 times 10^{14} W m^{-2} ) The ratio of electric and magnetic fields in the beam is A . ( 3.44 T ) в. ( 3.14 T ) c. ( 1.004 T ) D. 1.447 | 12 |

701 | A watch glass containing some powdered substance is placed between the pole pieces of a magnet. Deep concavity is observed at the center. The substance in the watch glass is (assume poles are far) A. iron B. chromium c. carbon D. woodd | 12 |

702 | A sensitive magnetic instrument can be shielded very effectively from outside magnetic fields by placing it inside a box of: A. wood B. plastic C. metal of high conductivity D. soft iron of high permeability | 12 |

703 | A charge is projected with a velocity of ( 10^{5} m / s . ) In a perpendicular magnetic field. Find the magnetic of a transverse electric field if if moves undeflected ( left(B=4 * 10^{-5} Tright) ) A . ( 4 mathrm{N} / mathrm{C} ) в. ( 4 times 10^{-2} mathrm{N} / mathrm{C} ) c. ( 24 times 10^{-2} N / C ) D. not possible | 12 |

704 | What are permanent magnets? Give one example. | 12 |

705 | A small, magnetized sphere A of pole strength ( m ) is counter-poised by a pan in a balance. Another magnetised sphere B of the same mass as ( A ) is placed below ( A ) so that their centres are at a distance ( 1 mathrm{cm} . ) If ( mathrm{A} ) and ( mathrm{B} ) are unlike poles of same strength and to restore counter the weight in the pan is increased by ( 500 g m ) the pole strength of each sphere is: A ( .1 .4 A m ) B. ( 9.8 A m ) c. ( 0.7 A m ) D. ( 70 A m ) | 12 |

706 | 43. Which of the following is most suitable for the core of electromagnets? (a) Soft iron (b) Steel (c) Copper-nickel alloy (d) Air | 12 |

707 | What are the changes observed at the transition temperature in superconductors? | 12 |

708 | A bar magnet is ( 0.10 mathrm{m} ) long and its pole strength is ( 120 A ) m. Find magnitude of magnetic field at a point on the its axis at a distance ( 20 mathrm{cm} ) from ¡t. | 12 |

709 | Magnetic lines of force always cross each other. Is the given statement true or false? Justify. | 12 |

710 | The magnetic susceptibility of a paramagnetic material at ( -73^{0} ) is ( 0.0075, ) its value at ( -173^{0} mathrm{C} ) will be A . 0.0045 B. 0.0030 c. 0.015 D. 0.0075 | 12 |

711 | Permanent magnets should have A. High retentivity and low coercivity. B. Low retentivity and high coercivity. C. High retentivity and high coercivity. D. Low retentivity and low coercivity. | 12 |

712 | Which one of the following statements best describes the nature of the field lines due to a bar magnet? A. Field lines start from the north pole and end on the south pole. Any number of field lines can pass through a point B. Field lines start from the north pole and end on the south pole. Only one field line passes through a point C. Field lines are continuous lines passing inside and outside the magnet. Only one field line passes through a point D. Field lines are continuous lines passing inside and outside the magnet. Any number of field lines can pass through a point | 12 |

713 | The resultant magnetic field at the center of a bar magnet is zero. A. True B. False | 12 |

714 | Magnetic dipole moment is a: A. Scalar quantity B. Vector quantity C. Constant quantity D. None of these | 12 |

715 | Domain formation is the necessary feature of A. ferromagnetism B. diamagnetism c. paramagnetism D. all of these | 12 |

716 | Curie temperature is the temperature above which A. Paramagnetic material becomes ferromagnetic material B. Ferromagnetic material becomes diamgnetic material C. Ferromagnetic material becomes paramagnetic material D. Paramagnetic material becomes diamagnetic material | 12 |

717 | The magnetic field at point ( C ) as shown in the figure is: ( A ) [ frac{mu_{0} M_{0}}{2 pi r_{0}^{3}} ] B. ( frac{sqrt{2} mu_{0} M_{0}}{2 pi r_{0}^{3}} ) C. zero D. ( frac{sqrt{2} mu_{0} M_{0}}{4 pi r_{0}^{3}} ) | 12 |

718 | 42. When a ferromagnetic material is heated to temperature above its Curie temperature, the material (a) is permanently magnetized (b) remains ferromagnetic (c) behaves like a diamagnetic material (d) behaves like a paramagnetic material | 12 |

719 | The magnetic induction at a distance d from the magnetic pole of the unknown strength ( m ) is ( B ). If an identical pole is now placed at a distance of ( 2 mathrm{d} ) from the first pole, the force between the two poles is A. ms B. ( frac{m B}{2} ) ( mathbf{c} cdot frac{m B}{4} ) D. 2mB | 12 |

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