# Current Electricity Questions

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

#### List of current electricity Questions

Question NoQuestionsClass
1Potentiometer measures the potential difference more accurately than a voltmeter because:
A. it has a wire of high resistance
B. it has a wire of low resistance
c. it does not draw current from external circuit
D. it draws a heavy current from external circuit
12
2A motor of ( 50 ~ W ) runs for 20 hrs. How
many ‘units’ ( ( k W h ) ) of electrical energy are consumed?
( mathbf{A} .5 mathrm{kWh} )
в. ( 2 k W h )
( c cdot 1 k W h )
D. ( 2.5 mathrm{kWh} )
12
3The relaxation time
(t) is the:
A. Time taken by an electron to drift from one end of a conductor to the other.
B. Time taken by an electron to travel unit distance through the conductor.
c. The time between two successive collisions of a free
electron with the atoms of the metal.
D. Time for which a free electron is subjected to the electric field
12
4Between any two points in a circuit, the sum of all ( ldots ldots . . . . . . . ) is the same through
any pathway.
A . charge
B. current
c. potential difference
D. resistance
12
5(i) State Ohm’s law.
(ii) A metal wire of resistance ( 6 Omega ) is
stretched so that its length is increased to twice its original length. Calculate its new resistance.
12
6Explain the term ‘drift velocity’ of
electrons in a conductor. Hence obtain
the expression for the current through a conductor in terms of ‘drift velocity’
12
7The resistance of germanium with rise in temperature.
A. increases
B. decreases
c. remains the same
D. first increases then decreases
12
8An electric bulb is rated ( 220 V ) and
( 100 W, ) when it is operated on ( 110 V )
the power consumed will be
A . ( 100 mathrm{W} )
в. ( 75 mathrm{W} )
( mathbf{c} .50 W )
D. ( 25 W )
12
9Given ( boldsymbol{R}_{1}=mathbf{5 . 0} pm mathbf{0 . 2} mathbf{Omega} ) and ( boldsymbol{R}_{2}= )
( 10.0 pm 0.1 Omega . ) What is the total
resistance in parallel with possible ( % )
error?
12
10A bulb uses 5000 J of energy in 10 s calculate its power.
A. ( 50 J / ) s
B. 500w
( c .5 w )
D. 600 J/s
12
11Four wires are made from the same
metal.
Which wire has the lowest resistance?
A. Length of wire / ( mathrm{cm}-20 ), Diameter of wire / ( mathrm{mm}-0.20 )
B. Length of wire / ( mathrm{cm}-20 ), Diameter of wire / ( mathrm{mm}-0.40 )
C. Length of wire / ( mathrm{cm}-40 ), Diameter of wire / ( mathrm{mm}-0.20 )
D. Length of wire / ( mathrm{cm}-40 ), Diameter of wire / ( mathrm{mm}-0.40 )
12
12A cell of emf ‘E’ and internal resistance
is connected across a variable resistor
R’. Plot a graph showing variation of terminal voltage ‘V’ of the cell versus the current ‘I’. Using the plot, show how the emf of the cell and its internal
resistance can be determined.
12
13A potentiometer wire of length ( 10 m ) is connected in series with a battery. The
e.m.f. of a cell balances against ( 250 mathrm{cm} ) length of wire. If length of potentiometer wire is increased by ( 1 m, ) the new
balancing length of wire will be
( mathbf{A} cdot 2.00 m )
B. ( 2.25 m )
c. ( 2.50 m )
D. ( 2.75 m )
12
14A group of N cells whose emf varies
directly with the internal resistance as
per the equation ( boldsymbol{E}_{N}=mathbf{1 . 5 r}_{N} ) are
connected as shown in the figure. The current I in the circuit is :-
A . 5.1 A
B. 0.51 A
( c cdot 1.5 mathrm{A} )
D. 0.15 A
12
15A block of carbon, ( 1.0 mathrm{cm} ) by ( 2.0 mathrm{cm} ) by
( 5.0 mathrm{cm}, ) has a resistance of 0.015
between its two smaller faces. What is
the resistivity of carbon?
A ( cdot 1 times 10^{-8} Omega m )
В. ( 2 times 10^{-8} Omega m )
c. ( 4 times 10^{-5} Omega m )
D. ( 6 times 10^{-8} Omega m )
12
16A time varying current ( i ) in passed
through a resistance ( R ) as shown in
figure. The total heat generated in the
resistance is:
A ( cdot 11 i_{0}^{2} R t_{0} )
B. ( 13 i_{0}^{2} R t_{0} )
( mathbf{c} cdot 17 i_{0}^{2} R t_{0} )
D. ( 15 i_{0}^{2} R t_{0} )
12
17A cell of emf ( 2 mathrm{V} ) delivers current equal to
( 20 % ) of the maximum current, which it
can produce through a resistance ( 4 Omega ) Its internal resistance is
A . ( 0.1 Omega )
B. 19
( c cdot 0.5 Omega )
D. 1.5.
12
18How much resistance should be
connected to ( 15 Omega ) resistor shown in the
circuit in adjoining figure below so that the points ( mathrm{M} ) and ( mathrm{N} ) are at the same
potential
12
19A battery of e.m.f. ( 3.0 mathrm{V} ) supplies current through a circuit in which the
resistance can be changed. A high resistance voltmeter is connected
across the battery. When the current is
( 1.5 mathrm{A}, ) the voltmeter reads ( 2.7 mathrm{V} ). The
internal resistance of the battery is
A . ( 4 Omega )
в. ( 1.2 Omega )
c. ( 0.2 Omega )
D. 2Omega
12
20Copper metal is a:
A. good conductor of electricity
C . magnetic substance
E. none of these
12
21A battery of e.m.f. ( 15 mathrm{V} ) and internal resistance ( 2 Omega ) is connected to two
resistors of resistance 4 ohm and 6 ohm
joined in series. What is the electrical energy spent per minute in 6 ohm
resistor?
A . 562.5
B. 180 J
c. 456.5 J
D. 360 J
12
221 ampere is same as
( mathbf{A} cdot 1 C s^{-1} )
B. ( 1 C s )
( mathbf{c} cdot 1 J C^{-1} )
D. ( 1 V C^{-1} )
12
A. ( 2 v )
B. 2.04
c. ( 1.96 mathrm{v} )
D. 1.0
12
24connected in a circuit as shown in
figure. The galvanometer is kept
undeflected always. Here ( A B=l . ) When
the switch ( S ) is connected to point ( S_{1} )
( B P=x_{1} ) and when the switch ( S ) is
connected to point ( S_{2}, B P=x_{2} . ) Here
the ratio of emf’s of the two batteries,
i.e., ( varepsilon_{1} / varepsilon_{2} ) equal/s:
( mathbf{A} cdot x_{1} / x_{2} )
B. ( x_{2} / x_{1} )
c. ( frac{left(l-x_{1}right)}{left(l-x_{2}right)} )
D. ( frac{left(l-x_{2}right)}{left(l-x_{1}right)} )
12
25Three resistances of ( 8 Omega, 16 Omega ) and ( 4 Omega )
are joined in parallel. If each resistor is
rated ( 0.5 W, ) what is the maximum
voltage that may be applied to the combination?
A . ( 1 V )
в. ( 1.5 V )
( c cdot 2 V )
D. 2.5V
12
26Name two factors on which the internal
resistance of a cell depends.
This question has multiple correct options
A. separation between plates
B. emf of cell
c. area of plates
D. external resistance.
12
27A wire of resistance ( 4 Omega ) is stretched to
twice its original length. In the process of stretching, its area of cross section gets halved. Now, the resistance of the
wire is:
( A cdot 8 Omega )
в. 16 Omega
c. ( 1 Omega )
D. ( 4 Omega )
12
28Material used in heating coils is:
A. Nichrome
B. Copper
c. Silver
D. Gold
12
29Assertion
In a simple electric circuit, positive terminal of the battery is a point of lowest potential
Reason
The electronic current flow in a circuit
is from a point of highest potential to a point of lowest potential
A. Both Assertion and Reason are correct and Reason is the correct explanation for Assertion
B. Both Assertion and Reason are correct but Reason is not the correct explanation for Assertion
c. Assertion is correct but Reason is incorrect
D. Assertion is incorrect but Reason is correct
12
30The equivalent resistance between the points 1 and 7 the adjoining circuit (fig)
will be
( A cdot frac{7}{1} )
12
в. ( frac{5}{6} r )
( c )
D. none of these
12
31A circuit shown in Fig. has resistances
( R_{1}=20 Omega ) and ( R_{2}=30 Omega . ) At what
value of the resistance ( R_{x} ) will the
thermal power generated in it be practically independent of small variations of that resistance. The
voltage between the points ( A ) and ( B )
is supposed to be constant in this case.
12
32The indicates
the multiplier telling you the power of ten to which the two significant digits in color coding of the resistor must be
multiplied (or how many zeros to add)
A. 2nd band
B. 3rd band
c. 4 th band
D. last band
12
33Kirchhoff’s law of meshes is in
accordance with law of conservation of:
A. charge
B. current
c. energy
D. angular momentum
12
34Assertion
Heater wire must have high resistance than connecting wires and high metallic point.
Reason
If resistance is high, the electrical
conductivity will be less.
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
35Electromotive force represents
A . force
B. energy
C. energy per unit charge
D. current
12
36Copper contains ( 8.4 times 10^{28} ) free
electrons ( / m^{3} . ) A copper wire of crosssectional area ( 7.4 times 10^{-7} m^{2} ) carries a
current of 1 A. The electron drift speed is approximately.
A ( cdot 10^{-8} mathrm{m} / mathrm{s} )
B. ( 10^{3} mathrm{m} / mathrm{s} )
( c cdot 1 m / s )
D. ( 10^{-3} mathrm{m} / mathrm{s} )
12
37The balancing length for a cell is ( 560 mathrm{cm} )
in a potentiometer experiment. When an external resistance of ( 10 Omega ) is connected
in parallel to the cell, the balancing length changes by ( 41 c m ). The internal resistance of the cell in ohms is
A . 1.6
B. 1.
( c cdot 12 )
D. 0.8
12
38A carbon film resistor has colour code
Green Black Violet Gold. The value of the
resistor is:
A ( .50 M Omega )
в. 500 М ( Omega )
( mathrm{c} .500 pm 5 % ) М( Omega )
D. ( 500 pm 10 % ) M ( Omega )
12
39Electrical power ( P ) is given by the expression ( P=frac{Q times V}{t} . ) time. What does
( Q ) and ( V ) stand for?
A. Charge, energy
B. Current, voltage
c. current, power
D. Charge, voltage
12
40Current ( I_{1} ) in the following circuit is
( A, O, 4 A )
B . -0.4A
( c . ) о.вА
D . -0.8A
12
41Voltmeters ( V_{1} ) and ( V_{2} ) are connected in
series across a ( D . C . ) line. ( V_{1} ) reads ( 80 V )
and has a per volt resistance of ( 200 Omega )
( V_{2} ) has a total resistance of ( 32 k Omega ). The
line voltage is
( mathbf{A} cdot 120 V )
в. ( 160 V )
( mathbf{c} cdot 220 V )
D. ( 240 V )
12
42Two lamps one rated ( 60 mathrm{W}, 220 mathrm{V} ) and the other ( 40 mathrm{W}, 220 mathrm{V} ) are connected in
parallel to a ( 220 mathrm{V} ) electric supply mains. What is the total current drawn from the
electric mains if the voltage of electric supply is ( 220 mathrm{V} ? )
12
43For a cell, a graph is plotted between the potential difference ( V ) across the
terminals of the cell and the current ( I )
drawn from the cell (see Figure). The
emf and the internal resistance of the
cell are ( E ) and ( r, ) respectively. Then :
A ( . E=2 V, r=0.5 Omega )
B. ( E=2 V, r=0.4 Omega )
c. ( E>2 V, r=0.5 Omega )
D. ( E>2 V, r=0.4 Omega )
12
44When no current is passed through a
conductor
This question has multiple correct options
A. the free electrons do not move
B. the average speed of a free electron over a large period of time is zero
C. the average velocity of a free electron over a large period of time is zero
D. the average of the velocities of all the free electrons at an instant is zero
12
45A charge ( q ) is placed at the centre of the
line joining two equal charges ( Q ). The
system of the three charges will be in equilibrium if ( q ) is equal to?
12
46When connected to the ( 220 mathrm{V} ) mains
supply, the current in a toaster, a kettle, a lamp and a fan is ( 5.2 mathrm{A}, 9.4 mathrm{A}, 0.5 mathrm{A} ) and 2.6A respectively. Which appliance has the greatest electrical resistance?
A. toaster
B. kettlein
c. lamp
D. fan
12
47A battery is delivering same power to
resistance ( R_{1} ) and ( R_{2} . ) Then find the internal resistance of battery :
A. ( frac{R_{1}-R_{2}}{2} )
В. ( R_{1}+R_{2} )
c. ( sqrt{R_{1}+R_{2}} )
D. ( sqrt{R_{1}+R_{2} / 2} )
12
48Find out the resistance:12
49An aluminium wire carrying a current has diameter ( 0.84 mathrm{mm} ). The electric
field in the wire is ( 0.49 V / m . ) What is,
(a) the current carried by the wire?
(b) the potential difference between two points in the wire 12.0 m apart?
(c) the resistance of a ( 12.0 mathrm{m} ) length of this wire?
Specific resistance of aluminum is ( 2.75 times 10^{8} Omega-m )
12
50A metallic wire of resistance ( 20 Omega ) is
stretched such that its length becomes three times. The new resistance of the
wire will be
A ( .6 .67 Omega )
B. ( 60.0 Omega )
c. ( 120 Omega )
D. ( 180 Omega )
12
51( mathbf{1} boldsymbol{A}= )
( mathbf{A} cdot 10^{2} )
B. ( 10^{3} )
( mathbf{c} cdot 10^{-3} )
D. ( 10^{-6} )
12
52The pd a cross terminals of a cell is
found to be 29 volt and 28 volt
respectively when it delivers a current of 1 ampere and 2 ampere respectively. The emf and internal resistance of a cell
are respectively
A. ( 30 mathrm{V}, 2 Omega )
B. 30V,1Omega
c. ( 29 v, 1 Omega )
D. ( 28 mathrm{V}, 2 Omega )
12
53In a potentiometer experiment for measuring the emf of a cell, the null point is at ( 240 mathrm{cm} ) when we have a ( 500 Omega \$ ) resistor in series with the cell and galvanometer. If the series resistance reduced to half, then the null
point will be at:
A. ( 480 mathrm{cm} )
в. 240 ст
( mathrm{c} .120 mathrm{cm} )
D. ( 60 mathrm{cm} )
12
54State Kirchoff’s rules. Use these rules to
find the values of current ( boldsymbol{I}_{1}, boldsymbol{I}_{2}, boldsymbol{I}_{3} ) in
the circuit diagram given
begin{tabular}{|l|l|}
hline( I_{1} ) & ( 1 / 2 V ) & ( gamma_{1}=4 Omega ) \
& \
( vdots ) & 11 \
hline( I_{2} ) & \
( I_{3} ) & ( 4 V ) & ( gamma_{3}=3 Omega ) \
hline
end{tabular}
12
55The drift velocity of electrons in a
conducting wire is of the order of
( 1 m m / s, ) yet the bulb glows very quickly after the switch is put on because
A. the random speed of electrons is very high of the order of ( 10^{-6} mathrm{m} / mathrm{s} )
B. the electrons transfer their energy very quickly through collision.
c. electric field is set up in the wire very quickly, producing a current through each cross section almost intantaneously
D. All the above
12
56The current i in the circuit (see figure)
is :
( A cdot frac{1}{A 5} )
( B cdot frac{1}{15} A )
( c cdot frac{1}{10} A )
( D cdot underline{1} )
12
57Three similar cells, each of emf ( 2 V ) and
internal resistance ( r ) send the same
current through an external resistance of ( 2 Omega, ) when connected in series or in
parallel. Then the magnitude of current flowing through the external resistance is :
( mathbf{A} cdot 0.75 A )
в. ( 1 A )
( c .1 .5 A )
D. zero
12
58The filament of a bulb takes a current
( 0.1 mathrm{A} ) when potential difference across it is ( 0.2 mathrm{V} ). When the potential difference across it becomes ( 1.0 mathrm{V} ), the current
becomes 0.4 A. The resistance of
filament in each case will be
A. ( 2.0 Omega, 2.5 Omega )
B. ( 2.5 Omega, 2 Omega )
c. ( 1.0 Omega, 2.5 Omega )
D. ( 2.0 Omega, 2 Omega )
12
59Copper and silicon is cooled from ( 300 mathrm{K} ) to ( 60 mathrm{K} ), the specific resistance :
A. decreases in copper but increase in silicon
B. increases in copper but decrease in silicon
c. increase in both
D. decrease in both
12
60The graph shown in the figure represents a plot of current versus voltage for given semi-conductor Identify the region. if any, over which the semi-conductor has a negative
resistance
12
61Four similar charges each of magnitude
( Q ) are placed at the four comers of a
square of side ‘a’. The intensity of the
electric field at the intersection of the
diagonal is
A. 0
в. ( frac{Q}{4 pi varepsilon_{0} a^{2}} )
c. ( frac{4 Q}{4 pi varepsilon_{0} a^{2}} )
D. ( frac{Q}{8 pi varepsilon_{0} a^{2}} )
12
62A physicist works in a laboratory where
the magnetic field is 2 T. She wears a
silver necklace enclosing an area 100
( c m^{2} ) of field and having a resistance of
( 0.1 Omega . ) Because of power failure, the
field decays to ( 1 T ) in millisecond. The
electric charge circulated in the
necklace assuming that the magnetic field is perpendicular to area covered by the necklace is
( mathbf{A} cdot 0.01 C )
в. ( 0.001 C )
c. ( 0.1 C )
D. ( 1.0 C )
12
63The effective capacitance between the
point ( mathrm{P} )
and ( Q ) in the given figure is
( mathbf{A} cdot 4 mu F )
B. ( 16 mu F )
c. ( 26 mu F )
D. ( 10 mu F )
12
64A wire has resistance of ( 8 Omega ). If its length is made half by folding, find its resistance after the free ends are
connected to each other
12
65Find the resistance of the voltmeter
A. ( 400 Omega )
B. 200 ( Omega )
c. ( 300 Omega )
D. 500 ( Omega )
12
66In the primary circuit of potentiometer
the rheostat can be varied from 0 to
10Omega. Initially it is at minimum
resistance (zero). Find the length ( boldsymbol{A P} )
(in ( mathrm{m} ) ) of the wire such that the
galvanometer shows zero deflection.
12
67The resistance of a bulb filament is
( 100 Omega ) at a temperature of ( 100^{circ} mathrm{C} ). If its temperature coefficient of resistance
be 0.005 per ( ^{o} C, ) its resistance will
become ( 200 Omega ) at a temperature of :
( mathbf{A} cdot 200^{circ} C )
B. ( 300^{circ} mathrm{C} )
c. ( 400^{circ} mathrm{C} )
D. ( 500^{circ} mathrm{C} )
12
68Explain Krichhoff’s laws with examples.12
69The power consumed in ( 10 Omega ) resistor in
the given circuit is :
A. ( 10 W )
В. ( 8 W )
( c .>10 W )
( D )
12
70Given circuit has ( n ) cells attached to it.
All the cells are identical. When one cell
is reversed, the current decreases to
( 0.7 A . ) The value of ( n ) is
A . 12
B. 16
( c cdot 20 )
( D )
12
71Two cells when connected in series are
balanced on ( 8 m ) on a potentiometer. If
the cells are connected with polarities of one of the cell is reversed, then they
balance on 2 m. The ratio of emf’s of two
cells is
A .3: 4
B. 4: 3
( c .3: 5 )
D. 5: 3
12
72The resistors of resistances ( 2 Omega, 4 Omega, 5 Omega ) are connected in parallel. The total resistance of the combination will be :
A ( cdot frac{29}{10} Omega )
в. ( frac{19}{20} Omega )
c. ( frac{10}{20} Omega )
D. ( frac{20}{19} Omega )
12
73Identify the changes in a circuit on adding a light bulb in parallel to the actual resistance of the circuit. It will:
A. decrease the total resistance
B. increase the total resistance
c. make the voltage lost in each light bulb different
D. make the current through each light bulb the same
E. not change the total current through the circuit
12
74For which of the following dependence of
drift velocity ( v_{d} ) on electric field E is Ohm’s law obeyed?
A ( cdot v_{d} propto E )
B . ( v_{d}= ) constant
( mathbf{c} cdot v_{d} propto sqrt{E} )
D ( cdot v_{d} propto E^{2} )
12
75Draw the experimental set-up to verify
that ( frac{V}{I} ) is constant for a Conductor
12
76For making standard resistance, wire of following material is used
A. Nichrome
B. Copper
c. silver
D. Manganin
12
77Consider a thin square sheet of side ( boldsymbol{L} )
and thickness ( t, ) made of a material of
resistivity ( rho . ) The resistance between
two opposite faces, shown by the shaded areas in the figure is
A. directly proportional to L
B. directly proportional to t
c. independent of
D. independent of t
12
78Deduce the expression for the the equivalent resistance of three resistors
connected in Parallel.
12
79Which of the following has a negative temperature coefficient?
A .
B. Fe
( c . ) мп
D. Agg
12
80No current flows between two charged
bodies when connected if they have
same:
A. capacity
B. charge
c. potential
D. none of the above
12
81An immersion heater is rated ( 836 W . ) It
should heat ( 1 l ) of water from ( 20^{0} C ) to ( 40^{0} )
A. ( 200 s )
B. ( 100 s )
( mathbf{c} .836 s )
D. ( 418 s )
12
82In the circuit shown in figure cells of
emf 2,1,3 and ( 1 V ) respectively having
resistances ( 2 Omega, 1 Omega, 3 Omega ) and ( 1 Omega ) are
their internal resistances respectively.
The potential difference between D and B (in volts)
A ( cdot frac{5}{13} )
в. ( frac{2}{13} )
c. ( frac{10}{13} )
12
83Two wires of Aluminium have same
weight and have lengths of ( 10 mathrm{m} ) and 20m. Their resistances are in the ratio.
A .1: 2
B . 2: 1
c. 4: 1
D. 1: 4
12
84The ratio of resistances between ( A ) and
B before and after the switch ( S ) is
closed:
( mathbf{A} cdot 9: 8 )
B .7: 8
( c cdot 2: 3 )
D. 1: 2
12
85A battery of e.m.f. ( boldsymbol{E} ) has an internal resistance ‘r’. A variable resistance ( boldsymbol{R} ) is
connected to the terminals of the
battery. A current ( I ) is drawn from the
battery. ( V ) is the terminal P.D. If ( R ) alone
is gradually reduced to zero, which of
the following best describes ( I ) and ( V ? )
A. I approaches ( E / r, V ) approaches ( E )
B. I approaches infinity, ( V ) approaches ( E )
c. ( I ) approaches zero, Vapproaches ( E )
D. I approaches ( E / r, V ) approaches zero
12
86Two cells of same emf E but different
internal resistances ( r_{1} ) and ( r_{2} ) are
connected in series with an external
resistance ( R ). The potential drop across
the first cell is found to be zero.
The external resistance ( boldsymbol{R} ) is
A ( cdot r_{1}+r_{2} )
В. ( r_{1}-r_{2} )
c. ( r_{2}-r_{1} )
D. ( r_{1} r_{2} )
12
87The point in a Meter bridge is at ( 35.6 mathrm{cm} . ) If the resistances in the gaps
are interchanged,the new balance point is:
A. ( 64.4 mathrm{cm} )
B. ( 56 mathrm{cm} )
c. 41.2 ст
D. ( 56.7 mathrm{cm} )
12
88In the given figure, the current in the cell is
A . 33 A
в. 3.3 А
c. 0.33 A
D. 3.32 A
12
89Is it safe for an electrician to carry out
electrical repairs outdoors during heavy downpour ? Explain
12
90The amount of charges that passes any section of the conductors in one second
is called:
A. current
B. power dissipation
c. electromotive force
D. internal resistance
12
91Electromotive force of a battery
represents
( A cdot ) force
B. energy
C. electric potential energy per unit charge
D. current
12
92The length of a given cylindrical wire is increased by ( 100 % . ) Due to the consequent decrease in diameter the
change in the resistance of the wire will be :-
A . 300%
B . 200%
( c cdot 100 % )
D. 50%
12
93A carbon filament has resistance of 120
( Omega ) at ( 0^{0} C . ) The resistance of a copper
filament connected in series with
carbon so that the combination has
same resistance at all temperatures
must be
( alpha ) of carbon ( =-7 times 10^{-4} /^{0} C ; alpha ) of
( operatorname{copper}=4 times 10^{-3} /^{0} C )
A . ( 120 Omega )
B. 21Omega
( c cdot 60 Omega )
D. 210Omega
12
94For the given potentiometer circuits,
potential gradient is ( 0.025 V / m ) and the
ammeter reading is 0.1 A. Now, when
terminals 1 and 2 are connected
balance point is obtained at ( 40 mathrm{cm} ). Also
when terminals 1 and 3 are connected
balance point in obtained at ( 100 mathrm{cm} ). If
( 3 R=k X, ) then the value of ( k ) will be
12
95Three identical resistors each of
resistance ( R ) are connected to an ideal
cell of voltage ( V ) as shown. Total power
dissipated in all three resistors is:
( A cdot frac{3 V^{2}}{2 R} )
( B cdot frac{3 V^{2}}{B} )
c. ( frac{V^{2}}{3 R} )
D. ( frac{2 V^{2}}{3 R} )
12
96Three resistors are connected as shown
in the diagram.

Through the resistor 5 ohm, a current of
1 ampere is flowing.
(i) What is the current through the other
two resistors?
(ii) What is the p.d. across ( A B ) and ( A C ? )
(iii) What is the total resistance?

12
97If the length of the wire is doubled, then the specific resistance will be :-
( mathbf{A} cdot ) two times
B. (1/2) times
c. four times
D. same
12
98If two resistors of resistance ( 30 Omega ) and
( 40 Omega ) are connected in parallel across a battery. The ratio of the potential difference across them is
A . 1: 1
B . 2: 1
( c .3: 4 )
D. 4: 3
12
99Fill in the blanks with suitable words
Electrica is a Latin word which means
12
100At what temperature will the resistance of a copper wire become three times its value at ( 0^{0} ) C? [Temperature coefficient
of resistance for copper ( =4 times ) ( left.10^{-3} p e r^{0} Cright]: )
( mathbf{A} cdot 500^{0} C )
B . ( 450^{circ} mathrm{C} )
c. ( 600^{0} C )
D. None of these
12
101Two cells of emf’s ( 1.25 mathrm{V} ) and ( 0.75 mathrm{V} ) having equal internal resistance are connected in parallel. The effective emf is
A . ( 0.75 v )
B. 1.25V
c. ( 2.0 v )
D. 1.0v
E. ( 0.5 v )
12
102Draw the schematic diagram of an electric circuit consisting of a battery of two cells of ( 1.5 mathrm{V} ) each, three resistance
of 5 ohm, 10 ohm and 15 ohm
respectively and a plug key all connected in series.
12
103The two cells are connected in series, in
a potentiometer experiment, in such a
way so as to support each other and to
oppose each other. The balancing lengths in two conditions are obtained as ( 150 mathrm{cm} ) and ( 50 mathrm{cm} ) respectively. The ratio of emf’s of two cells will be
A . 1: 2
B. 2:
c. 1: 4
D. 4:
12
104When 5 V potential difference is applied across a wire of length ( 0.1 mathrm{m} ), the drift speed of electrons is ( 2.5 times 10^{-4} )
( mathrm{m} / mathrm{s} . ) If the electron density in the wire is ( 8 times 10^{28} m^{-3}, ) calculate the resistivity of
the material of the wire.
12
105Equivalent resistance of the system and potential difference across the external resistance in the figure.
A ( . r, )
в. ( r, E )
( c cdot o, E )
‘ ( r, frac{E R}{R+r} )
12
106Assertion
Statement 1:The current density ( bar{J} ) at any point in ohmic resistor is in direction of electric field ( bar{E} ) at that point.
Reason
Statement ( 2: A ) point charge when released from rest in a region having only electrostatic field always moves along electric lines of force.
A. Both Assertion and Reason are correct and Reason is the correct explanation for Assertion
B. Both Assertion and Reason are correct but Reason is not the correct explanation for Assertion
C. Assertion is correct but Reason is incorrect
D. Assertion is incorrect but Reason is correct
12
107The resistance of a wire of cross-section
‘a’ and length ‘l’ is R ohm. The resistance of another wire of the same material
and of the same length but crosssection ‘4a’ will be
( A cdot 4 R )
в. ( frac{R}{4} )
( c cdot frac{R}{16} )
D. 16 R
12
108Three wires of same material are
connected in parallel to a source of emf. The length ratio of the wires is 1: 2: 3 and the ratio of their area of cross
section is 2: 4: 1
Table 1 Table 2 1 T
6: 6: 1
(p) (a)Resistance ratio : 6: 1
(b) ( begin{array}{ll}text { Current ratio } & text { (q) } 1: 6: 6 \ text { Power ratio } & text { (r) } 1: 1: 6 \ & text { (s) None }end{array} )
(c)
( mathbf{A} cdot 1) )
( a-r, b-q, c-p )
B. 2) a-p,b-q,c-r
c. ( 3) a-r ; b-p, c-p )
D. 4 ) a ( -q, b-p, c-r )
12
109Copper has one conduction electron per atom. Its density is ( 8.89 g / m^{3} ) and its
atomic mass is ( 63.54 mathrm{g} / mathrm{mol} ). If a copper wire of diameter ( 1.0 mathrm{mm} ) carries a current
of 2.0 A. What is the drift speed of the electrons in the wire?
A ( cdot 1.9 times 10^{-4} )
В. ( 2.9 times 10^{-4} )
( mathbf{c} cdot 1.9 times 10^{4} )
D. ( 2.9 times 10^{4} )
12
110A battery of emf 2 volt and internal resistance 0.1 ohm is being charged
with a current of 5 ampere. The
potential difference between the two terminals of the batteries is
A ( .2 V )
в. ( 0.5 V )
( c .1 .5 V )
D. 2.5V
12
111What happens to the current in the external circuit when a battery ages?
A. Remain the same
B. Polarize
c. Reverse direction
D. Increase
E. Decrease
12
112Consider a Wheatstone bridge with
resistance and capacitance connected as shown.

Find the condition on the resistance and
the capacitance such that the bridge remains balanced at all times.

12
113When cells are connected in series
greater emf is obtained in the circuit.
A. True
B. False
12
114If in a Wheatstone bridge the battery and Galvanometer are interchanged, the condition for balance
A. is disturbed
B. is not disturbed
c. depends on the internal resistance of the bridge
D. depends on the values of the resistances in the bridge
12
115( boldsymbol{I}-boldsymbol{V} ) graph for a metallic wire at two
different temperatures, ( boldsymbol{T}_{1} ) and ( boldsymbol{T}_{2} ) is a
shown in the figure.

Which of the two temperature is lower
and why?

12
116Assertion
Bending a wire does not effect electrical
resistance
Reason
Resistance of wire is proportional to
resistivity of material
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
117( boldsymbol{R}_{1}, boldsymbol{R}_{2}, boldsymbol{R}_{3} ) are different values of ( boldsymbol{R} )
( mathbf{A}, mathbf{B}, mathbf{C} ) are the null points obtained
corresponding to ( boldsymbol{R}_{1}, boldsymbol{R}_{2} ) and ( boldsymbol{R}_{3} )
respectively. For which resistor, the value of ( X ) will be the most accurate and
why?
( A cdot R_{1} )
B. ( R_{2} )
( c cdot R_{3} )
D. All same
12
118The ( V-I ) graph for a conductor at
temperature ( T_{1} ) and ( T_{2} ) are as shown in
figure. The term ( left(boldsymbol{T}_{mathbf{2}}-boldsymbol{T}_{mathbf{1}}right) ) is
proportional to:
( mathbf{A} cdot cos 2 theta )
B. ( sin 2 theta )
( c cdot cot 2 theta )
D. ( tan 2 theta )
12
119The capacitors ( C_{1}, C_{3}, C_{4}, C_{5} ) shave a
capacitance ( 4 mu F ) each and ( C_{2} )
has capacitance ( 10 mu F ). The effective
capacitance between ( mathrm{P} ) and ( mathrm{Q} ) will be :
( mathbf{A} cdot 8 mu F )
в. ( 6 mu F )
( c .4 mu F )
D. ( 2 mu F )
12
120A lamp of ( 6 mathrm{V} ) and ( 30 mathrm{W} ) is used in a laboratory but the supply is of ( 120 mathrm{V} ) what will be done to make use of the
lamp?
(1) A resistance may be used
(2) A resistance may be used in series with lamp.
(3) The resistance should be of ( 18 Omega )
A. 1,2 and 3 are correct
B. 1 and 2 are correct
c. 1 and 3 are correct
D. 2 and 3 are correct
12
121When two same conducting rod are
kept at different temperature,
A. theirs resistivity will be different
B. their resistivity will be same
c. resistivity doesn’t’ depend on temperature
D. none of the above
12
122For the given circuit diagram; the
equivalent resistance across battery is :
( A .5 Omega )
B. ( 10 Omega )
( c .20 Omega )
D. ( 15 Omega )
12
123A piece of copper and another of
germanium are cooled from room temperature to ( 77 mathrm{K} ), the resistance of :
A. each of them increases
B. each of them decreases
c. copper decreases and germanium increases
D. copper increases and germanium decreases
12
124The current in a metallic conductor is
plotted against voltage at two different
temperatures ( T_{1} ) and ( T_{2} . ) Which is
correct
( A cdot T_{1}>T_{2} )
В ( cdot T_{1}<T_{2} )
( c cdot T_{1}=T_{2} )
D. None
12
125Three resistances are connected to form
a ( T ) -shape as shown in the figure. Then
the current in the ( 4 mathrm{K} ) resistor is :
A. ( 0.93 mathrm{mA} )
B. ( 1.42 mathrm{mA} )
c. ( 2.5 mathrm{mA} )
D. 1.57 m
12
126A metallic block has no potential difference applied across it, then the mean velocity of free electrons at absolute temperature T is
A. Proportional to ( T )
B. Proportional to ( sqrt{T} )
c. zero
D. Finite but independent of ( T )
12
127A battery of e.m.f. ( 6.0 ~ V ) and negligible
internal resistance is connected to a
network of resistors and a voltmeter, as
shown in Fig.

Resistor ( Y ) has a resistance of ( 24 Omega ) and
resistor ( Z ) has a resistance of ( 32 Omega )
The resistance ( R_{X} ) of the variable
resistor ( X ) is adjusted until the
voltmeter reads ( 4.8 mathrm{V} )
Calculate:
The current in resistor ( Z )
current ( = ) ( boldsymbol{A} )

12
128Figure shows a uniformly charged
hemispherical shell. The direction of
electric field at point ( p, ) that is off-
centre (but in the plane of the largest
circle of the hemisphere), will be along
B. pb
( c cdot p c )
D. pd
12
129When a current ( I ) is set up in a wire of
radius ( r, ) the drift velocity is ( v_{d} . ) If the
same current is set up through a wire of radius ( 2 r, ) the drift velocity will be
A . ( 4 v_{d} )
в. ( 2 v_{d} )
c. ( frac{v_{d}}{2} )
D. ( frac{v_{d}}{4} )
12
130A cell can be balanced against ( 110 mathrm{cm} ) and 100
( mathrm{cm} ) of potentiometer wire, respectively with and
without being short circuited through a resistance of 10 . Its internal resistance
is –
A. 2.0 ohm
B. zero
c. 1.0 ohm
D. 0.5 ohm
12
131A ( 10 m ) long uniform metallic write
having a resistance of ( 20 Omega ) is used as a potentiometer wire. This wire is
connected in series with another
resistance of ( 480 Omega ) and a battery of emf ( 5 V ) having negligible internal resistance. If an unknown emf e is
balanced across ( 6 m ) of the
potentiometer wire, calculate:
(i) The potential gradient across the potentiometer wire.
(ii) The value of the unknown emf e.
12
132AB ia a potentiate wire of length ( 100 mathrm{cm} )
and is resistance is ( 10 Omega ). It is connected
in series with a resistance ( boldsymbol{R}=mathbf{4 0 Omega} )
and a battery of emf ( 2 mathrm{V} ) and negligible
internal resistance. If a source of
unknown potentiate wire, the value of ( mathrm{E} )
is:
( A cdot 0.8 V )
B. ( 1.6 v )
c. ( 0.06 mathrm{v} )
D. ( 0.16 mathrm{v} )
12
133A uniform copper wire carries a current
( boldsymbol{i} ) amperes and has ( boldsymbol{p} ) carriers per metre.
The length of the wire is ( l ) metres and its
cross-section area is s metre. If the
charge on a carrier is ( q ) coulombs, the
drift velocity in ( m s^{-1} ) is given by
( mathbf{A} cdot i / l s q )
( mathbf{B} cdot i / p s q )
( mathbf{c} cdot p s q / i )
( mathbf{D} cdot i / p s l q )
12
134A table lamp of power 60 W consumed 9 (commercial) units of electricity in the month of April. For how many hours per day, on an average, was the lamp in
use?
( A cdot 1 h )
в. ( 3 h )
( c .5 h )
D. ( 6 h )
12
135The resistance of a bulb filament is 100
( Omega ) at a temperature of ( 100^{0} mathrm{C} ). If its temperature coefficient of resistance be 0.005 per ( ^{0} mathrm{C} ), its resistance will become ( 200 Omega ) at a temperature of :
A ( cdot 300^{0} mathrm{C} )
B. ( 400^{circ} mathrm{C} )
( c cdot 500^{0} c )
D. 200^
12
136The equivalent resistance between ( A )
and B is
( A cdot R )
в. ( frac{R}{2} )
( c .2 R )
D. None of these
12
137Four cells each of emf ( 1.9 mathrm{V} ) and the
internal resistance ( 1 Omega ) are connected to
an external resistance of 18 Omega as shown in the figure. Find the terminal potential difference of this combination
12
138A cell of emf ( ^{prime} E^{prime} ) and internal resistance
( r^{prime} ) draws a current ( ^{prime} I^{prime} . ) Write the relation
between terminal voltage ( ^{prime} V^{prime} ) in terms
of ( boldsymbol{E}, boldsymbol{I} ) and ( boldsymbol{r} )
12
139A galvanometer, together with an unknown resistance in series, is connected across two identical
batteries of each ( 1.5 mathrm{V} ). When the
batteries are connected in series, the
galvanometer records a current of ( 1 A )
and when the batteries are connected in
parallel, the current is ( 0.6 A ), then the
internal resistance is ( 1 / x^{prime} ) Omega. What is
the value of ( x ) ‘?
12
140Derive the expression to find the unknown resistance in the balanced
condition of wheastone bridge.
12
141The resistance of carbon filament at
( 0^{0} C ) is ( 104 Omega . ) It is connected in series to
an iron wire. The temperature coefficient of resistivity of carbon and
iron are -0.0003 and +0.0052 per degree Celsius respectively. What must be the resistance of iron wire so that the
combined resistance does not change with temperature?
A . 15
B. 6
c. 1.5
D. 156
12
142Wires ( A ) and ( B ) are made from the same
material. Wire A has length 12m and weight 50 g, while wire ( B ) is 18 m long and weighs 40 g. Then the ratio ( left(R_{A} / R_{B}right) ) of their resistances will be :
( A cdot 16 / 45 )
B. 415
( c cdot 8 / 15 )
D. 419
12
143If the voltmeter reads ( 0.21 mathrm{V} ) and the
ammeter reads ( 0.1 A ), the resistance of
the ammeter is (in ohm)
A. 0.0
в. 0.15
( c cdot 0 . )
D. o.
12
144A student is asked to connected four
cells of e.m.f of ( 1 mathrm{V} ) and internal
resistance 0.5 ohm in series with an
external resistance of 1 ohm. But one
cell is wrongly connected by him with its terminal reversed. the current in the
circuit is
A ( cdot frac{1}{3} A )
в. ( frac{2}{3} A )
c. ( frac{3}{4} )
D. ( frac{4}{3} )
12
145In a circuit two or more cells of the
same e.m.f are connected in parallel in
order to:
A. increase the P.D across a resistance in the circuit
B. decrease the P.D across a resistance in the circuit
C. facilitate drawing more current from the battery system
D. change the e.m.f across the system of batteries
12
146A cell having EMF E and internal resistance ( r ) is connected to a load ( R )
Find the value of ( R ) such that power dissipated by the cell is maximum
12
147Ohm’s law is valid for
A. gases only
B. liquids only
C. both liquids and gases
D. metallic conductors
12
148The values of current I flowing in a given resistor for the corresponding values of potential difference V across the resistor are given below –
|(amperes) 2
( V(v text { olts }) ) 1. 6
. 6 3.4 6.7
Plot a graph between ( mathrm{V} ) and ( mathrm{I} ) and
calculate the resistance of that resistor.
12
149Each of the six ideal batteries of emf
( 20 V ) is connected to an external
resistance of ( 4 Omega ) as shown in the figure.
The current through the resistance is
( mathbf{A} cdot 6 A )
в. ( 3 A )
( c .4 A )
D. ( 15 A )
12
150Kirchhoff’s rules are very useful for analysis of electrical circuits. State Kirchhoff’s junction rules.12
151The magnetic flux through a coil perpendicular to its plane and directed into paper is varying according to the relation ( phi=left(2 t^{2}+4 t+6right) m W b ). The
emf induced in the loop at ( t=4 s ) is
( mathbf{A} cdot 0.12 V )
в. 2.4V
c. ( 0.02 V )
D. ( 1.2 V )
12
152If four resistances are connected as
shown in the fig. between ( A ) and ( B ), the
effective resistance is:
A . ( 3 Omega )
B. ( 1 Omega )
c. ( 2.4 Omega )
D. 25
12
153Quantity of heat produced by a conductor is directly proportional to in the conductor.
A. The time of current flow
B. The resistance
c. The Square of magnitude of current
D. All
12
154Copper contains ( 8.4 times 10^{28} ) free
electrons/ ( m^{3} ). A copper wire of crosssectional area ( 7.4 times 10^{-7} m^{2} ) carries a
current of 1 A. The electron drifts speed
is approximately:
( mathbf{A} cdot 10^{-8} m / s )
B. ( 10^{-3} mathrm{m} / mathrm{s} )
c. ( 1 m / s )
D. ( 10^{-4} mathrm{m} / mathrm{s} )
12
155A battery of ( V ) voltage is connected
across the potentiometer wire ( boldsymbol{A} boldsymbol{C} ) of
total resistance ( R_{0} ) as shown. Calculate
the potential across the resistance ( boldsymbol{R} ) if
the sliding contact point ( B ) is exactly at
the middle of the potentiometer wire.
( A )
в. ( frac{4 V R_{0}}{2 R_{0}+R} )
c. ( frac{2 V R}{R_{0}+4 R} )
D. ( frac{4 V R_{0}}{R_{0}+2 R} )
12
156( P=frac{V^{2}}{R} ) is applied when
A. Current is constant
B. Potential difference is constant
c. Resistance is constant
D. None
12
157What is a potential meter explain its principal
(a)Explain how it can be used to compare the emf of two cells
(b)Explain how it can be used to determine the internal resistance of a
cells.
12
1581) State the law of magnetism.
2) State the law of charges.
3) What happens when a straw is rubbed with a sheet.
12
159A car bulb connected to a 12 volt battery
draw 2 A current when glowing. What is the resistance of the filament of the
bulb?
A . ( 3 Omega )
в. ( 6 Omega )
( c .9 Omega )
D. 24
12
160A part of circuit with current is shown.
The value of ( I ) is :
A ( .1 A )
в. ( 2 A )
( c .4 A )
D. zero
12
161What is the resistance between ( P ) and
Q?
( A cdot frac{3}{4} s )
B. ( frac{4}{3} )
c. ( frac{16}{3} )
D. Infinity
12
162What is the formula for electric power?
A ( cdot P=I^{2} R t )
B . ( P=frac{w}{t} )
c. ( P=V I times t )
D. ( P=v Q )
12
163In a Wheatstone bridge if the battery and galvanometer are interchanged then the deflection in galvanometer will:
A. Change in previous direction
B. Not change
c. change in opposite direction
D. None of these
12
164An electric cell does 5 joules of work in carrying 10 -coulomb charge around the closed circuit. The electromotive force
of the cell is :
A . 2 volt
B. 0.5 volt
c. 4 volt
D. 1 volt
12
165A resistance of ( R Omega ) draws a current from
a potentiometer. The potentiometer has a
total resistance ( R_{0} Omega . ) A voltage V is
supplied to the potentiometer. The
voltage across ( mathrm{R} ) when the sliding contact
is in the middle of the potentiometer is:
A ( cdot frac{2 V R}{4 R_{0}+R} )
В. ( frac{4 V R}{R_{0}+R} )
( mathbf{c} cdot frac{V R}{R_{0}+4 R} )
D. ( frac{2 V R}{R_{0}+4 R} )
12
166A particular resistance wire has a resistance of 3.0 ohm per metre. The total resistance of three lengths of this wire each ( 1.5 mathrm{m} ) long, joined in parallel
will be :
A ( .2 .5 Omega )
в. 3 Omega
c. ( 4.5 Omega )
D. ( 1.5 Omega )
12
167In the circuit shown in figure, the
current through
A. The ( 3 Omega ) resistor is ( 1.00 A )
B. The ( 3 Omega ) resistor is 0.25 A
C. The ( 4 Omega ) resistor is ( 0.50 A )
D. The ( 4 Omega ) resistor is ( 0.25 A )
12
168In a potentiometer of wire length ( l ), a cell of emf ( V ) is balanced at a length ( frac{l}{3} ) from the positive of the wire. For another cell
of emf ( 1.5 V, ) the balancing length
becomes
A ( cdot frac{l}{6} )
B. ( frac{l}{2} )
c. ( frac{l}{3} )
D. ( frac{2 l}{3} )
E ( cdot frac{4 l}{3} )
12
169In the circuit shown below in Fig.
the value of ( x ) if the equivalent
resistance between ( A ) and ( B ) is ( 4 Omega ) will
be:
( A cdot 2 Omega )
B. ( 1 Omega )
c. ( 1.5 Omega )
D. ( 3 Omega )
12
170The electric field ( mathrm{E} ), current density and conductivity ( sigma ) of a conductor are
related as
A ( . sigma=E / J )
В . ( sigma=J / E )
( mathrm{c} cdot sigma=J E )
D. ( sigma=1 / E )
12
171In the following circuit, the battery ( boldsymbol{E}_{mathbf{1}} )
has an emf of ( 12 V ) and zero internal
resistance while the battery ( E ) has emf
of 2 volt. If the galvanometer ( G ) reads
zero, then the value of the resistance ( boldsymbol{X} )
in ohm is
A . 10
в. 100
c. 500
D. 200
12
172A uniform wire of resistance ( 100 Omega ) its
melted and made in the form of uniform
wire, whose length is double that of the original. The resistance of the new wire
is
A ( .200 sqrt{2} Omega )
B. ( 800 Omega )
c. ( 200 Omega )
D. ( 400 Omega )
12
173The diagram shows a resistor connected to a cell of e.m.f. ( 2 V ) How
much heat energy is produced in the resistor in six seconds?
A ( .2 .5 . )
в. 4.8 .
( c cdot 10 J )
D. ( 60 . )
12
174Figure shows a balanced Wheatstone
net. Now, it is disturbed by changing ( mathrm{P} )
to ( 11 omega ).Which of the following steps will
not bring the bridge to balance again?
A. Increasing R by ( 2 omega )
B. Increasing S by ( 20 omega )
C. Increasing Q by ( 10 omega )
D. Making product ( R Q=2200left(omega^{2}right) )
12
1751 ampere current is equivalent to
( mathbf{A} cdot 6.25 times 10^{18} ) electrons ( s^{-1} )
B. ( 2.25 times 10^{18} ) electrons ( s^{-1} )
C ( .6 .25 times 10^{14} ) electrons ( s^{-1} )
D. ( 2.25 times 10^{14} ) electrons ( s^{-1} )
12
176The value of capacitance of capacitors
shown in above diagram are ( C_{1}= )
( boldsymbol{C}_{2}=boldsymbol{C}_{3}=boldsymbol{C}_{4}=boldsymbol{8} boldsymbol{mu} mathbf{C} ; boldsymbol{C}_{5}=mathbf{1 0} boldsymbol{mu} boldsymbol{C} )
The equivalent capacitance between
and Q is:
( A cdot 8 mu F )
B. ( 24 mu F )
( c cdot 16 mu F )
D. ( 15 mu F )
12
177Find odd man out
Plastic, Rubber, Glass, Silver
A . Glass
B. Rubber
c. Silver
D. Plastic
12
178Which is the expression for resistivity of a wire of length ( l ) and cross-section area
A?
A ( cdot rho=frac{R l}{A} )
B. ( rho=frac{R A}{l} )
( c cdot rho=frac{A}{R l} )
D. ( rho=frac{R A}{l^{2}} )
12
179A cell of E.M.F. E and internal resistance
supplies currents for the same time through external resistance ( boldsymbol{R}_{1} ) and ( boldsymbol{R}_{2} )
respectively. If the heat produced in both cases is the same then the internal
resistance is
A ( cdot 1 / r=1 / R_{1}+1 / R_{2} )
B. ( r=left(R_{1}+R_{2}right) / 2 )
( mathbf{c} cdot r=left(R_{1} R_{2}right) )
D. ( r=R_{1}+R_{2} )
12
180In the circuit shown in Figure. What
must the emf ( epsilon ) of the battery be in
order for a current of ( 2.00 A ) to flow
through the ( 5.00 V ) battery? Is the
polarity of the battery correct as shown?
12
1812. In a meter bridge experiment, the null point is obtained
at 20 cm from one end of the wire when resistance X
is balanced against another resistance Y. If X <Y, then
where will be the new position of the null point from the
same end, if one decides to balance a resistance of 4X
against Y?
(a) 50 cm
(b) 80 cm
(c) 40 cm
(d) 70 cm (AIEEE 2004)
12
182A superconductor has ( T_{C}(0)=100 K )
When a magnetic field of 7.5 Tesla is
applied, its ( T_{c} ) decreases to 75 K. For this material one can definitely say that
when
A ( cdot B=5 ) Tesla, ( T_{c}(B)=80 K )
B. ( B=5 ) Tesla, ( 75 K<T_{c}(B)<100 K )
c. ( B=10 ) Tesla, ( 75 K<T_{c}<100 K )
D. ( B=10 ) Tesla, ( T_{c}=70 K )
12
183n identical cells are joined in series with its two cells ( A ) and ( B ) in the loop with reversed polarities. EMF of each shell is ( mathrm{E} ) and internal
resistance r. Potential difference across
cell ( A ) or ( B ) is:
A ( cdot frac{2 E}{n} )
В ( cdot 2 E mid 1-frac{1}{n} )
c. ( frac{4 E}{n} )
D. ( 2 E mid 1-frac{2}{n} )
12
184The current in the primary circuit of a
potentiometer is ( 0.2 mathrm{A} ). The specific resistance and cross section of the
potentiometer wire are ( 4 times 10^{-7} ) ohm
metre and ( 8 times 10^{-7} m^{2} ) respectively. The
potential gradient will be equal to:
A. ( 0.1 mathrm{V} / mathrm{m} )
B. ( 0.2 vee / mathrm{m} )
c. ( 1 mathrm{v} / mathrm{m} )
D. ( 0.5 vee / ) m
12
185The terminal potential difference of a
cell is equal to the emf of the cell when:
A. The cell is an open circuitt
B. The internal resistance of the cell is zero
c. The load resistance ( R ) is much greater than the internal resistance ( r )
D. All are true
12
186Two wires are as follows. The
resistivities, lengths and radii are in the ratio 2: 3,3: 5 and 2: 7 respectively
Their resistances are in the ratio of
A . 49: 10
B. 7: 2
( c cdot 2: 4 )
D. 1: 2
12
187A point charge of ( q ) mass ( m ) is placed at center of a fix ring of charge ( Q ) and radius ( R ) what is the
minimum velocity should be given by ( q ) so they would reach far away from ring.
A ( cdot frac{Q q}{5-sqrt{5}} )
в. ( frac{Q q}{sqrt{5}-1} )
c. ( sqrt{frac{Q q}{2 varepsilon varepsilon R m}} )
D. ( frac{2 q}{5-sqrt{5}} )
12
188A cell of e.m.f. ( mathrm{E} ) and internal resistance
is connected in series with an external
resistance nr then the ratio of the
terminal potential difference to E.M.F. is
A ( cdot 1 / n )
B. ( 1 / n+1 )
( c cdot n / n+1 )
D. ( n+1 / n )
12
189In a meter-bridge, the balancing length from the left end when standard
resistance of 1 is in right gap is found
to be ( 20 mathrm{cm} ). The value of unknown
resistance is
A ( .0 .25 Omega )
B. ( 0.5 Omega )
( c .0 .4 Omega )
D. 4Omega
12
190A current is divided into two resistors
connected in parallel according to Kirchhoff’s law, then the heat produced in the combination is
A. zero
B. Cannot be predicated
c. Minimum
D. Maximum
12
191Two cells ( A ) and ( B ) of emf ( 2 V ) and ( 1.5 vee )
respectively, are connected as shown in
figure through an external resistance
10 ( Omega ). the internal resistance of each cell
and is ( 5 Omega . ) The potential difference ( boldsymbol{E}_{boldsymbol{A}} )
and ( E_{B} ) across the terminals of the cells
A and B respectively are:
( mathbf{A} cdot E_{A}=2.0 V cdot E_{B}=1.5 V )
B ( . E_{A}=2.125 V, E_{B}=1.375 V )
( mathbf{c} cdot E_{A}=1.875 V, E_{B}=1.625 V )
D ( . E_{A}=1.875 V, E_{B}=1.375 V )
12
192Calculate the total power of 2 fans, if each of them draws a current of ( 5 A ) at a
p.d of ( 200 V )
A . ( 2000 omega )
в. ( 1000 V )
( c .250 omega )
D. 2
12
193Four resistors are connected as shown
in figure. A ( 6 V ) battery of negligible
resistance is connected across
terminal ( boldsymbol{A C} ). The potential difference
( operatorname{across} ) terminals ( B ) and ( D ) will be :
A . ( 0 V )
в. ( 1.5 V )
( c .2 V )
D. ( 3 V )
12
194How many electrons constitute a
current of one microampere?
( mathbf{A} cdot 6.25 times 10^{6} )
B. ( 6.25 times 10^{12} )
( mathbf{C} cdot 6.25 times 10^{9} )
D. ( 6.25 times 10^{15} )
12
195The resistance ( boldsymbol{R}_{1} ) and ( boldsymbol{R}_{2} ) are joined in parallel and a current is passed so that the amount of heat liberated is ( boldsymbol{H}_{1} ) and
( H_{2} ) respectively. The ratio ( frac{H_{1}}{H_{2}} ) has the
value
A ( cdot frac{R_{2}}{R_{1}} )
в. ( frac{R_{1}}{R_{2}} )
c. ( frac{R_{1}^{2}}{R_{2}^{2}} )
D. ( frac{R_{2}^{2}}{R_{1}^{2}} )
12
196Assertion: The resistance of a
milliammeter is greater than that of
ammeter

Reason: Shunt resistance in case of
a milliammeter is more than that of
ammeter
A. Both (A) and (R) are true and
(R) is the correct explanation of A
B. Both (A) and (R) are true but (R) is not the correct explanation of A
c. (A) is true but (R) is false
D. (A) is false but (R) is true

12
197Assertion
When current through a bulb decreases by ( 0.5 %, ) the glow of bulb decreases by
( 1 % )
Reason
Glow (Power) which is directly proportional to square of current.
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 incorrect
12
198Statement-1: When two conducting wires of different resistivity having same cross section area are joined in
series, the electric field in them would
be equal when they carry current

Statement-2: When wires are in series
they carry equal current
A. Statement-1 is true and Statement-2 is correct explanation for Statement- –
B. Statement-1 is true and Statement-2 is NOT the correct explanation for Statement-
c. Statement-1 is true, Statement-2 is false
D. Statement-1 is false, Statement-2 is true

12
199The force between two electrons when
placedair is equal to 0.5 times the weight of an electrons find the distance between two electrons (masselectron
( left.=mathbf{9 . 1} times mathbf{1 0}^{-mathbf{3 1}} mathbf{k g}right) )
A . 7.2 m
B. 72cm
c. 72 m
D. 720m
12
200Figure below shows a portion of an electric circuit with the currents in
ampere and their directions. The
magnitude and direction of the current
in the portion ( boldsymbol{P} boldsymbol{Q} ) is:
( A cdot 0 A )
B. ( 3 A ) from ( P ) to ( Q )
( c .4 A ) from ( Q ) to ( P )
D. ( 6 A ) from ( Q ) to ( P )
12
201Define the following:
(a) 1 volt ( P D )
(b) Electric power
12
202What is the reason for using Tungsten as a filament in electric bulb?12
203Dimension of temperature coefficient ( alpha )
is
12
204Draw the ( V-I ) characteristies of an
LED. state two advantages of LED lamps over conventional incandescent lamps.
12
205Value of Current i in the following
circuit is :-
A . 13 A
B. 12 A
( c cdot 9 A )
D. None of these
12
206The electric field intensity ( E, ) current
density ( J ) and specific resistance ( k ) are related to each other through the relation
( A cdot E=frac{J}{k} )
в. ( E=J k )
c. ( _{E}=frac{k}{J} )
D. ( k=J E )
12
207When a current of ( 0.5 A ) is passed
through two resistors in series, the potential difference between the ends
of the series arrangement is ( 12.5 % . ) On connecting them in parallel and passing a current of ( 1.5 A ), the potential difference across them is ( 6 V ). The two
resistances, in ohms, are
( A cdot 5,20 )
B. 5, 15
c. 5,10
D. 15,20
12
208The equivalent resistance between the points ( x ) and ( y ) of the circuit. If each resistance is 25 ohm is
( A cdot 25 Omega )
B. 1000
( c .50 Omega )
D. 12.5Omega
12
209n identical cells, each of emf ( varepsilon ) and
internal resistance ( r, ) are joined in
series to form a closed circuit. One cell
( A ) is joined with reversed polarity. The potential difference across each cell, except ( A ), is
A ( cdot frac{2 varepsilon}{n} )
в. ( frac{n-1}{n} )
c. ( frac{n-2}{n} )
D. ( frac{2 n}{n-2} )
12
210In the circuit shown in figure, ( boldsymbol{E}_{1}= )
( mathbf{3} boldsymbol{V}, boldsymbol{E}_{2}=mathbf{2} boldsymbol{V}, boldsymbol{E}_{3}=mathbf{1} boldsymbol{V} ) and ( boldsymbol{r}_{mathbf{1}}=boldsymbol{r}_{mathbf{2}}= )
( r_{3}=1 o h m )
(a) Find the potential difference
between the points ( A ) and ( B ) and the
currents through each branch.
(b) If ( r_{2} ) is short circuited and the point
( A ) is connected to point ( B ) through a
resistance ( R, ) find the currents through
( boldsymbol{E}_{1}, boldsymbol{E}_{2}, boldsymbol{E}_{3} ) and the resistor ( boldsymbol{R} )
12
211( mathbf{A} )
( 4 Omega(text { or } 4 text { ohm }) ) wire and ( a 2 Omega ) (or 2
ohm)wire are connected in parallel. ( mathbf{A} )
current of ( 3 A ) passes through the wires. How much current passes through the 2
( Omega(text { or } 2 text { ohm }) ) wire?
( A cdot 2 A )
B. 4A
( c cdot 6 A )
D. 8A
12
212Statement 1: The drift speed of electrons
in metals is small (in the order of a few
( m m / s) ) and the charge of an electron is also very small ( left(1.6 times 10^{-19} Cright), ) yet we
can obtain a large current in a metal.
Statement 2: At room temperature, the thermal speed of electrons is very high
(about ( 10^{7} ) times the drift speed)
A. Statement 1 is True, Statement 2 is True; Statement 2 is a correct explanation for Statement 1
B. Statement 1 is True, Statement 2 is True; Statement 2 is not a correct explanation for statement
c. Statement 1 is True; Statement 2 is False
D. Statement 1 is False; Statement 2 is True
12
213( N ) cells, each of emf ( E ) and internal
resistance ( r, ) are connected in a closed
ring so that the positive terminal of each cell is joined to the negaive terminal of the next cell as shown in the
adjoining diagram. Any two points of this ring are connected through an
external resistance ( R ). Find the current
( operatorname{in} R )
12
214Two charges each q nC. are placed at two vertices of an equilaterial triangle of side ( 1 mathrm{m} ). The filed at the other vertex
is
A ( cdot sqrt{2} q )
B. ( 9 sqrt{3} q )
c. ( frac{sqrt{3} q}{10} )
D. ( frac{9 q}{sqrt{3}} )
12
215Assertion: The drift velocity of electrons in a metallic wire will decrease, if the
temperature of the wire is increased.
Reason: On increasing temperature, conductivity of metallic wire decreases.
A. Both (A) and (R) are true and
(R) is the correct explanation of
B. Both (A) and (R) are true but (R) is not the correct explanation of A
c. (A) is true but (R) is false
D. (A) is false but (R) is true
12
216A coil made of insulated copper wire is
connected to a galvanometer. What will
happen if a bar magnet is kept close to the wire ?
outside opposite
12
217Find out the current flowing through
resistor ( boldsymbol{R}_{1} )
12
218Calculate the power used in the ( 2 Omega )
resistor in each of the following circuits:
(i) a ( 6 V ) battery in series with ( 1 Omega ) and ( 2 Omega )
resistors, and (ii) a ( 4 V ) battery in parallel with ( 12 Omega ) and ( 2 Omega ) resistors.
12
219The resistance of a conductor at ( 20^{circ} mathrm{C} ) is
3.15 ohm and at ( 100^{circ} mathrm{C} ) is 3.75 ohm.
Determine the temperature co-efficient of resistance of the conductor. What will
be the resistance of the conductor at 0
( ^{o} C ? )
12
220The current flowing in the primary circuit of potentiometer is ( 2 A ) and the resistance of its wire is ( 0.2 Omega / m . ) If a one ohm standard coil gets balanced at ( 250 mathrm{cm} ) length of the wire, then the
current flowing in the coil will be
A . ( 0.1 mathrm{A} )
B. 1A
c. ( 1.5 mathrm{A} )
D. 0.05A
12
221A source of constant potential
difference is connected across a
conductor having irregular cross section as shown,then
A. Electric field intensity at ( P ) is greater than that at ( Q )
B. rate of electrons crossing per unit area of cross section at ( P ) is less than that at ( Q )
c. the rate of generation of heat per unit length at ( P ) is greater than at ( Q )
D. mean kinetic energy of free electrons at ( P ) is greater than that at ( Q )
12
222A wire has resistance of ( 12 Omega ). It is cut
into two parts and both halve are connected in parallel. The new resistance is
A . ( 3 Omega )
в. ( 1.5 Omega )
c. ( 12 Omega )
D. ( 6 Omega )
12
223A current of ( I ) ampere flows through a resistance ( R ) when connected across a
cell of emf ( E ) and internal resistance ( 1 Omega )
When ( R ) is increased by ( 50 % ), the
current through the circuit is ( 0.8 A . ) The
value of ( boldsymbol{R} ) is :
A . ( 1 Omega )
B. ( 1.5 Omega )
( c .2 Omega )
D. 4Omega
12
224Define temperature coefficient of
resistance.
12
225The minimum resistance that can be
obtained by connecting 5 resistance of ( frac{1}{4} Omega ) each is
A ( cdot frac{4}{5} Omega )
в. ( frac{4}{Omega} )
( c .20 Omega )
D. ( 0.05 Omega )
12
226A metallic wire has a resistance of ( 3.0 Omega )
at ( 0^{circ} mathrm{C} ) and ( 4.8 Omega ) at ( 150^{circ} mathrm{C} ). Find the
temperature coefficient of resistance of
its material
12
227Ohm’s law is :
A. ( V I )
B . ( I^{2} R )
( c . I R )
D. ( R^{2} I )
12
228Find the potential at the centre of arrangement having 6 charged particles of ( Q=5 mu C ) each arranged in
the form of a hexagon of side length 0.1
( mathrm{m} )
12
229The power dissipated in the circuit
shown in the figure is 30 watts. The
value of R is
A . ( 20 Omega )
В. ( 5 Omega )
( c .10 Omega )
D. ( 30 Omega )
12
230f power dissipated in the ( 9 Omega ) resistor in
the circuit shown is 36 Watt, the
potential difference across the ( 2 Omega )
resistor is :
A. 2 volt
3. 4 volt
( c .8 ) volt
D. 10 volt
12
231The effective capacitance between ( mathrm{P} ) and
Q of the figure below is :
( C_{1}=C_{3}=C_{4}=C_{5}=10 mu F )
( C_{2}=100 mu F )
A ( .10 mu F )
B. ( 40 mu F )
( c .5 mu F )
D. ( 20 mu F )
12
232All resistance are connected in the
series. The current is flowing through
circuit is ( 2 A ) and battery is of 20 Volts. What is the power dissipated through one of the ( 4 Omega ) :
( A cdot 4 w )
B. 8 w
( c cdot 16 w )
D. 32 ( w )
E. 36
12
233Determine the current drawn from 12
supply with internal resist ( 0.5 Omega ) by
infinite network. Each resistor has ( 1 Omega )
resistance
( A cdot 3 A )
3. 2.7A
( c .3 .7 A )
D. 4.2 A
12
234The relation between potential difference (V) and current (I) was
discovered by :
A. Newton
B. Ampere
( c . ) onm
D. volt
12
235With the usual notations, check if the
following equation ( S_{t}=u+frac{1}{2} a(2 t-1) )
is dimensionally correct or not.
12
236A carbon resistance with color band is
( 200 Omega . ) If red band is replaced by green band then the new resistance is:
( mathbf{A} cdot 500 Omega )
в. 300Omega
c. ( 400 Omega )
D. ( 100 Omega )
12
237Assertion
Potentiometer is used only to compare
potential differences.
Reason
The potentiometer draws current from the voltage source being measured.
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
238Let ( f=50 mathrm{Hz}, ) and ( mathrm{C}=100 mu mathrm{F} ) in an ( mathrm{AC} )
circuit containing a capacitor only. If the peak value of the current in the circuit is ( 1.57 mathrm{A} ) at ( mathrm{t}=0 . ) The expression for the instantaneous voltage across the capacitor will be:
A ( . E=50 sin (100 pi t-pi / 2) )
В. ( E=100 sin (50 pi t) )
c. ( E=50 sin pi t )
D. ( E=50 sin (100 pi t+pi / 2) )
12
239Assertion
When a battery is short-circuited, the
terminal voltage is zero.
Reason
In the situation of a short-circuit, the
current is zero
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
240Assertion
In a Meter Bridge experiment, null point for unknown resistance is measured. Now, the unknown resistance is put
inside an enclosure maintained at a
higher temperature. The null point can be obtained at the same point as before by decreasing the value of the standard resistance. and
Reason
Resistance of a metal increases with
increase in 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. Assertion is incorrect but Reason is correct
12
241State the two Kirchhoff’s rules used in
electric networks. How are there rules
justified?
12
242Blue,green,yellow and yellow is the color band on the resistor,find its resistance?
( mathbf{A} cdotleft(75 times 10^{4}right) Omega pm 5 % )
B . ( left(65 times 10^{4}right) Omega pm 5 % )
C ( cdotleft(52 times 10^{4}right) Omega pm 5 % )
D. ( left(65 times 10^{4}right) Omega pm 10 % )
12
243A metallic conductor of irregular cross-
section is as shown in the figure. A
constant potential difference is applied
across the ends (1) and ( (2) . ) Then
(1)
A. the current at the cross-section ( P ) equal the current at the cross-section ( Q )
B. the electric field intensity at ( P ) is less than that of ( Q )
C. the rate of heat generated per unit time at ( Q ) is greater than that at ( P )
D. the number of electrons crossing per unit area of cross-section at ( P ) is less than that at ( Q )
12
244The unit of e.m.f. of a cell is:
A. dyne
B. volt
c. ampere
D. joule
12
245A bulb of ( 100 mathrm{W}-200 mathrm{V} ) is connected to a
( 160 mathrm{V} ) supply. Find the power consumed.
A. ( 25 mathrm{w} )
B. 64 W
( c cdot 45 w )
D. 20 W
12
246The equivelent resistance between ( A )
and ( B ) is
( ^{A} cdot frac{288}{56} Omega )
В. ( 12 Omega )
( c cdot 8 )
( D )
12
247Which of the following statements are wrong w.r.t the specific resistance of
wire?
This question has multiple correct options
A. It varies with its length
B. It varies with its cross-section
c. It varies with its mass
D. It varies with nature of material
12
248A series-parallel combination of battery consisting of a large number ( N=300 )
of identical cells, each with an internal
resistance ( r=0.3 Omega, ) is loaded with an
external resistance ( boldsymbol{R}=mathbf{1 0} boldsymbol{Omega} ). then, the
number ( n ) of parallel group consisting of an equal number of cells connected in
series at which the external resistance
generates highest thermal power is
A. 3
B. 4
( c .5 )
D. none of the above
12
249Eight identical cells each of potential and internal resistance r are connected
in series to form a closed circuit. An
ideal voltmeter connected across 2 cells
A . 13 E
B. zero
( c cdot 2 E )
D. 10 E
12
250An electron is moving near to a
conducting loop then the induced
current in the loop is-
A . clockwise
B. anticlockwise
c. first anticlockwise and then clockwise
D. no current
12
251Describe Kelvins method to determine
the resistance of galvanometer by using meter bridge.
12
252An electric heater of power 3 kW is used for one minute.Find the energy supply by the heater.12
253Three identical bulbs are connected as
shown in figure. When switch ( S ) is
closed, the power consumed in bulb ( B )
is ( P . ) What will be the power consumed by the same bulb when switch ( S ) is
opened?
( ^{A} cdot frac{9 P}{4} )
в. ( frac{16 P}{9} )
c. ( frac{9 P}{16} )
D. ( frac{4 P}{9} )
12
254A wire of resistance ( 4 Omega ) is stretched to
double its original length. The resistance of the stretched wire would
be
A . ( 2 Omega )
в. ( 4 Omega )
c. ( 8 Omega )
D. ( 16 Omega )
12
(b) Write Kirchhoff’s junction rule.
In the given diagram write the value of
current ( boldsymbol{I} )
12
256The resistance of an object depends on
its :
A. shape
B. material of which it is composed
( c . ) size
D. all of the above
12
257If the length and area of cross-section of a conductor are doubled, then its
resistance will be
A. unchanged
B. halvedd
c. doubled
12
258Null point with ( 1 V ) cell comes out to be ( 55 mathrm{cm} ) and with ( R=10 Omega ) it is ( 50 mathrm{cm} )
What is the internal resistance of the
cell?
A . ( 0.5 Omega )
В. ( 0.4 Omega )
( c .1 Omega )
D. ( 0.2 Omega )
12
259Define the term ‘drift velocity’ of charge
carriers in a conductor and write its
relationship with the current flowing through it.
12
260A potentiometer wire of length ( 1.0 mathrm{m} ) has a resistance of ( 15 Omega ). It is connected to a
( 5 V ) battery in series with a resistance of
5 Omega. Determine the emf of the primary cell which gives a balance point at 60
( mathrm{cm} )
12
261Two square metal plates ( A ) and ( B ) are of
the same thickness and material. The
side of ( B ) is twice that of ( A ). If the
resistances of ( A ) and ( B ) are denoted by ( boldsymbol{R}_{A} ) and ( boldsymbol{R}_{B}, ) Then ( left(frac{boldsymbol{R}_{boldsymbol{A}}}{boldsymbol{R}_{boldsymbol{B}}}right) ) is
( A cdot frac{1}{2} )
B. 2
( c .1 )
( D )
12
262In the experimental set up of metre
bridge shown in the figure, the null
point is obtained at a distance of ( 40 mathrm{cm} )
from A. If a ( 10 Omega ) resistor is connected in
series with ( R_{1}, ) the null point shifts by
10cm. The resistance that should be
connected in parallel with ( left(boldsymbol{R}_{1}+mathbf{1 0}right) boldsymbol{Omega} )
such that the null point shifts back to its initial position is?
A. ( 40 Omega )
в. ( 60 Omega )
( c .20 Omega )
D. ( 30 Omega )
12
263An electric alpole consists or small
charged objects ( A ) and ( B ) of charges ( -q )
and ( +q ) and masses ( m ) and ( 4 m )
respectively. They are connected by a light non -conducting rod of length ( L ) This system is hinged at ( A ) so that it
can rotate in vertical plane. A uniform
electric field of intensity ( boldsymbol{E} ) is applied vertically downward. The rod is released
from horizontal position as shown in figure. The angular velocity of the rod
when the rod becomes vertical is.
A ( cdot sqrt{frac{4 m g+q E}{2 m l}} )
B. ( sqrt{frac{6 m g+q E}{2 m l}} )
c. ( sqrt{frac{8 m g+q E}{6 m l}} )
D. ( sqrt{frac{2 m g+q E}{2 m l}} )
12
264The resistivity of a semiconductor
A. Increases as the temperature increases
B. Decreases as the temperature increases
C. Remains constant even when temperature varies
D. None of the above
12
265If the switch at point ( P ) is opened
(shown in the figure) choose the correct
option
A. the current in ( R_{1} ) would not change
B. the potential difference between point ( X ) and the ground would increas
c. the current provided by the battery would increase
D. the emf produced by the battery (assumed to have internal resistance) would change
12
266State any two possible sources of errors in meter bridge experiment.12
267By increasing the temperature, the specific resistance of a conductor and a
semiconductor
A. decreases for both
B. increases for both
c. increases, decreases
D. decreases, increases
12
268Consider the cylindrical element as shown in the figure. Current flowing the through element is ( I ) and resistivity of
material of the cylinder is ( rho . ) Choose the
correct option out the following
A. Power loss in first half is four times the power loss in second half
B. Voltage drop in first half is twice of voltage drop in second half
c. Current density in both halves are equal
D. Electric field in both halves is equal
12
269The thermo-emf of a copper-constant
couple is ( 40 mu V ) per degree. The smallest temperature difference that can be detected with this couple and
galvanometer of ( 100 Omega ) resistance capable of measuring the minimum
current of ( 1 mu A ) is
A ( cdot 2.5^{circ} mathrm{C} )
B. ( 2^{circ} C )
( mathbf{c} cdot 1.5^{circ} mathrm{C} )
D. ( 1^{circ} mathrm{C} )
12
270How can the current rating of a cell be increased?
A. by increasing friction
B. by increasing voltage
c. by increasing electrostatic
D. cant be increased
12
271A ( 30 V, 90 W ) lamp is to be operated on
a ( 120 V D C ) line. For proper glow, a
resistor of ….. should be connected in
series with the lamp
A . 10
B. 20
c. 30
D. 40
12
272n the circuit shown in the figure, the
( A cdot 0.8 A )
B. 1.2 A
( c cdot 2 A )
D. ( 0.4 mathrm{A} )
12
273The product of resistivity and conductivity of a conductor is constant.
Explain it.
12
274The temperature coefficient of
resistance of platinum is ( boldsymbol{alpha}=mathbf{3 . 9 2} times )
( 10^{-1} K^{-1} ) at ( 20^{circ} C . ) Find the
temperature at which the increase in the resistance of platinum wire is ( 10 % )
of its value at ( 20^{circ} C )
A ( .40 .5^{circ} mathrm{C} )
в. ( 45.5^{circ} mathrm{C} )
c. ( 48.5^{circ} mathrm{C} )
D. ( 43.5^{circ} mathrm{C} )
12
275When we pay for our electricity bill, we are paying for the:
A. charge used.
B. current used
c. power used.
D. energy used
12
276The equivalent resistance of network of
three ( 2 Omega ) resistors can not be
A . 0.67
B. 2Omega
( c .3 Omega )
D. ( 6 Omega )
12
277Six identical resistors are connected as
shown in the figure. The equivalent
resistance will be:
A. Maximum between P and R
B. Maximum between Q and R
c. Maximum between P and Q
D. All are equal
12
278Figure shows a piece of semiconductor pure one) ( mathrm{S} ) in series with a variable
resistors ( mathrm{R} ) and a source of constant
voltage ( V . S ) is heated and the current is
kept constant by adjustment of R. Which of the following factors will decrease during the precess?
1. The drift velocity of the conduction electrons in S.
2. The DC resistors of ( S )
3. The number of conduction electrons
in S.
A. Only 1
B. 1 and 2
c. ( 1,2, ) and 3
D. only
12
279In a metre bridge, the gaps are closed by two resistances ( mathrm{P} ) and ( mathrm{Q} ) and the
balance point is obtained at ( 40 mathrm{cm} )
When ( Q ) is shunted by a resistance of 10
( Omega, ) the balance point shifts to ( 50 mathrm{cm}, ) The
values of ( P ) and ( Q ) arc
A ( cdot frac{10}{3} Omega, 5 Omega )
B. ( 20 Omega, ) 30Omega
c. ( 10 Omega, ) 15Omega
D. ( 5 Omega, frac{15}{2} Omega )
12
280An electric bulb consumes ( 7.2 k J ) of
electrical energy in 2min. What is the power of the electric bulb?
12
281A 50 V d.c power supply is used to charge a battery of eight lead
accumulators, each of emf ( 2 mathrm{V} ) and
internal resistance ( 1 / 8 Omega ). The charging current also runs a motor connected in
series with the battery. The resistance of the motor is ( 5 Omega ) and the steady current supply is 4 A. The mechanical power stored in the motor is
A. ( 80 mathrm{w} )
B. 40 ( w )
( c cdot 64 w )
D. 30 w
12
282What is a free electron?
A. Any electron that is not attached to an ion, atom, or molecule and is free to move under the influence of an applied electric or magnetic field
B. Any electron that is attached to an ion, atom, or molecule and is free to move under the influence of an applied electric or magnetic field
C. Any neutron that is not attached to an ion, atom, or molecule and is free to move under the influence of an applied electric or magnetic field
D. None
12
283Rate of dissipation of Joule’s heat in resistance per unit volume is (symbols have usual meaning)
A ( cdot sigma E )
в. ( sigma J )
( c . J E )
D. None
12
284In the figure, resistivities of two
conductors of same material are ( rho_{1} Omega )
( m ) and ( rho_{2} Omega-m ) respectively. Write the
value of ratio of ( rho_{1} ) and ( rho_{2} )
12
285A free electron in an electric field
A. remains stationary
B. moves from the higher potential to the lower potential
C. moves from the lower potential to the higher potential
D. None
12
286The resistance ( R ) of a conductor varies
with temperature as shown in the given figure. If the relation between ( R ) and ( t ) is
given as,
( boldsymbol{R}_{t}=boldsymbol{R}_{0}left(1+boldsymbol{alpha}+boldsymbol{beta} boldsymbol{t}^{2}right), ) then
A. ( alpha ) and ( beta ) are negative
B. ( alpha ) is positive but ( beta ) is negative
( c cdot alpha ) and ( beta ) are positive
D. ( alpha ) is negative but ( beta ) is positive
12
287In the circuit diagram shown all the
capacitors are in ( mu F . ) The equivalent
capacitance between points ( A ) and ( B ) is ( (operatorname{in} mu F) )
A ( cdot frac{14}{5} )
B. 7.5
( c cdot frac{3}{7} )
D. none of these
12
288Four charges ( +boldsymbol{Q},-boldsymbol{Q},+boldsymbol{Q},-boldsymbol{Q} ) are
placed at the corners of a square taken order. At the centre of the square
A. ( E=0, V=0 )
B. ( E=0, V neq 0 )
c. ( E neq 0, V=0 )
D. ( E neq 0, V neq 0 )
12
289If a rod has resistance ( 4 Omega ) and if rod is
turned as half circle, then the
resistance along diameter is
( mathbf{A} cdot 1.56 Omega )
B . ( 2.44 Omega )
c. ( 4 Omega )
D. 2Omega
12
290The potentiometer is more appropriate
for measuring potential difference than
a voltmeter because
A. the resistance of voltmeter is high
B. the sensitivity of a potentiometer is higher than that of voltmeter
C. the resistance of potentiometer wire is very low
D. the potentiometer does not draw any current from the unknown source of emf
12
291A boy has two spare light bulbs in his drawer. One is marked ( 240 mathrm{V} ) and ( 100 mathrm{W} )
and the other is marked ( 240 mathrm{V} ) and ( 60 mathrm{W} )
He tries to decide which bulb should be
used and why??
A. The 60 W light bulb has more resistance and therefore burns more brightly
B. The 60W light bulb has less resistance and therefore burns less brightly
c. The 100 w bulb has more resistance and therefore burns more brightly
D. The 100 W bulb has less resistance and therefore burns less brightly
12
292An unknown resistance ( R_{1} ) is connected
in series with a resistance of 10 ohm.
This combination is connected to one
gap of a metre bridge, while other gap is
connected to another resistance ( boldsymbol{R}_{2} )
The balance point is at ( 50 mathrm{cm} . ) Now, when the 10 ohm resistance is removed, the balance point shifts to ( 40 mathrm{cm} . ) Then,
the value of ( boldsymbol{R}_{1} ) is
A. ( 60 Omega )
B. 40Omega
c. ( 20 Omega )
D. ( 10 Omega )
12
293The potential difference in open circuit for a cell is ( 2.2 mathrm{V} ). When a ( 4 Omega ) resistor is
connected between its two electrodes
the potential difference becomes ( 2 mathrm{V} ) The internal resistance of the cell will be
A . ( 1 Omega )
B. ( 0.2 Omega )
( c .2 .5 Omega )
D. ( 0.4 Omega )
12
294The resultant resistance between ( A ) and
B is, given the galvanometer is ideal
with resistance 0
A . ( 4 Omega )
B. ( 2 Omega )
( c .1 Omega )
D. ( 10 Omega )
12
295The resistivity of a wire depends on its
A. length
B. area of cross-section
c. material
D. all of the above three factors
12
296An experiment to verify ohm’s law, a conductor of resistance ( R ) is taken
During the experiment, temperature of the conductor increases with the flow of
current. Resistance of the conductor
will
A. Remains same
B. Decrease
c. Increase
D. First increases then decreases
12
297A wire has a resistance of 10 ohm. Its
resistance if it is stretched by one-tenth of its original length is:
A . ( 12.1 Omega )
B. ( 7.9 Omega )
( c cdot 11 Omega )
D. ( 9 Omega )
12
298If temperature is decreased, then
relaxation time of electrons in metals
will
( A ). increase
B. decrrease
C. fluctuate
D. remains constant
12
299Resistance of conductor is doubled
keeping the potential difference across it constant. The rate of generation of
heat will:
A. become one fourth
B. be halved
c. be doubled
D. become four times
12
300The wattage of an electric heater which
draws 5 A current when connected to a
( 220 mathrm{V} ) supply is
12
301Two resistances 6 and 12 ohms are
connected in parallel to a battery of 10 volts. The current in amperes in 12 ohm
resistor is
A . ( 5 / 6 )
B. 6/5
( c cdot 4 / 3 )
D. 3/4
12
302What is the current of ( I_{2} ? )12
303toppr
from point A through point G in the
graphs directly below.
Which of the graphs shows the voltage
from point ( A ) to point ( G ? )
( A cdot A )
B. B
( c cdot c )
( D cdot D )
( E . )
12
304toppr
move in the direction of current and
point of the conductor is plotted against
the distance covered (x). Which of the
following best represents the resulting
Curve?
( mathbf{A} )
( B )
( mathbf{C} )
( D )
12
305A resistance is shown in the figure. Its
value and tolerance are given
respectively by:
( mathbf{A} cdot 27 K Omega, 20 % )
B ( .270 K Omega, 5 % )
( mathbf{c} .270 K Omega, 10 % )
D. ( 27 mathrm{K} Omega, 10 % )
12
306The ( I-V ) characteristics of a metal
wire at two different temperatures ( left(T_{1}right. )
and ( T_{2} ) ) are given in the adjoining
figure. Here, we can conclude that:
( A cdot T_{1}>T_{2} )
в. ( T_{1}<T_{2} )
( c cdot T_{1}=T_{2} )
D ( cdot T_{1}=2 T_{2} )
12
307The emf of a cell is ( varepsilon ) and its internal
resistance is ( r . ) Its terminals are
connected to a resistance ( R ) The
potential difference between the
terminals is ( 1.6 V ) for ( R=4 Omega, ) and ( 1.8 mathrm{V} )
for ( boldsymbol{R}=mathbf{9} boldsymbol{Omega} . ) Then
( mathbf{A} cdot varepsilon=1 V, r=1 Omega )
B. ( varepsilon=2 V, r=1 Omega )
( mathbf{c} cdot varepsilon=2 V, r=2 Omega )
D. ( varepsilon=2.5 V, r=0.5 Omega )
12
308Two resistors, ( boldsymbol{R}_{1} ) and ( boldsymbol{R}_{2}, ) are identical
but the potential difference across ( boldsymbol{R}_{1} )
is half the potential difference across
( R_{2} . ) What is the ratio of the current in
( R_{1} ) to the current in ( R_{2} ? )
A ( cdot frac{1}{4} )
B. ( frac{1}{2} )
c.
D. 2
E . 4
12
309Match the following:
Table – 1
(a) Minimum current will flow through
(b) Maximum current will flow through
(c) Maximum power will be generated across
(d) Minimum power will be generated across
( mathbf{A} cdot a-p ; b-p ; c-q ; d-r )
B ( . a-r ; b-r ; c-p ; d-s )
( mathbf{c} cdot a-q ; b-p ; c-r ; d-q )
D. ( a-s ; b-s ; c-r ; d-q )
12
310If the resistance of a circuit is halved
and the potential difference is kept constant, then the current will become
A. 4 times
B. 8 times
c. double
D. half
12
311Time taken by a 836 Wheater to heat
one litre of water from ( 10^{circ} mathrm{C} ) to ( 40^{circ} mathrm{C} ) is:
A. 50 s
B. 100 s
( c cdot 150 s )
D. 200
12
312What is the current through the resistor
( 6 Omega ) in the circuit shown in figure.
A . ( 10 / 3 ) A
B. ( 5 / 2 ) A
( c cdot 5 / 3 A )
( D cdot 1 / 4 A )
12
313When the resistivity of all pure metals increases, then the temperature will :
A. decrease
B. increase
c. remain constant
D. first decrease and then increase
12
314Three resistors of ( 10 Omega, 15 Omega ) and ( 20 Omega )
are connected in series in a circuit. If
the potential drop across the ( 15 Omega )
resistor is ( 3 V ), find the current in the
circuit, potential drop across ( 10 Omega ) and the net emf of the source used in the
circuit. (Draw the circuit diagram)
12
315Electric heaters used for cooking have the filament or the heating coil on a plate made up of clay because
A. Clay is a bad conductor of heat
B. Clay is a bad conductor of electricity
c. Both ( A & B )
D. None of these
12
316A rectangular metal block has
dimensions ( 3 c m times 1 c m times 1 c m . ) The
ratio of the resistance measured
between the two opposite rectangular faces to that measured between the two square forces of the block is:
A . 1: 3
B. 1: 9
c. 3: 1
D. 9: 1
12
317( 1 W h(text { Watt hour }) ) is equal to
A. ( 36 times 10^{5} J )
B. ( 36 times 10^{4} J )
c. ( 3600 J )
D. ( 3600 J s^{-1} )
12
318An electrical cable of copper has just one wire of radius ( 9 mathrm{mm} ). Its resistance
is ( 5 Omega .6 ) different well-insulated copper wires each of radius ( 3 mathrm{mm} ) replace this single copper wire of the cable. The total resistance of the cable will now be
equal to
A . ( 7.5 Omega )
B. ( 45 Omega )
c. ( 90 Omega )
D. 270Omega
12
319A steady current flows in a metallic
conductor of non-uniform cross-section.
Which of the following quantities is constant along the conductor?
A . Drift speedd
B. current
c. currently density
D. None of these
12
320If a resistance ( R ) is melted and
recasted to half of its length, then the new resistance of the wire will be
A ( cdot frac{R}{2} )
в. ( 2 R )
c. ( R )
D. ( frac{R}{4} )
12
321( mathbf{5 0} boldsymbol{V} ) battery is supplying current of ( mathbf{1 0} ) amp when connected to a resistor. If the
efficiency of battery at this current is 25
%. Then internal resistance of battery
is:-
A . ( 2.5 Omega )
B. ( 3.75 Omega )
c. ( 1.25 Omega )
D. ( 5 Omega )
12
322When a battery connected across a
resistor of ( 16 Omega, ) voltage across the resistor is ( 12 mathrm{V} ). When the same battery
is connected across a resistor of ( 10 Omega )
voltage across it is 11 V. The internal resistance of the battery (in ohm) is :
A ( cdot frac{10}{7} )
B. ( frac{20}{7} )
c. ( frac{25}{7} )
D. ( frac{30}{7} )
12
323n the circuit shown below emf of each
batter y is 5V; and has an internal
resistance of ( 1.0 Omega . ) The current in the
circuit ( left(I_{0}right) ) and the reading in an ideal
voltmeter (V) are
A ( cdot I_{0}=1 A, V=0 )
В . ( I_{0}=5 A, V=0 )
c. ( I_{0}=1 A, V=1 )
D . ( I_{0}=5 A . V=1 )
12
324The electric current flowing through a conductor is directly proportional to the across the two ends of the
conductor.
A. conductance
B. capacitance
c. inductance
D. potential difference
12
325Obtain balancing condition of
Wheatstone’s bridge Kirchoff’s rules electrical circuit.
12
326Calculate the equivalent resistance between the points ( A ) and ( B ) in the given circuit in ohms.
A. 6
в.
( c cdot 2 )
( D )
12
327Two point charges ( q_{1} ) and ( q_{2} ) are placed as shown. Resultant electric field origin is along -y-axis, ( left(frac{boldsymbol{q}_{1}}{boldsymbol{q}_{2}}right) ) equals to:
A ( cdot frac{1}{sqrt{2}} )
B. ( frac{1}{2 sqrt{2}} )
( c cdot sqrt{2} )
( D )
12
328The unit of an electrical parameter
whose formula is ( left[M^{1} L^{2} T^{-3} A^{-2}right] ) is:
A. ohm
B. ampere
c. volt
D. newton
12
329Two wires made of same material have
Iengths in the ratio 1: 2 and their volumes in the same ratio. The ratio of
their resistances is:
A . 4: 1
B . 2: 1
c. 1: 2
D. 1: 4
12
330Find the currents ( I_{1} ) and ( I_{2} ) for the
circuit shown in given figure.
A ( cdot I_{1}=-6 A ) and ( I_{2}=9 A )
B . ( I_{1}=6 A ) and ( I_{2}=9 A )
( mathbf{c} cdot I_{1}=-6 A ) and ( I_{2}=-9 A )
( mathrm{D} cdot I_{1}=-9 A ) and ( I_{2}=6 A )
12
331Six resistors each of ( 10 Omega ) are
connected as shown. Find the
equivalent resistance in ohms between
points ( X ) and ( Y )
12
332The drift velocity of the electron in a
copper wire of length ( 2 mathrm{m} ) under the application of a potential difference of
( 200 mathrm{V} ) is ( 0.5 mathrm{ms}^{-1} ).Their mobility is (in
( left.m^{-2} V^{-1} s^{-1}right) )
( mathbf{A} cdot 5 times 10^{-3} )
B. ( 2.5 times 10^{-2} )
c. ( 5 times 10^{2} )
D. ( 10^{-3} )
12
333If Ohm’s law is presumed to be valid,
then drift velocity ( V_{d} ) and electric field ( E )
are related as
A ( cdot v_{d} propto E^{2} )
B ( cdot v_{d} propto sqrt{E} )
c. ( v_{d} propto E )
D. ( v_{d} propto E_{0} )
12
334Potentiometer measures potential more accurately because
A. it measures potential in open circuitt
B. it uses sensitive galvanometer for null deflection
c. it uses high resistance potentiometer wire.
D. it measures potential in closed circuit
12
335From the observation of Ohm’s law ( 1 rightarrow ) V
graph is drawn here.

From that which points are concluded?
( P: I rightarrow V ) graph is a straight line.
Q: Ratio of V and I remains constant
every time.
R: The electric current in a conductor
increases in same proportion with the increase in voltage
A. Statements P, Q and R are all true
B. Statements Q and R are true
c. Statements P and R are true
D. Statements P and Q are true

12
336The induced current produced in a closed coil is always in nature.
A. strength
B. alternating
c. less
D. primary
12
337AB is a wire of potentiometer with the increase in the value of resistance ( mathrm{R} ),
the shift in the balance point J will be.
A. Towards B
B. Towards A
c. Remains constant
D. First towards B then back towards
12
338Find ( boldsymbol{R} )12
339Which of the following options, which describe the dependence of drift
velocity ( v_{d} ) on electric field ( E, ) obeys
Ohm’s law?
A ( cdot v_{d} propto E )
В ( cdot v_{d} propto E^{2} )
( mathbf{c} cdot v_{d} propto sqrt{E} )
D. ( v_{d}= ) constant
12
340A metal block has dimension ( 10 mathrm{cm} times )
( 5 c m times 2 c m ).the ratio of maximum to
minimum resistance that can be
obtained from it is
( mathbf{A} cdot 25: 1 )
B. 1: 25
( mathbf{c} cdot 10: 3 )
D. 3: 10
12
341An electric circuit contains an
operating heating element and a lit lamp. Which statement best explains why the lamp remains lit when the heating element is removed from the circuit?
A. The lamp and heating element were connected in parallel
B. The lamp has less resistance than the heating element
C. The lamp has more resistance than the heating element
D. The lamp and heating element were connected in series
12
342A negatively charged rod is brought close to two metal spheres which are in
contact with each other, and the
spheres are separated in the presence
of the rod. Then
A. The sphere close to the rod acquires a negative charge and the other sphere acquires a positive charge
B. The sphere close to the rod acquires a positive charge and the other sphere acquires a negative charge
c. Both the spheres will acquire positive charge
D. Both the spheres will acquire negative charge
12
343Potentiometer wire of length ( 1 mathrm{m} ) is connected in series with ( 490 Omega )
resistance and ( 2 mathrm{V} ) battery. If ( 0.2 mathrm{mV} / mathrm{cm} ) is the potential gradient, then resistance of the potentiometer wire is?
A . ( 4.9 Omega )
B. ( 7.9 Omega )
( c .5 .9 Omega )
D. ( 6.9 Omega )
12
344If ( E=16 ) volts, ( r=4 Omega ) and distance of
balance point ( P ) from end ( A ) is ( 90 mathrm{cm} )
then the value of ( X ) is
A . ( 3 Omega )
B. ( 6 Omega )
( c .9 Omega )
D. ( 12 Omega )
12
345The ratio of the drifty velocity ( v_{d} ) and
r.m.s. velocity of electrons is
( mathbf{A} cdot 10^{-10} )
B . ( 10^{-5} )
( mathbf{c} cdot 10^{-3} )
D. ( 10^{-6} )
12
346Induced current is produced in a coil,
only when its ends are
A. not closed
B. closed
( c cdot operatorname{both} A & B )
D. None of the above
12
347Which is represented by the electric current?
A. Charge per unit volume
B. Charge per unit time
c. charge per unit area
D. Both A.and B
12
348Assertion
When a wire is stretched to two times
its length keeping the diameter same, its resistance becomes 4 times
Reason
Resistance is directly proportional to length of wire
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
349Brown, Red and Orange coloured bands
on a Carbon resistor are followed by silver band. The value of resistor is
( mathbf{A} cdot 320 Omega pm 5 % )
B . ( 12 k Omega pm 5 % )
c. ( 320 Omega pm 10 % )
D. ( 12 k Omega pm 10 % )
12
350When n number identical cell of emf ( mathrm{E} )
and internal resistance is connected in
series, the net internal resistance of the system will be
A ( cdot frac{n E r}{1+E} )
B ( cdot n^{2} r )
( c cdot n r )
D. ( n / r )
12
351In Wheatstone’s bridge the values of
resistors ( mathrm{P} ) and ( mathrm{Q} ) are respectively 3 and
x. If ( 4 Omega ) and ( 2 Omega ) are the values of
resistors ( mathrm{R} ) and ( mathrm{S} ) respectively, then ( times ) is
( A )
B. 1.5
( c cdot 2.5 )
( D cdot 2 )
12
352Electricians wear rubber gloves
because:
A. it is soft
B. it is water proof
c. it is an insulator
D. it is inexpensive
12
353A ( 5.0 mathrm{A} ) current is setup in an external
circuit by a ( 6.0 mathrm{V} ) storage battery for 6.0 min. The chemical energy of the battery is reduced by
В. ( 1.08 times 10^{-4} ) 」
c. ( 1.8 times 10^{4} ) j
D. ( 1.8 times 10^{-4} mathrm{J} )
12
354A wire of length ( L ) and 3 identical cells of negligible internal resistances are connected in series. Due to the current, the temperature of the wire is raised at ( triangle T ) in time ( t . N ) number of similar cells
is now connected in series with a wire of
the same material and cross-section
but of length ( 2 L ). The temperature of the
wire is raised by the same amount ( triangle boldsymbol{T} ) in the same time ( t ). The value of ( boldsymbol{N} ) is:
( A )
B. 6
( c cdot 8 )
( D )
12
355In figure the voltmeter and ammeter
shown are ideal. Then voltmeter and
A . ( 32.978 vee, 3 mathrm{A} )
B. 3 V, 0.236 A
c. ( 120 vee, 4.198 ) A
D. ( 120 vee, 3 mathrm{A} )
12
356Consider a conductor of variable cross
section in which current is flowing from
cross section 1 to 2 . Then
This question has multiple correct options
A. current passing through both the cross sections is the same
B. current through 1 is less than that through 2
c. drift velocity of electrons at 1 is less than that at 2 .
D. drift velocity is same at both the cross sections
12
357The voltages across the two resistors are given by ohm’s law as:
( mathbf{A} cdot V=I R )
в. ( V=I+R )
( c cdot V=frac{I}{R} )
D. ( V=I+frac{1}{R} )
12
358A letter ( A ) is constructed of a uniform
wire of resistance ( 1 Omega / c m . ) The sides of
the letter are ( 20 mathrm{cm} ) and the cross piece
in the middle is ( 10 mathrm{cm} ) long.The resistance between the ends of the legs will be:
A . ( 32.4 Omega )
B. ( 28.7 Omega )
c. ( 26.7 Omega )
D. ( 24.7 Omega )
12
359Relation between current in a conductor
and time is shown in Figure. If the
resistance of the conductor is ( R ), then
the total heat dissipated across
resistance ( boldsymbol{R} ) is :
A ( cdot frac{i_{0}^{2} R t_{0}}{2} )
B. ( frac{i_{0}^{2} R t_{0}}{4} )
c. ( frac{i_{0}^{2} R t_{0}}{3} )
D ( cdot i^{2}_{0} R t_{0} )
12
360Which of the following devices has a source of emf inside it?
A. Voltmeter
B. Ammeter
c. ohm-meter
D. Rectifier
12
361Two wires each of radius of cross
section ( r ) but of different materials are
connected together end to end (i.e., in series). If the densities of charge carriers in the two wires are in the ratio
( 2: 3, ) the drift velocity of electrons in the
two wires will be in the ratio of
A .2: 3
B. 3: 2
c. 4: 9
D. 9: 4
12
362The figure shows a source (a battery) with an emf ( E ) of ( 12 V ) with an internal
resistance ( r ) of ( 2 Omega ) and an external
resistance of ( 4 Omega ) is added to complete the circuit. What are the voltmeter and
12
363For a heater rated at ( 4.4 mathrm{kW} ; 220 mathrm{V} ) Calculate the current drawn by the heater.
A . 40 A
B. 20A
( c cdot 12.6 A )
D. ô
12
364Which of the following statements is
false?
A. Kirchhoff’s second law represents energy conservation.
B. Wheatstone bridge is the most sensitive when all the four resistances are of the same order of magnitude.
C. In a balanced Wheatstone bridge if the cell and the galvanometer are exchanged, the null point is disturbed.
D. A rheostat can be used as a potential divider.
12
365Assertion
IF a resistor is connected to a battery,
the current increases when the
temperature increases.
Reason
For resistors, resistance increases with
increase in temperature.
A . Assertion is incorrect and Reason is correct
B. Both Assertion and Reason are correct but Reason is the correct explanation for Assertion
c. Both Assertion and Reason are correct but Reason is not the correct explanation for assertion
D. Assertion is correct and Reason is incorrect
12
366In the figure shown below the maximum
possible unknown resistance ( (X) ) that can be measured by the post office box
( operatorname{are} X_{max } ) is given by ( R times 10^{5} Omega ) then ( mathrm{R} ) is
(given that in this experiment we can
take out only one plug from arm ( A B ) and
only one plug from arm BC but from arm AD we can take out many plugs)
12
367The battery of a trunk has an emf of ( 24 mathrm{V} ) If the internal resistance of the battery
is ( 0.8 Omega . ) What is the maximum current
that can be drawn from the battery?
A . 30 A
B. 32 A
c. 33 A
D. 34A
12
368The rate of flow of an electric charge is known as:
A. Electric potential
B. Electric conductance
c. Electric current
D. None of these
12
369A charge is moving across a junction,
then.
A. Momentum will be conserved
B. Momentum will not be conserved
C. At some places momentum will be conserved and at some other places momentum will not be conserved
D. None of these
12
370Why is the Wheatstone bridge better than the other methods of measuring resistances?
A. It does not involve Ohm’s law
B. It is based on Kirchoff’s law
c. It has four resistor arms
D. It is a null method
12
371In the fig. the potentiometer wire ( A B ) of
length ( L & ) resistance ( 9 r ) is joined to
the cell ( D ) of e.m.f. ( varepsilon ) and internal
resistance ( r . ) The cell ( C s ) e.m.f. is ( varepsilon / 2 )
and its internal resistance is ( 2 r . ) The
galvanometer ( G ) will show no deflection
then find length ( A J: )
12
372On comparing the emf’s ( E_{1} ) and
( boldsymbol{E}_{2}left(boldsymbol{E}_{1}>boldsymbol{E}_{2}right) ) of two cells by a
potentiometer, the balancing lengths
come out to be ( l_{1} ) and ( l_{2} ) respectively,
then
A ( cdot l_{1}l_{2} )
D. none of the above
12
373What potential difference is needed between the hands for a lethal shock
current?
( A cdot 100 V )
B. 10 ( v )
c. ( 120 v )
D. 150 V
12
374100 J of heat is produced each second in a ( 4 Omega ) resistor. Find the potential
difference across the resistor.
12
3754. In the experiment, the curve between Ax and AW is shown
as dotted line (1). If we use an another sx
wire of same material, but with double
length and double radius, which of the
curve is expected?
(a) 1
(b) 2
(c) 3
(d) 4
AW
12
376What is the expression for the electrical power spent in flow of current through a conductor in terms of
resistance and potential difference?
A. ( V^{2} / R )
в. ( V / R^{2} )
c. ( V R )
D ( cdot V^{2} R )
12
377In a closed circuit drawing current from cell, the emf of a cell is always
A. Less than potential difference
B. More than potential difference
c. Half of the potential difference
D. Double of the potential difference
12
378A wire has a nonuniform cross sectional
area as shown in the figure. A steady
current i flows through it. Which one of
the following statements is correct?
A. Drift speed of the electrons is constant
B. Drift speed of decreases on moving from A to B
C. Drift speed of increases on moving from A to B
D. Drift speed varies randomly
12
379Ine v-I grapn ror a conauctor at
temperature ( T_{1} ) and ( T_{2} ) are as shown in
the fig. The term ( left(T_{2}-T_{1}right) ) is
proportional to
A ( cdot frac{sin 2 theta}{sin ^{2} theta} )
B. ( frac{cot 2 theta}{sin ^{2} theta} )
c. ( frac{cos 2 theta}{sin 2 theta} )
D. ( frac{tan 2 theta}{sin ^{2} theta} )
12
380The tables show the resistance values
for three different resistors and the
currents through each resistor.
What is the ranking of the power
dissipated by each resistor, greatest
first?
( begin{array}{lc}text { Current 1 } & mathbf{2 I} \ text { Resistance 1 } & R \ text { Current 2 } & I \ text { Resistance 2 } & 2 R \ text { Current 3 } & I \ text { Resistance 3 } & 4 Rend{array} )
A ( .3,2, ) and 1 tie
( mathbf{B} cdot 3,2,1 )
( c )
1,2,3
D. 1 and 3 tie, 2
E . All tie
12
381A secondary cell after long use has an emf of ( 1.9 V ) and a large internal
resistance of ( 380 Omega ). What maximum
current can be drawn from the cell?
Could the cell drive the starting motor of
a car?
( mathbf{A} cdot 5 m A, ) yes
B. ( <5 m A ), Yes
( mathbf{c} .5 m A, ) No
( mathbf{D} cdot<5 m A, ) No
12
382The free electron gas theory explains conduction in
A. metals only
B. semiconductors only
c. insulators only
D. all of these
12
383Find the current through the ( 10 Omega )
resistor shown in figure:
( mathbf{A} cdot 0.5 A )
B. ( 1 A )
( c cdot 2 A )
D. ( 5 A )
12
384In the circuit shown in the figure, the
heat produced in the ( 5 Omega ) resistor due to
a current flowing in it, is 10 calories per
second. The heat produced in the ( 4 Omega )
resistor is?
A ( cdot 1 ) cal ( s^{-} )
B . 2 cal ( s^{-1} )
( c cdot 3 ) cal ( s^{-1} )
D. 4 cal ( s^{-} )
12
385Assertion
The temperature coefficient of resistance is always positive
Reason
On increasing the temperature the resistance of metals and alloys
increase
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
386Calculate the cost of using four 500 W air-conditioners for eight hours each
day for a 30 day month. The unit cost of electrical energy is Rs. 1.50 per ( mathrm{kWh} )
12
387If the figure shows a part of an electric
circuit, then the current ( I ) is
A . ( 1 A )
в. ( 3 A )
( c .2 A )
D. 4.4
12
388Calculate the force per unit length a
long sraight wire carring of 4.0 A due to a parallel wire carrying current of 6.0 a. This distance between the wire is 3.0
( mathrm{cm} )
12
the ( 2 Omega ) resistor in the circuit shown in
the figure.
12
390Which physical quantity cannot be determined with the help of
potentiometer?
( A )
B.
( c cdot L )
D. R
12
391In the following circuit diagram the
value of resistance ( X ) for the potential
difference between ( mathrm{B} ) and ( mathrm{D} ) is zero :
( A .4 ) ohm
B. 6 ohm
( c .8 ) ohm
D. 9 ohm
12
392The resistance of a metal increases
with the increase of temperature due to
A. Number of electrons
B. Velocity of electrons
c. Scattering of electrons with core ions
D. Thermal motion of core ions
12
393A potentiometer wire is ( 100 mathrm{cm} ) long and a constant potential difference is maintained across it. Two cells are
connected in series first to support one another and then in opposite direction. The balance points are obtained at 50 ( mathrm{cm} ) and ( 10 mathrm{cm} ) from the positive end of the wire in the two cases. The ratio of
emf’s is:
A . 5: 1
в. 5: 4
( c .3: 4 )
D. 3: 2
12
394The effective resistance between points
P and Q of the electrical circuit shown in
the figure is
A ( cdot frac{2 R r}{R+r} )
B. ( frac{8 R(R+r)}{3 R+r} )
( c cdot 2 r+4 R )
D. ( frac{5 R}{2}+2 )
12
395Heat produced in a wire of resistance ( boldsymbol{R} )
due to current flowing at constant potential difference is proportional to
A ( cdot frac{1}{R^{2}} )
в. ( frac{1}{R} )
( c . R )
D. ( R^{2} )
12
396How will the reading in the ammeter ( mathbf{A} )
of figure be affected if another identical
bulb ( Q ) is connected in parallel to ( P ) as
shown. The voltage in the mains is
maintained at a constant value
A. the reading will be reduced to one-half.
B. the reading will not be affected.
C. the reading will be double of the previous one
D. the reading will be increased fourfold.
12
397When the electric resistance are
connected in parallel, which one of the following quantities is not affected?
A. Potential difference
B. Resistance
c. Electric current
D. Capacity
12
398Figure given below shows uniformly
positively charged, thin rod of length ( L )
and four points ( A, B, C ) and ( D ) at the
same distance ( d ) from the rod, with
position as marked. If ( V_{A}, V_{B}, V_{C} ) and
( V_{D} ) are their respective potentials then.
A ( cdot V_{B}>V_{A}>V_{C}>V_{D} )
в. ( V_{B}>V_{A}>V_{C}=V_{D} )
( mathbf{c} cdot V_{A}=V_{B}>V_{C}=V_{D} )
D. ( V_{D}>V_{B}>V_{A}>V_{C} )
12
399A voltmeter of a very high resistance is joined in the circuit as shown in figure.
The voltage shown by this voltmeter will
be
( A cdot 5 V )
B. ( 6 V )
c. ( 2.5 V )
D. ( 3 V )
12
400In the figure, the potentiometer wire ( boldsymbol{A} boldsymbol{B} )
of length ( L ) and resistnace ( 9 r ) is joined
to the cell ( D ) of e.m.f and internal
resistance ( r . ) The cell ( C^{prime} ) s emf is ( varepsilon / 2 ) and
its internal resistance is ( 2 r )
The galvanometer ( G ) will show no
deflection when the length ( A J ) is
A. ( 4 L / 9 )
B. ( 5 L / 9 )
c. ( 7 L / 18 )
D. ( 11 L / 18 )
12
401An electrical appliance is rated
( mathbf{1 5 0 0} W, mathbf{2 5 0} V . ) This appliance is
connected to ( 250 V ) mains. Calculate
the current drawn.
A . ( 5 A )
в. ( 10 A )
( c cdot 6 A )
D. 2A\$
12
402A piece of copper and a piece of germanium are cooled from room temperature to ( 80 K . ) Then, which one of the following is correct?
A. Resistance of each will increase
B. Resistance of each will decrease
c. Resistance of copper will decrease while that of germanium will increase
D. Resistance of copper will increase while that of germanium will decrease
12
403In the arrangement shown in figure
when the switch ( S_{2} ) is open, the
galvanometer shows no deflection for
( l=L / 2 . ) When the switch ( S_{2} ) is closed,
the galvanometer shows no deflection
for ( l=5 L / 12 . ) The internal resistance
( (r) ) of ( 6 mathrm{V} ) cell, and the emf ( E ) of the other
battery are respectively
( A cdot 3 Omega, 8 V )
B. ( 2 Omega, 12 V )
c. ( 2 Omega, 24 V )
D. ( 3 Omega, 12 V )
12
404The figure shows three circuits I, II and
III which are connected to a ( 3 V ) battery.
If the powers dissipated by the
configurations ( boldsymbol{I}, boldsymbol{I} boldsymbol{I} ) and ( boldsymbol{I} boldsymbol{I} boldsymbol{I} ) are ( boldsymbol{P}_{1}, boldsymbol{P}_{2} )
and ( P_{3} ) respectively, then :
( mathbf{A} cdot P_{1}>P_{3}>P_{2} )
В ( cdot P_{2}>P_{1}>P_{3} )
( mathbf{c} cdot P_{1}>P_{2}>P_{3} )
( mathbf{D} cdot P_{3}>P_{2}>P_{1} )
12
405What is fractional change in the
resistance of a filament of ( boldsymbol{alpha}=mathbf{1 0} times )
( 10^{-4} /^{circ} mathrm{C}, ) when temperature changes
from ( 25^{circ} mathrm{C} ) to ( 40^{circ} mathrm{C} ? )
12
406The resistance of a metallic conductor
increases with temperature due to:
A. change in carrier density
B. change in dimension of the conductor
C. increase in the number of collisions among the carriers
D. increase in the rate of collisions between the carriers and the vibrating atoms of the conductor.
12
407Two cells of emf ( 1.5 v ) and ( 2.0 v ) have
internal resistances ( 0.2 Omega ) and ( 0.3 Omega )
respectively are connected in parallel. Calculate the emf and internal
resistance of the equivalent cell?
12
408A length of ( 150 mathrm{cm} ) of a potentiometer wire is required to balance the emf of a cell. When a ( 5 Omega ) resistor is connected
across the terminals of the cell, the
length required for balance is ( 125 mathrm{cm} )
The internal resistance of the cell is
A . 1 ohm
B. 1.1 ohm
c. 1.2 ohm
D. 1.3 ohm
12
409For a given voltage ( V ), if resistance is
changed from ( R ) to ( left(frac{R}{n}right), ) power
consumed changes from ( P ) to:
( A cdot n P )
B. ( frac{p}{n} )
( c cdot n^{2} p )
D. ( frac{P}{n^{2}} )
12
410The resistance of a heating element is
( 99 Omega ) at room temperature. What is the temperature of the element if the
resistance is found to be ( 116 Omega ? )
(Temperature coefficient of the material
of the resistor is ( 1.7 times 10^{-4} o C^{-1} ) ).
A ( cdot 9999^{circ} mathrm{C} )
B . ( 1005.3^{circ} mathrm{C} )
( mathbf{c} cdot 1020.2^{circ} mathrm{C} )
D. ( 1037.1^{circ} mathrm{C} )
12
411A student carries out an experiment
and plots the ( V ) -I graph of three samples
of nichrome wire
with resistances ( mathrm{R} 1, ) R2 and ( mathrm{R} 3 )
respectively (Figure.12.5). Which of the
following is true?
( mathbf{A} cdot R_{1}=R_{2}=R_{3} )
B ( cdot R_{1}>R_{2}>R_{3} )
( mathbf{c} cdot R_{3}>R_{2}>R_{1} )
( mathbf{D} cdot R_{2}>R_{3}>R_{1} )
12
412Match the Column I with Column II.
Column I
(Physical
quantity) Column II
(Dimensional
formula) (Dimensio
formula)
(A) Premittivity
of free
space
( (p) )
( left[M^{0} L^{0} T^{-1}right] )
(В) ( left[M L^{3} T^{-3} A^{-2}right] )
(C) ( begin{array}{ll}text { Radiant flux } & text { (q) } \ text { Resistivity } & text { (r) } \ text { Hubble } & text { (s) } \ text { constant } & text { (s) }end{array} ) ( left[mathrm{M} mathrm{L}^{2} mathrm{T}^{-3}right] ) A
(D) (s) ( quadleft[M^{-1} L^{-3} T^{4} A^{2}right] )
( A cdot A-p, B-q, C-r, D-s )
B. ( A-q, B-p, C-s, D-r )
C. ( A-s, B-r, C-q, D-p )
( D cdot A-r, B-s, C-q, D-p )
12
413When current ( i ) is flowing through a conductor, the drift velocity is ( v ). If the value of current through the conductor and its area of cross-section is doubled,
then new drift velocity will be
A . ( 4 v )
в. ( frac{v}{2} )
c. ( frac{v}{4} )
D. ( v )
12
414When a battery connected across a resistor of ( 15 Omega, ) voltage across the resistor in ( 12 V . ) When the same battery
is connected across a resistor of ( 10 Omega )
voltage across it is ( 11 mathrm{V} ). The internal
resistance of the battery (in ohm) is
A. ( frac{10}{7} )
в. ( frac{20}{7} )
( c cdot frac{2}{7} )
D. ( frac{30}{7} )
12
415A ( 10 mathrm{V} ) battery with internal resistance 1
( Omega ) and a ( 15 V ) battery with internal
resistance ( 0.6 Omega ) are connected in
parallel to a voltmeter. The reading in
the voltmeter will be close to
( A, 11.9 mathrm{V} )
в. 13.1
c. ( 24.5 mathrm{v} )
D. ( 12.5 mathrm{v} )
12
416A resistance of ( 2 Omega ) is connected across one gap of a metre bridge (the length of the wire is ( 100 mathrm{cm} ) ) and an unknown
resistance greater than ( 2 Omega ) is connected across the other gap. When these resistances are interchanged, the balance point shifts by ( 20 mathrm{cm} ) Neglecting any corrections, the unknown resistance is:
A . ( 4 Omega )
в. 3 ( Omega )
( c cdot 5 Omega )
D. ( 6 Omega )
12
417Which color band in the color coding of a resistor has the multiplier ( 10^{-1} ) ?
A. Silver
B. Gold
c. Yellow
D. orange
12
418Fill in the blank:
To increase the effective resistance in a
circuit the resistors are connected in
12
419Match list – I with List – II
List –

List – II
a) Thermistor
e) High positive ( boldsymbol{alpha} )
b) Carbon
f) ( alpha ) almost zero
c) Nichrome
g) either positive or negative ( boldsymbol{alpha} )
d) Constantan
h) Negative ( alpha ) manganin
A. a-g, b-h, c-e, d-f
B. a-h, b-g, c-e, d-f
c. a-e, b-f, c-g, d-h
D. a-e, b-g, c-h, d-f

12
420If a cell of constant E.M.F. produces the same amount of the heat during the same time in two independent resistors
( boldsymbol{R}_{1} ) and ( boldsymbol{R}_{2}, ) when they are separately connected across the terminals of the
cell, one after the another, the internal resistance of the cell is ( sqrt{x R_{1} R_{2}} ). Find ( x )
12
421In the circuit shown, the galvanometer shows zero current.The value of
resistance R is :
( 4.1 Omega )
В. ( 10 Omega )
( c cdot 4 Omega )
D. ( 9 Omega )
12
422Below is a chart describing the
parameters of 5 metal wires:
begin{tabular}{lll}
Wire & Length ( (boldsymbol{m}) ) & Diameter ( (boldsymbol{m m}) ) \
1 & 1 & 0.5 \
2 & 1 & 1 \
4 & 2 & 0.5 \
5 & 2 & 1 \
hline 6 & 2 & 2 \
hline
end{tabular} Assuming all of the wires are made
from the same material, rank these
wires from highest to lowest resistance.
A. 4,5,6,1,3,2
B. 3,2,1,6,5,4
C. 4,1,5,2,6,3
D. 1,4,2,5,3,6
E. 4,5,6,1,2,3
12
423A material B’ has twice the specific
resistance of ( mathbf{A}^{prime} . ) A circular wire made of
B’ has twice the diameter of a wire
made of ( mathbf{A}^{prime} . ) Then for the two wires to
have the same resistance, the ratio
( boldsymbol{P}_{mathrm{A}} / boldsymbol{P}_{mathrm{B}} ) of their respective lengths must
be
( A cdot 2 )
B. 1
( c cdot frac{1}{2} )
D.
12
424In Figure circuit section, ( A B ) absorbs
energy at a rate of 50W when a current
( =1.0 mathrm{A} ) passes through it in the indicated direction. What is the
potential difference between ( A ) and ( B ) ?
A ( .10 V )
в. ( 50 V )
( c cdot 20 V )
D. 30V
12
425If doubling the voltage across a resistor doubles the current through the resistor
then
A. the resistor value decreased.
B. the resistor value increased
c. the resistor value did not change.
D. it is impossible to determine the change in the resisto value
12
426The resistance of the given carbon
resistor is ( left(2.4 times 10^{6} pmright) 5 % Omega . ) What is
the sequence of colours on the strips provided on resistor?
12
427Give reasons for the following. Stationary coil and stationary magnet can not produce induced electric
current
12
428The drift velocity of an electron is
doubled if the applied electric field across the conductor is
A. three times
B. doubled
c. half
D. four times
12
429Two electric bulbs have ratings respectively of ( 25 W, 220 V ) and ( 100 W, 220 V ). If the bulbs are connected
in series with a supply of ( 440 V, ) which bulb will fuse?
( mathbf{A} cdot 25 W ) bulb
B. ( 100 W ) bulb
c. Both of these
D. None of these
12
430Masses of three wires of the same
metal are in the ratio 1: 2: 3 and their
lengths in the ratio ( 3: 2: 1 . ) Electrical
resistances of these wires will be in the
ratio
A. 1: 2: 3
B. 3: 2: 1
c. 1: 6: 27
D. 27: 6: 1
12
431If the temperature of a conductor is increased, its resistance will
A. not increase
B. increase.
c. decrease.
D. change according to the whether
12
432At what moment when the
potentiometer is balanced
A. Current flows only in the primary circuit.
B. Current flows only in the secondary circuit
c. current flows in both primary and secondary circuits.
D. current doesnot flow in any circuit
12
433In comparing e.m.f.s of 2 cells with the
help of potentiometer, at the balance point, the current flowing through the wire is taken from:
A. 1 ) Any one of these cells
B. 2) both of these cells
c. 3 ) Battery in the main circuit
D. 4 ) From an unknown source
12
434For a heater rated at ( 4 k W ; 220 V )
Calculate the resistance of the heater
element.
A . ( 20 Omega )
B . ( 21.6 Omega )
c. ( 200 Omega )
D. ( 12.2 Omega )
12
435Each resistor shown is 9 ohms.
When hooked to a 6 -volt battery, which combination would produce 2 watts of
power?
( A )
B.
( c )
D.
12
436The number of electrons in the
outermost orbit of carbon atom is
( A cdot 3 )
B. 4
( c cdot 6 )
( D )
12
437A wire had a resistance of ( 12 Omega ). It is bent
in the form ofa circle.The effective resistance between two points on any diameter is
A . ( 3 Omega )
B. ( 6 Omega )
( c .12 Omega )
D. ( 24 Omega )
12
438Assertion
In a meter bridge experiment null point for an unknown resistance is put inside
an enclosure maintained at a higher temperature. The null point can be obtained at the same point as before by decreasing the value of the standard resistance.
Reason
Resistance of metal increases with
increase in 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
439Three equal resistors connected in
series across a source of e.m.f.
dissipate 10 watts of power. What will be the power dissipated in watts if the same resistors are connected in paralle
across the same source of e.m.f.?
A. ( 10 W )
в. ( 30 W )
c. ( 90 W )
D. ( frac{10}{3} W )
12
440is a property that resists the flow of electrons in a conductor.
A. Capacitance
B. Inductance
c. Resistance
D. None of above
12
441For the circuit shown in Figure, the
equivalent resistance between ( boldsymbol{A} ) and ( boldsymbol{C} )
is
( A cdot frac{12}{11} )
B. ( frac{13}{11} )
( c cdot frac{14}{11} r )
( D cdot frac{15}{11} )
12
442A source of constant potential
difference is connected across a
conductor having irregular cross-
section as shown in figure. Then :-
A. Electric field intensity at ( P ) is greater than at ( Q ).
B. Rate of electric current crossing per unit area of cross section at ( P ) is less than that at ( Q )
C. The rate of generation of heat per unit length at ( P ) is greater than that at ( Q ).
D. Mean kinetic energy of free electron at ( P ) is greater than that at ( Q )
12
443toppr
of potential difference across it is
3
( c )
D
12
444When a potential difference ( boldsymbol{V} ) is
applied across a conductor at a temperature ( boldsymbol{T}, ) the drift velocity of electrons is proportional to
( mathbf{A} cdot sqrt{V} )
в. ( V )
c. ( sqrt{T} )
D. ( T )
12
445The potentiometer wire of length has
( 100 mathrm{cm} ) has a resistance of ( 10 Omega ).It is
connected in series with a resistance of
( 5 Omega ) and an acceleration of emf ( 3 V )
having magnitude resistance. A source A source of ( 1.2 mathrm{V} ) is balanced against
ength I’ Of the potential wire. Find the
value of L.
12
446In the circuit shown in figure. Current
through ( R_{2} ) is zero if ( R_{4}=2 Omega ) and
( boldsymbol{R}_{3}=mathbf{4} boldsymbol{Omega} )
In this case:
A . current through ( R_{3} ) is ( 2 A )
B. current through ( R_{4} ) is 3 A
( c . ) both (1) and (2) are correct
D. both (1) and (2) are wrong
12
447The current ( I ) and voltage ( V ) graphs for a
given metallic wire at two different
temperatures ( T_{1} ) and ( T_{2} ) are shown in
the figure. It is concluded that :
A ( cdot T_{1}>T_{2} )
В. ( T_{1}<T_{2} )
( mathbf{c} cdot T_{1}=T_{2} )
D. ( T_{1}=2 T_{2} )
12
448What conclusion can you draw from the following observations on a resistor
( begin{array}{llll}begin{array}{l}text { Current } \ text { A }end{array} & begin{array}{l}text { Voltage } \ text { V }end{array} & begin{array}{l}text { Current } \ text { A }end{array} & begin{array}{l}text { Voltage } \ text { v }end{array} \ begin{array}{l}text { 0.2 } \ text { 0.4 }end{array} & begin{array}{l}text { 3.94 } \ text { 7.87 }end{array} & begin{array}{l}text { 3.0 } \ text { 4.0 }end{array} & begin{array}{l}text { 59.2 } \ text { 78.8 }end{array} \ begin{array}{l}text { 0.6 } \ text { 0.8 }end{array} & begin{array}{l}text { 11.8 } \ text { 15.7 }end{array} & begin{array}{l}text { 5.0 } \ text { 1.0 }end{array} & begin{array}{l}text { 6.0 } \ text { 19.7 }end{array} & begin{array}{l}text { 98.6 } \ text { 7.0 }end{array} & begin{array}{l}text { 118.5 } \ text { 138.2 }end{array} \ begin{array}{ll}text { 2.0 } & text { 39.4 } & text { 8.0 } & text { 158.0 }end{array}end{array} )
12
449If the color code of the carbon
resistance is Red, Orange yellow, Gold. Find the value of resistance.
12
450The value of the resistance ( R ) in figure
is adjusted such that power dissipated
in the ( 2 Omega ) resistor is maximum. Under
this condition
This question has multiple correct options
A ( . R=0 )
в. ( R=8 Omega )
c. power dissipated in the ( 2 Omega ) resistor is ( 72 ~ W )
D. power dissipated in the ( 2 Omega ) resistor is ( 8 W )
12
451The masses of three copper wires are in the ratio 1: 2: 3 and their lengths are
in the ratio ( 3: 2: 1 . ) The ratio of their
resistance is:
A. 27: 6: 1
B. 9: 3: 1
( mathrm{c} cdot 6: 3: 2 )
D. 1: 2: 3
12
452The length of a potentiometer wire is 10m. The distance between the null
points on its wire corresponding to two cells comes out to be ( 60 mathrm{cm} ). If the difference of emf’s of the cells is 0.4 volt
then the potential gradient on potentiometer wire will be
( A cdot 0.67 mathrm{V} / mathrm{m} )
B. ( 0.5 vee / ) m
c. ( 2.5 mathrm{V} / mathrm{m} )
D. ov ( / mathrm{m} )
12
453When the current in a wire is ( 1 A ), the
drift velocity is ( 1.2 times 10^{-4} mathrm{ms}^{-1} . ) The
drift velocity when current becomes 5 A
is
A ( cdot 1.2 times 10^{-4} mathrm{ms}^{-1} )
В. ( 3.6 times 10^{-4} mathrm{ms}^{-1} )
( mathbf{c} cdot 6 times 10^{-4} m s^{-1} )
D. ( 4.8 times 10^{-4} mathrm{ms}^{-1} )
12
454As the temperature of a conductor
increases, its resistivity and
conductivity change. The ratio of resistivity to conductivity
A. increases
B. decreases
c. remains constant
D. may increase or decrease depending on the actual temperature
12
455An ionization chamber with parallel conducting plates as anode and
cathode, has ( 5 times 10^{7} ) electrons and the
same number of singly charged positive ions per ( c m^{3} . ) The electrons are moving
towards the anode with velocity ( 0.4 mathrm{m} / mathrm{s} ) The current density from anode to
cathode is ( 4 mu A / m^{2} . ) The velocity of positive ions moving towards cathode is
A. ( 0.4 m s^{-1} )
B. zero
c. ( 1.6 m s^{-1} )
D. ( 0.1 m s^{-1} )
12
456There are two wires, ( A ) and ( B ), made of same material. Both the wires have the
same length. It is observed that the resistance of wire ( A ) is four times
the resistance of wire ( mathrm{B} ), then find the
ratio of their cross sectional areas.
A . 4: 1
B. 1: 4
c. 1: 2
D. 2: 1
12
457Three resistance ( P, Q, R ) each of ( 2 Omega ) and
an unknown resistance S form the four
arms of a Wheatstone’s bridge circuit. When a resistance of ( 6 Omega ) is connected
in parallel to ( mathrm{S} ) the bridge gets balanced What is the value of S?
A . ( 2 Omega )
B. 3Omega
( c cdot 6 Omega )
D. 1Omega
12
458Match the following:
Column II gives the order of resistivity for materials in column I
12
459Which color band in the resistor is
having highest tolerance?
A . Violet
B. Green
c. Blue
D. None of the above
12
460The number of 160 ohms resistors to
be connected in parallel to produce 5 A current on a ( 100 mathrm{V} ) line is:
( A cdot 2 )
B. 4
( c cdot 8 )
D. 10
12
461In the circuit shown in the figure, the
heat produced in the ( 5 Omega ) resistor due to
the current flowing through it is
( mathbf{1 0} ) cal ( s^{-1} )
The heat generated in the ( 4 Omega ) resistor is
A ( cdot 1 ) cal ( s^{-1} )
B. 2 cal ( s^{-1} )
c. 3 cal ( s^{-1} )
D. 4 cal ( s^{-} )
12
462In a torch there are two cells each of
1.45 volt and ( 0.15 Omega . ) Each cell gives a
current to filament of a lamp of ( 1.5 Omega ) then the value of current in ampere is :-
A. 16.11
B. 1.611
c. 0.1611
D. 2.6
12
463The resistance of a conductor is:
A. Inversely proportional to the length
B. Directly proportional to the square of the radius
C. Inversely proportional to the square of the radius
D. Directly proportional to the square root of the length
12
464A current passes through an ohmic
conductor of nonuniform cross section.
Which is the following quantities are independent of the cross-section? This question has multiple correct options
A. The charge crossing in a given time interval
B. Drift speed
c. Current density
D. Free-electron density
12
465Rate at which electric work is done is
called as ?
A. electric power
B. electric energy
c. electric force
D. voltage.
12
466Assertion
A steady current is flowing in a conductor hence there is an electric
field within the conductor and
Reason
In case of steady current, there can be
no accumulation of charges, so no
electric field can be established.
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
467Drift velocity ( v_{a} ) varies with the intensity
of elastic filed as per the relation:
A ( cdot v_{a} ) is directly proportionate to
B. ( v_{a} ) is inversely proportionate to E
( mathbf{c} cdot v_{a} ) is constant
D. ( v_{a} ) is directly proportional to ( E^{2} )
12
468In the circuit shown in figure, ammeter
and voltmeter are ideal. If ( boldsymbol{E}=mathbf{4} boldsymbol{V}, boldsymbol{R}= )
( 9 Omega ) and ( r=1 Omega, ) then readings of
ammeter and voltmeter are
This question has multiple correct options
A ( cdot A_{m}=1 A )
B . ( A_{m}=2 A )
c. ( V_{m}=3 V )
D. ( V_{m}=4 V )
12
469Two ( 2 Omega ) resistances are connected in
parallel in circuit ( X ) and in series in
circuit Y. The batteries in the two
circuits are identical and have zero
internal resistance. Assume that the
energy transferred to resistor A in
circuit ( X ) within a certain time is ( W ). The
energy transferred to resistor ( mathrm{B} ) in
circuit ( Y ) in the same time will be:
A ( cdot frac{1}{4} w )
B. ( frac{1}{2} w )
c. ( 2 w )
D. ( 4 mathrm{w} )
12
470Which graph represents the total heat
developed from time ( t=0 ) by a resistor
( (mathbf{A}) )
( (mathbf{D}) )
12
471toppr
across the resistor wire AB. A
standard cell which maintains a
constant emf of ( 1.02 mathrm{V} ) (for very
moderate currents up to a few mA)
gives a balance point at ( 67.3 mathrm{cm} ) length of the wire. To ensure very low currents drawn from the standard cell, a
very high resistance of 600 ( mathrm{k} Omega ) is put in series with it, which is shorted close to
the balance point. The standard cell is
then replaced by a cell of unknown emf
and the balance point found similarly, turns out to be at ( 82.3 mathrm{cm} ) length of the
wire.(a) What is the value ( varepsilon ?(b) ) What
purpose does the high resistance of 600
k ( Omega ) have?(c) Is the balance point
affected by this high resistance?
(d) Is
the balance point affected by the internal resistance of the driver cell?
(e) Would the method work in the above
situation if the driver cell of the
potentiometer had an emf of ( 1.0 mathrm{V} ) instead of 2.0 V?(f) Would the circuit
work well for determining an extremely small emf, say of the order of a few mV (such as the typical emf of a thermocouple)? If not, how will you modify the
circuit?
12
472In the method using the transformers, assume that the ratio of the number of
turns in the primary to that in the secondary in the step-up transformers
is ( 1: 10 . ) If the power to the consumers
has to be supplied at ( 200 V, ) the ratio of the number of turns in primary to that in the secondary in the step-down transformer is
B. 150: 1
c. 100: 1
D. 50: 1
12
473Figure shows a meter bridge (which is nothing but a practical Wheatstone bridge), consisting of two resistors ( X )
and Y together in parallel with a meter long constantan wire of uniform cross
section. Which the help of a movable
contact ( mathrm{D} ), one can change the ratio of resistance of the two segments of the
wire until a sensitive galvanometer ( G )
connected across B and D shows no
deflection. The null point is found to be a distance of ( 33.7 mathrm{cm} . ) The resistor Y is
shunted by a resistance of ( 12 omega, ) and the null point is found to shift by a distance of ( 18.2 mathrm{cm} . ) Determine the approximate resistance of ( X ) and ( Y ) in ohm.
12
474Write Kirchhoff’s first rule (law of
junction). Drawing a circuit diagram of Wheatstone bridge, derive condition for zero deflection in the bridge.
12
475The sides of rectangle block are 23 and
( 4 mathrm{cm} ) The ratio of the maximum to
minimum resistance between its
parallel force is.
12
476Infinite charges are lying at ( boldsymbol{x}= )
( 1,2,4,8 dots ) meter on ( X ) -axis and the
value of each charge is ( Q . ) The value of
intensity of electric field at point ( boldsymbol{x}=mathbf{0} ) due to these charges will be respectively
( mathbf{A} cdot 12 times 10^{8} Q N / C )
в. zero
c. ( 69 times 10^{9} Q N / C )
D. ( 4 times 10^{9} Q N / C )
12
477In Fig. voltmeter is not ideal. If the
voltmeter is removed from ( boldsymbol{R}_{1} ) and then
put across ( R_{2}, ) what will be the effect on
current I? Given ( boldsymbol{R}_{1}>boldsymbol{R}_{2} )
This question has multiple correct options
A . decreases
B. remains same
( c ). increases
D. it would have been same if voltmeters were idea
12
478The effective equivalent resistance
between A and B in the figure, is?
A ( cdot frac{3}{2} )
B. ( frac{2}{3} ) R
c. ( frac{2}{5} ) R
D. 2 R
12
479Find the value of ( R ) so that no deflection
is noticed in the galvanometer when the
switch ( S ) is closed or open
A . ( 4 Omega )
B. ( 8 Omega )
( c cdot 6 Omega )
D. None of these
12
480In a metre bridge, the balancing point obtained at ( 40 mathrm{cm} . ) If a resistance equa
that in the left gap is shunted across it
the new balancing point.
( A cdot 20 mathrm{cm} )
B. 25 cm
c. ( 30 mathrm{cm} )
D. 15 ( mathrm{cm} )
12
481The diameter of a copper wire is ( 2 mathrm{mm} ) a steady current of 6.25 A is generated by ( 8.5 times 10^{28} / m^{3} ) electrons flowing
through it. Calculate drift velocity of conduction electrons.
12
482For a given cell, its terminal voltage depends on and
A. external resistance, internal resistance
B. internal resistance only
c. external resistance only
D. none of these
12
483Mention two limitations of Ohm’s law.12
484What is the ratio of heat generation in ( mathrm{R} )
and ( 2 R ) in same time in.
12
485Which of the following is true for carbon resistors?
A. Resistance value does not get changed by change in temperature
B. Current carrying capacity and hence power wattage are limited to about 50 watts
c. It has low-temperature coefficient value.
D. stability and reliability are very good.
12
486At ( 100^{circ} mathrm{C}, ) resistance of a conducting
coil is ( 4.2 Omega . ) If the temperature
coefficient of resistance is ( 0.004^{circ} mathrm{C} )
what will be the resistance of ( 0^{circ} mathrm{C} ) ? (in
ohm
( A cdot 3 )
B. 5
( c cdot 4 )
D. 3.5
12
487An electric motor operating on ( 50 V ) D.C.
supply draws a current of ( 10 A ). If the efficiency of the motor is ( 40 % ), then the resistance of the winding of the motor is:
A. ( 1.5 Omega )
B. 3Omega
c. ( 4.5 Omega )
D. ( 6 Omega )
12
488Which of the following statements
is/are incorrect for a meter bridge,
which is used to compare two
resistances?
A. If its wire is replaced by another wire having same length, made of same material but having twice the cross sectional area, the accuracy increases.
B. If its wire is replaced by another wire of different material, having same cross sectional area but of twice the length, accuracy increases.
C. If its wire is replaced by another wire of same material, having half the cross sectional radius and half the length, accuracy decreases but sensitivity increases
D. Metre bridge works on the principle of Wheat-stone bridge
12
489Two cells of emf ( E_{1} ) and ( E_{2}left(E_{1},>E_{2}right) )
are connected as shown in figure. When
a potentiometer is connected between ( mathbf{A} ) and ( mathrm{B} ), the balancing length of the potentiometer wire is ( 300 mathrm{cm} ). When the
same potentiometer is connected between ( A ) and ( C, ) the balancing length
is ( 100 mathrm{cm} . ) The ratio of ( E_{1} ) and ( E_{2} ) is
( A cdot 3: 2 )
B. 4: 3
( c cdot 5: 4 )
D. 2: 1
12
490A ( 60 mathrm{HP} ) car is moving with a uniform velocity of ( 54 mathrm{km} / mathrm{hr} ). Find the forward force exerted by its engine.12
491A counter consists of a cylindrical cathode of radius ( 1 c m ) and an anode
wire of radius ( 0.01 c m ) which is placed along the axis of the cathode. A voltage of ( 2.3 k V ) is applied between the
cathode and anode. The electric field on
the anode surface must be:
A ( cdot 2.3 times 10^{5} V m^{-1} )
B. ( 5 times 10^{6} V m^{-1} )
( mathbf{c} cdot 4.6 times 10^{5} mathrm{Vm}^{-1} )
D. ( 2.5 times 10^{6} mathrm{Vm}^{-1} )
12
492A square aluminium rod is ( 1 mathrm{m} ) long and ( 5 mathrm{mm} ) on edge. What must be the radius of another aluminium rod whose length
is ( 1 mathrm{m} ) and which has the same
resistance as the previous rod?
A. ( 5.0 mathrm{mm} )
B. 4.2 mm
( c .2 .8 mathrm{mm} )
D. ( 1.4 mathrm{mm} )
12
493In the meter bridge shown, the
resistance ( X ) has a negative
temperature coefficient of resistance.
Neglecting the variation in other
resistors, when current is passed for
some time, in the circuit balance point
should shift towards:
( A cdot A )
в. ( B )
( c . ) First ( A ) then ( B )
D. It will remain at
12
494Three copper wires of lengths and cross sectional areas are ( (l, A)left(2 l, frac{A}{2}right) ) and ( left(frac{l}{2}, 2 Aright) . ) Resistance is minimum in
A ( cdot ) wire of cross-sectional area ( frac{A}{2} )
B. wire of cross-sectional area ( A )
c. wire of cross-sectional area ( 2 A )
D. same in all the three cases
12
495A metal wire of resistance ( 3 Omega ) is
elongated to make a uniform wire of
double its previous length. This new wire is now bent and the ends joined to make a circle. If two points on this circle
make an angle ( 60^{circ} ) at the centre, the equivalent resistance between these
two points will be?
A ( cdot frac{12}{5} Omega )
в. ( frac{5}{3} Omega )
c. ( frac{5}{2} Omega )
D. ( frac{7}{2} Omega )
12
496In a potentiometer experiment, it is found that no current passes through the galvanometer when the terminals of
the cell are connected across ( 52 mathrm{cm} ) of
the potentiometer wire. If the cell is shunted by a resistance of ( 5 Omega, ) a balance is found when the cell is
connected across ( 40 mathrm{cm} ) of the wire. Find
the internal resistance of the cell.
A . ( 1.5 Omega )
B . 2Omega
( c .2 .5 Omega )
D. 12
12
497Which physical quantity is measured in ( k W )
A. electric energy
B. voltage
c. charge
D. electric power
12
498In the circuit shown in the fig the heat
produced in resistance ( R_{1} ) can be
measured by
A. connecting both voltmeter and an ammeter in parallel to ( R_{1} )
B. connecting ammeter in series with ( R_{1} ) and voltmeter in parallel to both ( R_{1} ) and ( R_{2} )
C. connecting ammeter in parallel to ( R_{1} ) and voltmeter in
series with ( R_{1} )
D. connecting voltmeter in parallel to ( R_{1} ) and ammeter in
series with ( R_{1} )
12
499In case of the circuit arrangement shown below, the equivalent resistance
between ( A ) and ( B ) is:
A. ( 10 Omega )
3. ( 2.5 Omega )
( c cdot frac{50}{3} s )
Done of the above
12
500In the figure shown below, the
maximum possible unknown resistance ( (X), ) that can be measured by
the post office box are ( X_{max } ) is fiven by
( R times 10^{5} Omega, ) then ( R ) is (given that in this
experiment, we can take out only one plug from arm ( A B ) and only one plug from arm BC, but from arm AD we can
take out many plugs):
( A )
B.
( c )
E. none of thes
12
501In a meter bridge experiment, the null point is obtained at ( 20 mathrm{cm} ) from one end of the wire when resistance ( boldsymbol{X} ) is
balanced against another resistance ( Y )
If ( X<Y ), then where will the new position of the null point be from the
same end, if one decides to balance a
resistance of ( 4 X ) against ( Y ? )
( mathbf{A} cdot 40 mathrm{cm} )
в. ( 80 mathrm{cm} )
( c .50 mathrm{cm} )
D. ( 70 mathrm{cm} )
12
502Copper wire of length ( 3 m ) and the area
of cross section ( 1.7 times 10^{-6} m^{2} ) has a
resistance of ( 3 times 10^{-2} m^{2} ) ohms.
Calculate the resistivity of copper?
12
503The balancing point in a meter bridge is ( 44 mathrm{cm} . ) If the resistances in the
are gaps are inchanged the new balance point is
A. ( 44 mathrm{cm} )
B. 56 ( mathrm{cm} )
c. ( 50 mathrm{cm} )
D. 22 ( mathrm{cm} )
12
504A bulbs is connected to a battery of p.d. ( 4 mathrm{V} ) and internal resistance ( 2.5 Omega . A )
stedy current of ( 0.5 mathrm{A} )
(i) the total energy supplied by the battery in 10 minutes,
(ii) the resistance of the bulb,and
(iii) the energy displated in the bulb in
10 minutes
12
505Can we measure a resistance of the
order of ( 0.160 Omega ) using a Wheatstone’s
12
506The current in the given circuit is
A. 0.3 amp
B. 0.4 amp
( mathbf{c} cdot 0.1 mathrm{amp} )
D. 0.2 amp
12
507If a wire of resistance ( R ) is stretched to
double of its length keeping the diameter same, then new resistance
will be:
A. ( R / 2 )
в. ( 2 R )
( c .4 R )
D. ( 16 R )
12
508Two rods ( A ) and ( B ) made up of same metal have same length. The ratio of their resistances is ( 1: 2 . ) If these rods are
immeresed in water then loss in weight will be :-
( A . ) more in ( A )
B. more in B
c. same is A and B
D. in the ratio 1: 2
12
509A cylindrical bar magnet is kept along the axis of a circular coil. If the magnet is rotated about its axis, then –
A. a current will be induced in the coil
B. no current will be induced in the coil
c. only emf will be induced in the coil
D. an emf and current both will be induced in the coil
12
510The current ( I_{1}(text { in } A) ) flowing through ( 1 Omega )
resistor in the above circuit is :
A . 0.25
B. 0.2
( c .0 .5 )
D. 0.4
12
511The ratio of the concentration of electrons to that of holes in a semiconductor is ( frac{7}{4}, ) then what is the ratio of their drift velocities:
A ( cdot frac{5}{8} )
B. ( frac{4}{5} )
( c cdot frac{5}{4} )
( D cdot frac{4}{7} )
12
512Three equal resistors connected across
a source of e.m.f. together dissipate 10 watt of power. What will be the power dissipated in watts if the same resistors are connected in parallel
across the same source of e.m.f?
A . 10
в. ( frac{10}{3} )
( c . ) 30
D. 90
12
513The potential differnce ( left(boldsymbol{V}_{boldsymbol{A}}-boldsymbol{V}_{boldsymbol{B}}right) )
between the points ( A ) and ( B ) in the given
figure is
A ( .9 V )
B. ( 6 V )
( c .3 V )
D. ( 4 V )
12
514State whether given statement is True or False
Glass is a good insulator.
A. True
B. False
12
515A current of ( 300 mathrm{mA} ) is made to flow
through a ( 6 k Omega ) resistor. What is the potential difference across the resistor?
A . ( 1800 v )
B. 50v
c. ( 0.02 v )
D. 500v
12
516Copper and Carbon wires are connected in series and the combined resistor is
kept at ( 0^{circ} mathrm{C} ). Assuming the combined resistance does not vary with
temperature, the ratio of the resistances of Carbon and Copper wires
at ( 0^{circ} C ) is:
(Temperature coefficients of resistivity of Copper and Carbon respectively are ( left.4 times 10^{-3} /^{circ} C text { and }-0.5 times 10^{-3} /^{circ} Cright) )
( A )
в. 6
( c cdot 2 )
( D )
12
517A straight conductor of uniform cross-
section carries a current, ( I ). If ( ^{prime} s^{prime} ) is the
specific charge of an electron, the momentum of all the free electrons per unit length of the conductor, due to their drift velocity only, is
A . Is
в. ( sqrt{frac{I}{s}} )
c. ( frac{1}{s} )
( left(frac{I}{s}right)^{2} )
12
518The resistance of ( 2 Omega ) is connected
across one gap of a meter-bridge (length of the wire is ( 100 mathrm{cm} ) ) and an unknown resistance greater than ( 2 Omega ) is connected across the other gap. When the resistance are interchanged, the balance point shifts by 20cm. Neglecting any corrections, the unknown resistance is: ( (text { in } Omega) )
12
519Which of the following statement is
correct?
A. Liquids obey partially the Ohm’s law
B. Liquids fully obeys the Ohm’s law
C. Liquid do not obeys the Ohm’s law
D. None of the above
12
520A charge q of mass m starting from rest is allowed to move between two points having a potential difference of V volts. What is the final velocity of the charge?12
521In Wheatstone’s bridge, three resistors
( P, Q, R ) are connected in three arms in
order and ( 4^{t h} ) arm ( mathrm{S} ) is formed by two
resistors ( s_{1} ) and ( s_{2} ) connected in
parallel. The condition for bridge to be balanced is: ( frac{P}{Q}= )
A ( cdot frac{Rleft(s_{1}+s_{2}right)}{s_{1} s_{2}} )
В. ( frac{s_{1} s_{2}}{Rleft(s_{1}+s_{2}right)} )
c. ( frac{R s_{1} s_{2}}{left(s_{1}+s_{2}right)} )
D. ( frac{left(s_{1}+s_{2}right)}{R s_{1} s_{2}} )
12
522A wire when connected to ( 220 mathrm{V} ) mains
supply has power dissipation ( P_{1} . ) Now
the wire is cut into two equal pieces which are connected in parallel to the same supply. Power dissipation in this
case is ( P_{2} ). Then ( P_{2}: P_{1} ) is
( A )
B. 4
( c cdot 2 )
D. 3
12
523f ( i=0.25 ) amp. in the fig the value of ( R )
is :-
( A cdot 48 Omega )
в. ( 12 Omega )
c. ( 120 Omega )
D. ( 42 Omega )
12
524A material ( B ) has twice the specific
resistance of ( A . ) A circular wire made of
( B ) has twice the diameter of a wire
made of ( A ). Then for the two wires to
have the same resistance, the ratio ( l_{B} / )
( l_{A} ) of their respective lengths must be:
( A )
B. 1/2
( c cdot 1 / 4 )
D.
12
525( mathbf{A} )
( 2.0 V ) potentiometer used for the
determination of internal resistance of
a ( 1.5 V ) cell. The balance point of the cell
in open circuit is ( 76 mathrm{cm} ). When a resistor
of ( 9.5 Omega ) is used in the external circuit of
the cell, the balance point shifts to ( 57 mathrm{cm} ) length of the potentiometer wire. Determine the internal resistance of the
cell
A ( .1 .7 Omega )
В. ( 2.5 Omega )
c. ( 1.5 Omega )
D. ( 0.5 Omega )
12
526Explain briefly the coil and magnet experiment to demonstrate electromagnetic induction.12
527A heater coil is cut into two equal parts
and only one part is now used in the heater. The heat generated will now be:
A. doubled.
B. four times
c. one-fourth
D. halved
12
528A current of 2 A passing through conductor produces 80 J of heat in 10 seconds. The resistance of the
conductor is –
A . ( 0.5 Omega )
B. 2Omega
( c .4 Omega )
D. 20Omega
12
529A battery of ( 10 mathrm{V} ) and internal resistance
( 0.5 Omega ) is connected across a variable
resistance R. The value of ( R ) for which
the power delivered in its maximum state, is equal to :-
A ( .0 .5 Omega )
в. ( 1 Omega )
c. ( 1.5 Omega )
D. ( 2.0 Omega )
12
530Assertion
In a meter bridge experiment, a high resistance is always connected in
series with a galvanometer.
Reason
As resistance increases, current
through the circuit increases.
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
531A steady current i passes through a linear conductor of uniform cross-
section. Any given segment of the conductor has
A. a net negative charge
B. a net positive charge
c. a zero net charge of any kind
D. a net charge proportional to the volume of the segment
12
532A table lamp of power 60 W consumed 9 (commerical) units of electricity in the month of April. For how many hours per day, on an average, was the lamp in
use?
( A cdot 1 h )
B. 3h
( c cdot 5 h )
( D cdot 6 h )
12
533Of the two bulbs in a house, one glows brighter than the other. Which of the two has a large resistance?
A. The bright bulb
B. The dim bulb
c. Both have the same resistance
D. The brightness does not depend upon the resistance
12
534Open circuit voltage of a source is 7.86 V and its short circuit current is 9.25 A. Find the current when an external
resistance of ( 2.4 Omega ) is connected
A . ( 1.4 mathrm{A} )
B. 1.82A
c. 2.01A
D. 2.4A
12
535The internal resistance of a cell of emf
( 1.5 V, ) if it can deliver a maximum
current of ( 3 A ) is
A . ( 0.5 Omega )
B. 4.5Omega
( c .2 Omega )
D. 1Omega
12
536Find ( C_{A B} ) if each capacitor is ( C ) in the
figure shown :
A. 3C
B. 2C
( c cdot c )
D. ( c / 2 )
12
537Find the emfs ( varepsilon_{1} ) and ( varepsilon_{2} ) in the circuit in
Figure. Also find the potential difference
of point ( b ) relative to point ( a )
12
538( mathbf{1 0 mu A s}= )
coulombs.
A ( cdot 10^{-4} )
-4
B. ( 10^{-5} )
( mathrm{c} cdot 10^{-3} )
D. ( 10^{-6} )
12
539When ( n ) number identical cell of emf ( E )
and internal resistance, ( r ) is connected
in parallel, the net internal resistance of the system will be
( A )
B . ( n r )
c. ( r / n )
D. ( n / r )
12
5405. If emf of battery is 100 V, then what was the resistance of
Rheostat adjusted at reading (2)? (i = 2 A, V = 20 V).
4A
10 20
30 40
(a) 10Ω
(c) 30 Ω
(b) 20 Ω
(d) 40 Ω
12
541The balancing length for a cell is ( 560 mathrm{cm} ) in a potentiometer experiment. When an external resistance of ( 10 Omega ) is connected
in parallel to the cell, the balancing length changes by ( 60 mathrm{cm} ). If the internal resistance of the cell is ( frac{N}{10} Omega, ) where ( N ) is an integer then value of ( mathrm{N} ) is
12
542Let ( C ) be the capacitance of a capacitor discharging through a resistor
R.Suppose ( t ) is the time taken for the energy stored in the capacitor to be reduced to half its initial value and t2 is
the time taken for the charge to reduce to one fourth its initial value.Then the
ratio t1/t2 will be
12
543Two metallic spheres of radii ( 2 mathrm{cm} ) and
( 6 mathrm{cm} ) are given charges ( 3 times 10^{-2} mathrm{C} ) and
( 7 times 10^{-2} C, ) respectively. If these are
connected by a conducting wire, the final charge on the bigger sphere is
A ( cdot 7.5 times 10^{-2} C )
В. ( 4 times 10^{-2} mathrm{C} )
c. ( 3.5 times 10^{-2} C )
D. ( 2 times 10^{-2} C )
12
544State whether the following statement
is True or False
The Sl unit of charge is coulomb.
12
545Find ( rho ) using ( a=frac{-n}{T} )
( mathbf{A} cdot rho propto T^{n} )
B ( cdot rho propto T^{n-1} )
c. ( rho propto T^{-n} )
D. ( rho propto frac{n}{T} )
12
546Different materials have
A. different resistivityyyy
B. same resistivity
c. O resistivity
D. none of the above
12
547Assertion
Kirchhoff’s junction rule can be applied to a junction of several lines or a point in a line.
Reason
When steady current is flowing, there is no accumulation of charges at any junction or at any point in a line.
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
548If a copper wire is stretched to make its
radius decrease by ( 0.1 % ), the percentage changes in its resistance is approximately
A . ( -0.4 % )
B. ( +0.8 % )
c. ( +0.4 % )
D. ( +0.2 % )
12
549A 10 V battery of negligible internal resistance is connected across a ( 200 mathrm{V} )
battery and a resistance of ( 38 omega ) as
shown in the figure. Find the value of the current in circuit.
12
550For a certain load, the true power is ( 150 W ) and the reactive power is ( 125 W ) The apparent power is
A. ( 19.52 W )
В. ( 195.2 W )
( mathrm{c} cdot 275 mathrm{W} )
D. 25W
12
551( 1 mathrm{mA}=_{-}-_{-}—^{mathrm{A}} )
( mathbf{A} cdot 10^{3} A )
B. ( 10^{-3} A )
( c cdot 10^{6} A )
D. ( 10^{-6} A )
12
552Each of the resistors shown in Figure
has resistance ( R ). Find the equivalent
resistance between ( A ) and ( B )
( ^{A} cdot frac{7 R}{4} )
в. ( frac{5 R}{4} )
c. ( frac{9 R}{4} )
D. ( frac{11}{4} )
12
553Which of the following sets has different dimensions?
A. Pressure, Young’s modulus, stress
B. Emf, potential difference, electric potential
c. Heat, work done, energy
D. Dipole moment, electric flux, electric field
12
554Match the following:
( begin{array}{ll}text { List- I } & text { List – II } \ text { a) Resistivity } & text { e) volt } \ text { b) Conductivity } & text { f) siemen } \ text { c) emf } & text { g) ohm-metre } \ text { d) conductance } & text { h) mho / metre }end{array} )
( A cdot a-e, b-f, c-g, d-h )
B. ( a-f, b-e, c-g, d-h )
( c cdot a-g, b-h, c-e, d-f )
( D cdot a-h, b-g, c-e, d-f )
12
555The three resistance of equal value are
arranged in the different combinations
shown below.
Arrange them in increasing order of power dissipation.
A. ( ||<|<| V<1 )
B. ( |<|<mid V<1 )
c. ( |<| V<|mid<| )
D. ( |<|mid<|<1 V )
12
556The number of free electrons in 1 c.c. of
Copper is
A. ( 8.4 times 10^{22} )
B. ( 5.8 times 10^{22} )
( mathbf{c} cdot 10^{15} )
D. ( 10^{20} )
12
557In a metallic conductor, electric current
is thought to be due to the movement of
A . ions
B. amperes
c. electrons
D. protons
12
558Three equal resistors connected in series across a source of e.m.f dissipate
10 watts of power. What will be the power dissipated in watts if the same resistors are connected in parallel
across the same source of e.m.f?
A. ( 10 mathrm{w} )
B. 30 W
c. ( 90 mathrm{w} )
D. ( frac{10}{3} W )
12
559A wire of resistance ( 20 Omega ) is covered with
ice and a voltage of ( 210 mathrm{V} ) is applied across the wire, then rate of melting the ice is
A. ( 0.85 mathrm{g} / mathrm{s} )
B. 1.92 ( g / ) s
c. ( 6.56 mathrm{g} / mathrm{s} )
D. All of these
12
560Two cells of emf ( 4 V ) and ( 2 V ) and
internal resistance ( 2 Omega ) and ( 1 Omega )
respectively are connected in parallel so
as to send the current in the same
direction through an external resistance of ( 10 Omega ). Find the potential difference across ( 10 Omega ) resistor.
12
561A steady current passes through a wire
of non-uniform cross-section. The
quantities which depend on the Area of
cross-section are:
A. Free electron density
B. Resistivity
C. Drift velocity
D. Charge crossing in a given time interval
12
562The number of turns in th coil of an ( a c )
generator is 5000 and the area of the
coil is ( 0.25 m^{2} . ) The coil is rotated at the
rate of 100 cycles/s in a magnetic field
of ( 0.2 T . ) The peak value of emf
generated is nearly:
A. ( 786 k V )
( V )
в. ( 440 mathrm{kV} )
c. ( 220 k V )
D. ( 157.1 k V )
12
563In a potentiometer experiment, the balancing length of a cell is ( 560 mathrm{cm} ) When an external resistance of ( 10 Omega ) is
connected in parallel to the cell, the balancing length changes by ( 60 mathrm{cm} . ) The internal resistance of a cell is
A . ( 1.4 Omega )
в. ( 1.6 Omega )
c. ( 0.12 Omega )
D. ( 1.2 Omega )
12
564An electric tea kettle has two electric
heating coils. When one of the coil is switched on the tea begins to boil in 6 minutes. When the other is switched on
the boiling begins in 8 minutes If both the coils are now arranged in series and switched on, boiling starts in
A . ( 24 / 7 ) minutes
B. 12 minutes
c. 14 minutes
D. 4 minutes
12
565A galvanometer is an instrument
capable to measure
A. small voltage
B. small current
( c ). both (a) and (b)
D. none of these
12
566If e.m.f of cell is ( boldsymbol{E} ) with internal
resistance ( r ) and external resistance is
( boldsymbol{R}, ) then terminal voltage will be :
A ( cdot frac{E r}{R+r} )
в. ( frac{E R}{R+r} )
c. ( E )
D. ( frac{E r R}{R+r} )
12
567Assertion
Voltmeter is much better than a
potentiometer for measuring emf of cell
Reason

A potentiometer draws no current while measuring emf of a cell.
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
568The e.m.f. of a cell is ( _{–}-_{-}- ) the voltage across its terminals when no current
flows. Fill in the blank.
A. more than
B. less than
c. equal to
D. none of these
12
569Assertion
Ohm’s law is not valid if current
depends on voltage non-linearly.
Reason
Ohm’s law is a fundamental law of
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
570Nichrome and copper wire of same
length and same radius are connected in series. Current ( I ) is passed through
12
571Steady current flows in a metallic conductor of non-uniform cross-section.
Which of the following quantities is a constant along the conductor?
A. Current
B. Current density
c. Electric field
D. Drift speed
12
572A galvanometer (coil resistance ( 99 Omega) )
is converted into a ammeter using a
shunt of ( 1 Omega ) and connected as shown in
the figure ( ( i ) ). The ammeter reads ( 3 A )
The same galvanometer is converted
into a voltmeter by connecting a
resistance of ( 101 Omega ) in series. This
voltmeter is connected as shown in
figure ( ( i i ) ). Its reading is found to be ( 4 / 5 )
of the full scale reading. Find the internal resistance ( r ) of the cell (in
ohms)
12
573There are a large number of cells available, each marked ( (6 V, 0.5 Omega) ) to be used to supply current to a device of resistance ( 0.75 Omega, ) requiring ( 24 A ) current. How should the cells be
arranged, so that power is transmitted to the load using minimum number of
cells?
A. Six rows, each containing four cells
B. Four rows, each containing six cells
c. Four rows, each containing four cells
D. Six rows, each containing Six cells
12
574The resistance of wire is 5 ohm at ( 50 C )
and 6 ohm at 100 C. The resistance of the
wire at ( 0 mathrm{C} ) willbe
A. 2 ohm
B. 1 ohm
c. 4 ohm
D. 3 ohm
12
575toppr 5
gate and from the door of the house.
Select the correct possible circuit(s)
required.
( A )
в.
( c )
( D )
12
576(a) Why are the connections between
the resistors in a meter bridge made of
thick copper strips?
(b) Why is it generally preferred to
obtain the balance point in the middle
of the meter bridge wire?
(c) Which material is used for the meter
bridge wire and why?
OR
A resistance of ( mathrm{R} Omega ) draws current from
a potentiometer as shown in the figure.
The potentiometer has a total
resistance ( R_{0} Omega . ) A voltage ( V ) is supplied
to the potentiometer. Derive an
expression for the voltage across ( mathrm{R} ) when the sliding contact is in the
middle of the potentiometer.
12
577Find equivalent resistance between ( mathbf{X} )
and ( Y )
( A )
B. R/L
( c cdot 2 R )
5. 5
12
578Appliances based on heating effect of current work on
A. only A.c.
B. only D.C.
c. both A.c. and D.c.
D. none of these
12
579The circuit given below is for the operation of an industrial fan. The resistance of the fan is 3 ohm. The
regulator provided with the fan is a
fixed resistor and a variable resistor in
parallel. Under what value of the variable resistance given, power transferred to the fans will be
maximum? The power source of the fan
is a dc source with internal resistance
of 6ohm
A . ( 3 Omega )
B.
( c cdot alpha )
D. 6.9
12
580A carbon resistor of ( (47 pm 4.7) k Omega ) is to
be marked with rings of different
colours for its identification. The colour
code sequence will be:
A. Yellow-Green-Violet-Gold
B. Violet-Yellow-Orange-Silver
c. Green-orange-violet-Gold
D. Yellow-violet-orange-silver
12
581Four bulbs marked ( 40 W, 250 V ) are
connected in series with ( 250 V ) mains,
the total power consumed is
A. ( 10 W )
в. ( 40 W )
c. ( 320 W )
D. ( 160 W )
12
582A cell of emf ( 1.5 % ) and internal
resistance ( 0.5 Omega ) is connected to a
conductor whose ( V-I ) graph is an
shown in the figure. Then, the terminal
voltage of the cell is
( mathbf{A} cdot 0.75 V )
в. ( 1.0 V )
c. ( 1.25 V )
D. ( 1.5 V )
12
583Find the potential gradient along AB
A ( cdot 0.1 mathrm{Vcm}^{-1} )
B. ( 0.03 mathrm{Vcm}^{-1} )
c. ( 0.04 mathrm{Vcm}^{-1} )
D. ( 0.02 mathrm{vcm}^{-1} )
12
584The resistivity of a potentiometer wire
is ( rho ) and the area of cross section of the
wire is ( A . ) If the current flowing in the circuit is ( I ), then potential gradient will
be
A. ( I A )
в. ( I A / rho )
c. ( I rho / A )
D. IA
12
585toppr ( t )
supply ( ): )
( A )
B.
( c )
( D )
12
586The resistance of a coi is ( 4.2 Omega ) at
( 100^{circ} mathrm{C} ) and the temperature coefficient
of resistance of its material is
( 0.004 /^{circ} mathrm{C} . ) Its resistance at ( 0^{circ} mathrm{C} )
A . ( 6.5 Omega )
B. 3Omega
( c .5 Omega )
D. 4Omega
12
587A cell sends a current through a resistance ( R ) for time ( t ; ) next the same
cell sends current through another resistance ( r ) for the heat is developed in
both the resistance, then the internal
resistance of the cell is:
A. ( (R+r) / 2 )
в. ( (R-r) / 2 )
c. ( sqrt{R r} )
D. ( sqrt{R r} / 2 )
12
588The cell has an emf of ( 2 V ) and the
internal resistance of this cell is ( 0.1 Omega ), i is connected to a resistance of ( 3.9 Omega ), the
voltage across the cell will be
( mathbf{A} cdot 0.5 V )
в. ( 1.9 V )
c. ( 1.95 V )
D. ( 72 ~ V )
12
589If six identical cells each having an emf
of ( 6 V ) are connected in parallel, the emf of the combination is
A . ( 1 v )
B. 36V
( c cdot 1 / 6 v )
D. ( 6 v )
12
590A cell of constant ( e m f ) first connected
of a resistance ( R_{1} ) and then connected
to a resistance ( boldsymbol{R}_{2} ). If power delivered in
both cases is same then the internal
resistance of the cell is:
A ( cdot sqrt{R_{1} R_{2}} )
в. ( sqrt{frac{R_{1}}{R_{2}}} )
c. ( frac{R_{1}-R_{2}}{2} )
D. ( frac{R_{1}+R_{2}}{2} )
12
591Does the value of resistance of a
conductor depend upon the potential difference applied across it or current
passes through it?
12
592A graph is plotted between the potential difference (applied across the ends of a conductor) and the current (following through the conductor). The graph is a straight line
A. having intercepts on both axes
B. having an intercept on the X-axis
c. having an intercept on the Y-axis
D. none of these
12
593A substance that prevents electric
current from passing through it is called
A. a conductor
B. an insulator
c. a semiconductor
D. a superconductor
12
594A voltmeter of resistance ( 998 Omega ) is
connected across a cell of emf ( 2 mathrm{V} ) and
internal resistance 2Omega. The potential difference across the voltmeter is?
( mathbf{A} cdot 1.99 mathrm{v} )
B. 3.5v
c. ( 5 v )
D. ( 6 v )
12
595A current ( i ) passes through a wire of length ( L, ) radius ( R ) and resistively ( rho . ) The rate of heat generated is
A ( cdot frac{i rho L}{pi r^{2}} )
В. ( i^{2}left(frac{L rho}{pi r^{2}}right) )
( ^{mathbf{c}} cdotleft(frac{i^{2} rho L}{r}right) )
D. none of these
12
596The value of current ( i ) in the given
circuit is:
A. zero
B. 5 Amp.
c. 7 Amp
D. 11 Amp
12
597Average value of current or voltage over
a half cycle can be zero also. This depends on the time interval (of course
T/2) over which average value is to be found.Why?
12
598An electric bulb of ( 15 mathrm{V} ) is connected to a
battery of ( 15 mathrm{V} ) which has negligible resistance. If the resistance offered by
the bulb is ( 5 Omega ) the power of the bulb is
( ldots ) W.
A . 225
B. 75
( c .30 )
D. 45
12
599A potentiometer wire ( 10 mathrm{m} ) long has a resistance of ( 40 Omega . ) It is connected in
series with a resistance box and a ( 2 mathrm{V} )
storage cell. If the potential gradient along the wire is ( 0.1 mathrm{mV} / mathrm{cm}, ) the resistance in the box is
( A cdot 760 Omega )
B. 260Omega
c. ( 1060 Omega )
D. ( 960 Omega )
12
600Two identical loops ( A ) and ( B ) lying in the
same plane carry equal currents. Four points ( P, Q, R ) and ( S ) are in the plane of
the loops. Choose the correct statement
A. The field at P must be out of the plane of the paper
B. The field at ( Q ) must be into the plane of the paper
c. the field at ( R ) must be out of the plane of the paper
D. The field at ( s ) must be out of the plane of the paper
12
601In a metre bridge experiment null point is obtained at ( 40 mathrm{cm} ) form one end of the
wire when resistance ( X ) is balanced
against another resistance Y. If ( mathrm{X}<mathrm{Y} ) then the new position of the null point from the same end, if one decides to
balance a resistance of ( 3 mathrm{X} ) against ( mathrm{Y} ) will be close to
( mathbf{A} cdot 80 mathrm{cm} )
B. ( 75 mathrm{cm} )
( c cdot 67 mathrm{cm} )
D. ( 50 mathrm{cm} )
12
602A wire is cut into three equal parts and then connected in parallel with the
same source. How will it
(i) resistance and resistivity gets
affected?
(ii) How would the total current and the
current through the parts change?
12
603An electrical device operate at 12 A current and ( 120 mathrm{V} ) D.C. If it is connected
with ( 250 mathrm{V} ) and ( 30 mathrm{Hz} ) AC. then power consumption:
A. 625 w
B. 1250 W
( c . ) 6250 ( w )
D. zero
12
604The reading of ammeter is ( x ) amperes
and that of voltmeter is 20 volts shown
in the figure. Then ( x ) is:
( A cdot 4 )
( B )
( c cdot 8 )
( D )
12
605Match the entries in column A with
appropriate ones from column B.
12
606Current flow takes place across a
conductor only when a p.d in maintained across its two ends.
A. True
B. False
12
607A battery of internal resistance ( 4 Omega ) is
connected tot he network of resistance
as shown. In order to give the maximum power to the network, the value of ( operatorname{Rin} Omega )
should be:
( A cdot frac{4}{9} )
( B cdot frac{8}{9} )
( c cdot 2 )
( D cdot 18 )
12
608The terminal voltage of a cell in open circuit condition is
A. Less than its emf
B. More than its emf
c. Equal to its emf.
D. Depends on its internal resistance.
12
609Resistance of a metal wire of length 1 m is ( 104 Omega ) at ( 20 C . ) If the diameter of the
wire is 0.15 mm, find the resistivity of
the metal at that temperature.
12
610A conductor wire, having ( 10^{29} ) free
electrons per ( m^{3} ) carries a current of
( 20 A . ) If the cross-section of the wire is
( 1 m m^{2}, ) then the drift velocity of
electrons will be of the order of:
A ( cdot 10^{-5} m s^{-1} )
B. ( 10^{-3} mathrm{ms}^{-1} )
c. ( 10^{-4} m s^{-1} )
D. ( 10 m s^{-1} )
12
611Define mobility of a charge carrier
What is its relation with relaxation
time?
12
612How does the resistance of a wire vary
with its cross sectional area.
12
613When is the Wheatstone’s bridge said to be most sensitive?12
614can be used to verify Ohm’s law :-
( A )
B.
( c )
( D )
12
615In the absence of an electric field, the mean velocity of free electrons in a
conductor at absolute temperature ( (boldsymbol{T}) )
is
A . zero
B. independent of ( T )
c. proportional to ( T )
D. proportional to ( T^{2} )
12
616A student while performing an experiment was surprised to find that when two identical cells are either
connected in series or in parallel across
a ( 2 Omega ) resistor, the same current passes through the resistor. What is the
internal resistance of each cell?
A . ( 2 Omega )
B. ( 4 Omega )
( c cdot 1 Omega )
D. 3Omega
12
617Find the voltage ( V_{a b} ) in the circuit shown
in figure.
( A cdot+3 V )
( B .-3 v )
( c cdot+6 v )
( 0 .-6 )
12
618Four wires of the same diameter are
connected, in turn, between two points maintained at a constant potential difference. Their resistivity’s and lengths are; ( rho ) and ( L(text { wire } 1), 1.2 rho ) and 1.2L (wire 2), ( 0.9 rho ) and 0.9L (wire 3) and
( rho ) and ( 1.5 mathrm{L} ) (wire 4 ). Rank the wires
according to the rates at which energy is dissipated as heat, greatest first.
A ( .4>3>1>2 )
в. ( 4>2>1>3 )
c. ( 1>2>3>4 )
D. ( 3>1>2>4 )
12
619If the wire in the experiment to determine the resistivity of a material using metre bridge is replaced by copper or hollow wire the balance point
i.e. null point shifts
A. to right
B. to left
c. at same point
D. None of these
12
620Draw the circuit diagram of a meter bridge to explain how it is based on
Wheatstone bridge.
12
621n a circuit given below calculate the
potential difference between points ( B )
and ( D ). Also find the potential
difference across the terminals of ( G )
and ( boldsymbol{H} )
12
622Two cells, having emfs of ( 10 V ) and ( 8 V )
respectively, are connected in series
with a resistance of ( 24 Omega ) in the external
circuit. If the internal resistances of
each of these cells in ohm are ( 200 % ) of
the value of their emf’s respectively,
find the terminal potential difference
( operatorname{across} 8 V ) battery.
A ( .0 .3 A, 3.2 V )
B. ( 0.5 A, 3.2 V )
c. ( 0.3 A, 1.2 V )
D. ( 0.5 A, 2.2 V )
12
623Ashokbhai goes to an electric shop to buy an electric bulb to obtain light in a small room of his home. Which of the
following statement is scientifically
correct
A. Give bulb of ( 60 mathrm{V} )
B. Give bulb of ( 60 mathrm{J} / mathrm{s} )
c. Give bulb of ( 60 A )
D. Give bulb of ( 60 mathrm{W} )
12
624The diameter of a copper wire is ( 2 mathrm{mm} ) a steady current of 6.25 A is generated by ( 8.5 times 10^{28} / m^{2} ) electron flowing
through it. Calculate the drift velocity of conduction electrons.
12
Does pure water conduct electricity? If not, what can we do to make it conduct?
12
626Assertion: A current flows in a
conductor only when there is an electric field within the conductor.

Reason : The drift velocity of electron in presence of electric field decreases.
A. Both (A) and (R) are true and
(R) is the correct explanation of
B. Both (A) and (R) are true but (R) is not the correct explanation of A
c. (A) is true but (R) is false
D. (A) is false but (R) is true

12
627Which device is used to measure the
potential difference between two points of a conductor in the laboratory?
A. Voltameter
B. Ammeter
c. Potentiometer
D. Galvanometer
12
628Which of the following quantities do not change when a resistor connected to a battery is heated due to the current?
A. Drift speed
B. Resistivity
c. Resistance
D. Number of free electrons
12
629The device used to detect and measure
electric charges is
12
630Find the equivalent resistance in between ( A ) and ( B ) for the circuit shown in
the figure.
A . ( 30 Omega )
B. ( 5 Omega )
c. ( 10 Omega )
D. 20Omega
12
631Consider the potentimeter circuit
arranged as in figure. The potentometer
wire is ( 600 mathrm{cm} ) long.
(a) At what distance from the point ( boldsymbol{A} )
should the jockey touch the wire to get zero deflection in the galvanometer?
(b) If the jockey touches the wire at a
distance of ( 560 mathrm{cm} ) from ( mathrm{A} ), what will be
the current in the galvanometer?
12
632Assertion
Ohm’s law is applicable for all conducting elements
Reason
Ohm’s law is a fundamental law.
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
633(a) Why are the connections between the resistor in a meter bridge made of thick copper strips?
(b) Why is it generally preferred to obtain the balance point in the middle of the meter bride wire?
(c) Which material is used for the meter
bridge wire and why?
12
634connected across a ( 4 m ) long uniform
wire having resistance ( 4 Omega / m . ) The cells
of small emfs ( epsilon_{1}=2 V ) and ( epsilon_{2}=4 V )
having internal resistance ( 2 Omega ) and ( 6 Omega )
respectively, are connected as shown in
the figure. If galvanometer shows no
deflection at the point ( N, ) the distance
of point ( N ) from the point ( A ) is equal to
( A cdot underline{1}_{-} )
( B cdot 1 )
( -n )
c. ( 25 mathrm{cm} )
D. 50
12
635Four bulbs marked ( 40 W, 250 V ) are
connected in series with ( 250 V ) mains,
the total power consumed is
A. ( 10 W )
в. ( 40 W )
c. ( 320 W )
D. ( 160 W )
12
636Space between two concentric conducting spheres of radii a and ( b(b>a) ) is filled with a medium of
resistivity ( rho . ) The resistance between the
two spheres will be :
A ( cdot frac{rho}{4 pi}left(frac{1}{a}-frac{1}{b}right) )
в. ( frac{rho}{2 pi}left(frac{1}{a}-frac{1}{b}right) )
c. ( frac{rho}{2 pi}left(frac{1}{a}+frac{1}{b}right) )
D. ( frac{rho}{4 pi}left(frac{1}{a}+frac{1}{b}right) )
12
637Two resistors of resistances ( 2 Omega ) and ( 6 Omega )
are connected in parallel. This
combination is then connected to a
battery of emf ( 2 mathrm{V} ) and internal
resistance ( 0.5 Omega . ) What is the current
flowing through the battery?
A. 4 A
в. ( frac{4}{3} A )
c. ( frac{4}{17} A )
D. 1A
12
638Two batteries of emf ( boldsymbol{E}_{1} ) and ( boldsymbol{E}_{2}left(boldsymbol{E}_{2}>right. )
( E_{1} ) ) and internal resistance ( r_{1} ) and ( r_{2} )
respectively are connected in parallel as shown in figure
12
639The Figure represents a part of a closed circuit. The p.d. In volts between the
points ( A ) and ( B ) i.e. ( V_{A}-V_{B} ) is
12
640You are given a resistance wire of length ( 100 mathrm{cm} ) and a battery of negligible internal resistance. In which of the
following cases is the largest amount of heat generated?
A. When the wire is divided in two parts and both the parts are connected to the battery in parallel
B. When the wire is connected to the battery directly
c. when the wire is divided in to four parts and all the fou parts are connected in parallel to the battery
D. When only half of the wire is connected to the battery
12
641A ( 10 V ) cell of negligible internal
resistance is connected in parallel
across a battery of emf ( 200 mathrm{V} ) and
internal resistance ( 38 Omega ) as shown in the
figure. Find the value of current in the
circuit.
12
( mathbf{A} cdot 1 / 5 mathrm{Vm}^{-1} )
B. 2/5 Vm ( ^{-1} )
c. ( 3 / 5 mathrm{Vm}^{-1} )
D. ( 4 / 5 mathrm{Vm}^{-1} )
12
643Find the value of currents ( l_{1}, l_{2} ) and ( l_{3} )12
644Find the potential at the centre of arrangement having 6 charged particles of ( Q=5 mu C ) each arranged in
the form of a hexagon of side length 0.1
( mathrm{m} )
12
645Two cells ( A ) and ( B ) of e.m.f ( 2 V ) and ( 1.5 V )
respectively, are connected as shown in figure through an external resistance
10Omega. The internal resistance of each cell
is 5Omega. The potential difference ( V_{A} ) and
( V_{B} ) across the terminals of the cells ( A )
and B respectively are.
A ( cdot V_{A}=2.0 V, V_{B}=1.5 mathrm{V} )
B . ( V_{A}=2.12 V, V_{B}=1.375 V )
C ( . V_{A}=1.875 V, V_{B}=1.625 V )
D. ( V_{A}=1.875 V, V_{B}=1.375 V )
12
646Assertion
The electric bulbs glows immediately
when switch is on.
Reason
The drift velocity of electrons in a
metallic wire is very high.
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
647A negligibly small current is passed through a wire of length ( 15 mathrm{m} ) and uniform cross-section ( 6.0 times 10^{-7} m^{2} )
and its resistance is measured to be
5.0Omega. What is the resistivity of the material at the temperature of the experiment?
12
648The value of e is
A . ( 1.36 mathrm{v} )
B. 2.63
c. ( 1.83 mathrm{v} )
D. none
12
649If a copper wire is stretched to make it
( 0.1 % ) longer, the percentage increases in resistance will be
A . 0.2%
B. 2%
c. 1%
D. 0.1%
12
650A potentiometer wire of length ( L ) and a
resistance ( r ) are connected in series
with a battery of e.m.f. ( boldsymbol{E}_{0} ) and ( mathbf{a} )
resistance ( r_{1} . ) An unknown e.m.f. ( boldsymbol{E} ) is
balanced at a length ( l ) of the
potentiometer wire. The e.m.f. ( boldsymbol{E} ) will be
given by:
A ( cdot frac{L E_{0} r}{left(r+r_{1}right) l} )
в. ( frac{L E_{0} r}{l r_{1}} )
( mathbf{c} cdot frac{E_{0} r}{left(r+r_{1}right)} cdot frac{l}{L} )
D. ( frac{E_{0} l}{L} )
12
651Five cells of emf ( 1.5 mathrm{V} ) and internal
resistance 0.2 ohm are connected in
series. The maximum current that can
be delivered is
A . 7.5A
B. 1.5A
( c cdot 4 A )
D. 2A
12
652What is the colour code of a corbon
resistor having a resistance of ( 470 Omega )
and a tolerance of 5%?
12
653The lengths of two wires made of the same material are in the ratio ( 2: 1 . ) If
the masses of the two wires are in the
ratio ( 1: 8, ) find the ratio of their
resistances
( mathbf{A} cdot 1: 16 )
B. 32: 1
( mathbf{c} cdot 16: 1 )
D. 1: 32
12
654In order to increase the resistance of a
given wire of uniform cross-section to four times its value, a fraction of its
length is stretched uniformly till the full length of the wire becomes ( frac{3}{2} ) times the original length.What is the value of this
fraction?
( A cdot frac{1}{4} )
B. ( frac{1}{8} )
( c cdot frac{1}{16} )
D. ( frac{1}{6} )
12
655In the given figure, when galvanometer
shows no deflection, the current (in
ampere flowing through ( 5 Omega )
resistance will be
A . ( 1.7 A )
В. ( 0.6 A )
( c .0 .9 A )
D. ( 1.2 A )
12
656A battery and a variable resistor are in
series with a small fan. A switch is
closed, and the fan runs. When the variable resistor is moved slightly to the left, the fan slows down a little. When
the variable resistor is moved slightly to the right, the fan speeds up a little. If the variable resistor in the circuit is set
all the way to the right, what happens in the circuit?
I. The fan runs faster
II. The voltage decreases.
III. The current increases.
A . I only
B. Il only
c. I and III only
D. I I and III only
E . I, II, and III
12
657Consider a neutral conducting sphere. A positive point charge is placed outside the sphere. The net charge on the sphere is then,
A. negative and distribute uniformly over the surface of the sphere
B. negative and appears only at the sphere closest to the point charge
c. negative and distribute non-uniformly over the entire surface of the sphere
D. zero
12
658Which of the following is the correct one
( ? )
A. The resistivity of an alloy is equal that of pure metals.
B. The resistivity of an alloy is lower than that of pure metals
c. The resistivity of an alloy is higher than that of pure metals
D. None of above
12
659( = )

( L_{k} )

12
660The diagrams show different resistor
arrangements.

Which arrangement has the smallest
combined resistance?
( A )
B.
( c )
( D )

12
661Consider the following statements A and ( mathrm{B} ) and identify the correct answer
A: Thermistors can have only -ve temperature coefficient of resistors.
B : Thermistors with -ve temperature coefficients of resistance are used as
resistance thermometers to measure
low temperature of the order of ( 10 mathrm{K} )
A. 1 both ( A ) and ( B ) are true
B. 2) both A and B are false
c. 3 ) A is true and ( B ) is false
D. 4 ) A is false, but ( B ) is true
12
662A cell of emf ( E ) volts with no internal
resistance is connected to a wire of
uneven cross-sectional area. The wire
has three sections of equal length. The radius of the middle section is ( a )
and the other are ( 2 a ). The ratio of the
potential difference across the middle section to any other section is
A .2: 1
B . 4: 1
c. 1: 2
D. 1: 4
12
663Define e.m.f. of a cell. How can you compare the emf of two cells using potentiometer?12
664In a meter bridge with a standard resistance of ( 5 Omega ) in the left gap, the ratio of balancing lengths on the meter bridge wire is ( 2: 3 . ) The unknown
resistance is
A . ( 3.3 Omega )
B. ( 7.5 Omega )
c. ( 10 Omega )
D. 15Omega
12
665You are given three bulbs ( 25 mathrm{W}, 40 mathrm{W} ) and ( 60 mathrm{W} ). Which of them has the
lowest resistance?
A. 25 watt bulb
B. 40 watt bulb
c. 60 watt bulb
D. Insufficient data
12
666The dry cell of E.M.F ( 12 V ), is connected
in series to a ( 3 Omega ) and a ( 6 Omega ) resistor
Calculate the total power supplied by
the dry cell.
( mathbf{A} .9 W )
B. ( 72 mathrm{W} )
c. ( 16 W )
D. ( 2 W )
12
667Each of Kirchoff’s two laws presumes
that some quantity is conserved.

Which row states Kirchhoff’s first law
and names the quantity that is
conserved?

This question has multiple correct options
A. Statement: the algebraic sum of currents into a junction is zero ; quantity : charge
B. statement: the algebraic sum of currents into a junction is zero ; quantity : energy
c. statement : the e.m.f in a loop is equal to the algebraic sum of the product of current and resistance round the loop ; quantity : charge
D. statement: the e.m.f in a loop is equal to the algebraic sum of the product of current and resistance round the loop ; quantity : energy

12
668In the circuit shown in Figure the heat
produced in resistance R1 can be measured by
A. connecting both voltmeter and an ammeter in parallel to R1
B. both voltmeter in series with ( mathrm{R} 1 ) and voltmeter in parallel to both R1 and R2
C. connecting ammeter in parallel to R1 and voltmeter in series with R1
D. connecting voltmeter in parallel to R1 and ammeter in series with R1
12
669A domestic electric circuit has a fuse of
5 A. What is the maximum number of
( mathbf{1 0 0} W(mathbf{2 2 0} V) ) bulbs that can be safely used in the circuit?
12
670The arm PQ can revolve with uniform
speed continuously about P round the
circular uniform potentiometer track
XYZ. The voltage between RS will vary
with respect to time:
A. sinusoidally
B. Linearly
c. Rectangularly
D. Like saw tooth
12
671The length and area of cross -section of a conductor are doubled, then its
resistance is
A. halved
B. unchanged
c. doubled
12
672How will you compare the e.m.f of two cells using a potentiometer?12
673Resistivity is
A. an extensive property
B. intensive property
C . elastic property
D. none of the above
12
674It takes 16 min to boil some water in
an electric kettle. Due to some defect it
becomes necessary to remove ( 10 % ) turns of the heating coil of the kettle. After repairs, how much time will it take
to boil the same mass of water?
A. 17.7 min
B. 14.4 min
c. 20.9 min
D. 13.7 min
12
675What is the power gain?12
676In the metre bridge experiment of resistances, the known and unknown resistances are inter-changed. The error so removed is:
A. end correction
B. index error
c. due to temperature effect
D. random error
12
677Primary circuit of potentio meter is as
shown in the diagram find potentia
12
678Two cells of emfs ( E_{1} ) and ( E_{2} ) are
connected in series. Their internal
resistances are ( r_{1} ) and ( r_{2} ) respectively. Compute the equivalent emf and equivalent internal resistance.
12
679What is the equivalent resistance of the system about ( A ) and ( C ? )
( A )
( B . r )
2
( c cdot 3 r )
2
D. ( 2 r )
12
680Find the ratio of the power developed in
segment AE to that in segment HM.
( A )
B. 2
( c cdot 3 )
( D cdot 4 )
12
681In a meter bridge experiment ( S ) is a
standard resistance. ( boldsymbol{R} ) is a resistance
wire. It is found that balancing length is ( l=25 mathrm{cm} . ) If ( R ) is replaced by a wire of
half length and half diameter that of ( boldsymbol{R} )
of same material, then the balancing
distance ( left.l^{prime} text { (in } c mright) ) will now be
12
682The practical unit of resistance is ( Omega ) and ( 1 Omega ) is equal to:
A ( cdot 10^{18}_{e m u} )
В. ( 10^{9} )ети
( mathbf{c} cdot 10^{15} e m u )
D. none of these
12
683Name and define unit for electric
current
12
684In this circuit, when certain current
flows, the heat produced in ( 5 Omega ) is ( 4.05 J )
in a time ( t . ) The heat produced in ( 2 Omega ) coil
in the same time interval is
A . 5.76
в. 1.44
( c .2 .88 )
D. 2.02
12
685Consider the following two statements:
(A) Kirchhoff’s Junction Law follows
from conservation of charge.
(B) Kirchhoff’s Loop Law follows from conservative nature of electric field
A. Both A and B are correct
B. A is correct but B is wrong
c. A is correct but A is wrong
D. Both A and B are wrongg
12
686Power dissipated in the circuit shown in the figure 30 watt. The value of R is
A . ( 5 Omega )
B. ( 15 Omega )
( c cdot 10 Omega )
D. 20 ( Omega )
12
687Consider the following two statements:
1) Kirchoff’s junction law follows from
the conservation of charge
2) Kirchoff’s loop law follows from the conservation of energy. Which of the following is correct?
A. both 1 and 2 are wrong
B. 1 is correct and 2 is wrong
C. 1 is wrong and 2 is correct
D. both 1 and 2 are correct
12
688Measure of the opposition to the flow the free electron is known as
A. current
B. Resistance
c. conductance
D. Capacitance
12
689Which are good insulators?
This question has multiple correct options
A. wood
B. copper
c. human body
D. glass
12
690Variation of resistance of the conductor
with temperature is as shown

The temperature co-efficient ( (alpha) ) of the
conductor is
( A cdot frac{R_{0}}{m} )
В ( cdot m R_{o} )
( mathbf{c} cdot m^{2} R_{o} )
D. ( frac{m}{R_{n}} )

12
691The circuit diagram shows that
resistors ( 2 Omega, 4 Omega ) and ( R Omega ) connected to
a battery of e.m.f. 2 V and
internal resistance ( 3 Omega ). A main
current of 0.25 A flows through the
circuit. What is the p.d. across the ( R Omega )
and ( 2 Omega ) resistor?
A. ( 0.25 vee, 0.5 mathrm{V} )
B. 0.25 V, 0.25 V
( c cdot 2 v, 1 v )
D. ( 0.5 vee, 0.25 )
12
692Resistance of a metallic conductor
depends on
A. Its length
B. Its area of cross section
c. Temperature
D. All the above
12
693A cell, an ammeter and a voltmeter are
all connected in series. The ammeter
reads a current I and the voltmeter a
potential difference V. If a torch bulb is connected across the voltmeter, then.
A. Both I and v will increase
B. Both I and V will decrease
c. I will increase but ( V ) will decrease
D. I will decrease but V will increase
12
694The resistance of a hot tungsten filament is about 10 times the cold
resistance. What will be the resistance
of ( 100 W, 200 V ) lamp when not in use?
A . ( 20 Omega )
B. ( 40 Omega )
c. ( 200 Omega )
D. ( 400 Omega )
12
695What is the resultant resistance of the
given circuit ?
A . ( 20 Omega )
B. ( 8 Omega )
( mathbf{c} .7 .2 Omega )
D. ( 12 Omega )
12
696A straight conductor of uniform cross-
section carried a current I. Let
s=specific charge of an electron. The momentum of all the free electrons per
unit length of the conductor, due to their drift velocities only, is
A . Is
B. ( 1 / s )
c. ( sqrt{I / s} )
D. ( (I / s)^{2} )
12
697Derive the condition of balance for
Wheatstone bridge.
12
698Rate at which electric work is done is
A. Potential difference
B. Energy
c. Power
D. All
12
699( mathbf{A} )
( 24 V ) battery having internal resistor of ( X Omega ) is connected to a ( 4 Omega ) resistor,
causing a current of ( 5 A ). Find out the
value of ( boldsymbol{X} ) ?
( mathbf{A} cdot 0 W )
B. ( 0.8 W )
c. ( 0.4 W )
D. ( 1.6 W )
E . ( 1.2 W )
12
700The value of the current ( boldsymbol{I}_{1}, boldsymbol{I}_{2} ) and ( boldsymbol{I}_{3} )
flowing through the circuit given below
is?
A ( cdot I_{1}=-3 A, I_{2}=2 A, I_{3}=-1 A )
B . ( I_{1}=2 A, I_{2}=-3 A, I_{3}=-1 A )
C ( . I_{1}=3 A, I_{2}=-1 A, I_{3}=-2 A )
D ( cdot I_{1}=1 A, I_{2}=-3 A, I_{3}=-2 A )
E ( cdot I_{1}=2 A, I_{2}=-1 A, I_{3}=-3 A )
12
701Assertion
When the radius of a copper wire is doubled, its specific resistance is increased.
Reason
Specific resistance is independent of cross-section of material used.
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
702The resistance of one ohm is very
approximately equal to that of a column of mercury ( 1.06 m ) long and of
uniform cross-section of one hundredth
of ( 1 mathrm{cm}^{2} ). Find the resistivity of mercury.
A ( cdot 6.4 times 10^{-7} Omega m )
В . ( 7.4 times 10^{-7} Omega m )
c. ( 9.4 times 10^{-7} Omega m )
D. ( 2.4 times 10^{-7} Omega m )
12
703If a copper ring is moved towards the north pole of a bar magnet, then:
A. the ring will not be affected
B. the ring will become warm
c. an alternating current will flow in the ring
D. the ring will be positively charged
12
704The figure below shows a variable
resistor in a dimmer switch.
How would you turn the switch to make
the lights: ( (a) ) brighter, and
(b) dimmer? Explain.
12
705Calculate the amount to heat produced per second when a bulb of ( 50 mathrm{W}, 200 mathrm{V} ) glows assuming that only ( 20 % ) of the electric energy is converted into light.
A. 20
B. 400
( c . ) 50
D. 200
12
706Show how you would connect 3 resistors
each of resistance 6 ohm, so that the
combination has a resistance of (i) 9
ohm
(ii) 4 ohm
12
707Keeping the length of the conductor constant, if the radius of the conductor is doubled, then its resistance becomes
A. Double
c. Half
D. Four times less
12
708The graph between potential difference and current for a conductor is a straight line passing through the origin. Which law is illustrated by such a graph?
A. Law ofcombination of resistances
B. Henry’s law
c. ohm’slaw
D. Joule’s law ofheating
12
709( n ) identical cells each of electromotive
force ( e ) and internal resistance ( r ) are
connected in series of this combination
The current through ( V ) is:
A ( cdot frac{2 e}{n} )
в. ( frac{n e}{n R+r} )
c. ( frac{e}{R+n r} )
D. ( frac{n e}{R+r} )
12
710The equivalent capacitance between
points ( X ) and ( Y ) in figure shown is :
( A )
В. ( 4 mu F )
c. ( frac{18}{5} mu F )
D. none of these
12
711Two metallic wires ( A ) and ( B ) of equal
materials, having resistivities ( rho ) and ( 2 rho ) temperature coefficients of resistivities ( 2 alpha ) and ( alpha ) are connected in series. The
temperature coefficient of resistance of the composite wire equals:
( ^{mathrm{A}} rho_{e q}=frac{3}{2} rho )
в. ( quad alpha_{e q}=frac{3}{2} )
( c cdot rho_{e q}=3 rho )
D. ( _{alpha_{e q}}=frac{4}{3} alpha )
12
712If ( i_{1}=3 sin omega t ) and ( i_{2}=4 cos omega t, ) then ( i_{3} )
is –
( mathbf{A} cdot 5 sin left(omega t+53^{circ}right) )
B. ( 5 sin left(omega t+37^{circ}right) )
( mathbf{c} cdot 5 sin left(omega t+45^{circ}right) )
( mathbf{D} cdot 5 cos left(omega t+53^{circ}right) )
12
713The current that passes through 20 ohm resistance when it is connected in
parallel with a 30 ohm resistance and this set is connected to a battery of ( 2 mathrm{V} )
is
A . ( 0.2 A )
B. ( 0.3 mathrm{A} )
c. ( 0.1 mathrm{A} )
D. 0.016A
12
714In the Bohr’s model of hydrogen atom, the electron moves around the nucleus
in a circular orbit of-radius ( 5 times 10^{-11} )
meters. If its time period is ( 1.5 times 10^{-16} )
sec, then current associated with the
electron motion is
A. zero
B. ( 1.6 times 10^{-19} A )
c. 0.17 А
D. ( 1.07 times 10^{-3} A )
12
715In the circuit shown the resistance ( R )
has a value that depends on the current.
Specifically, R is 20 ohms when I is zero and the increase in resistance in ohms
is numerically equal to one half of the
current in amperes. What is the value of current I in circuit?
A. 8.33 amp
B. 10 amp
c. 12.5 amp
D. 18.5 amp
12
716If 2.2 kilowatt power is being transmitted at ( 44 mathrm{KV} ) on a ( 20 Omega ) line,
then power loss will be:
A. 0.1 watt
B. 1.4 watt
c. 100 watt
D. 0.05 watt
12
717A wire of uniform cross-section has a
resistance of ( R ). If it is drawn to three
times the length, but the volume remains constant, what will be its
resistance?
( mathbf{A} cdot 3 R Omega )
B. ( 5 R Omega )
( mathbf{c} .7 R Omega )
D. ( 9 R Omega )
12
718Two cells of emf ( boldsymbol{E}_{1} ) and ( boldsymbol{E}_{2}left(boldsymbol{E}_{1}>boldsymbol{E}_{2}right) )
are connected shown in figure. When a potentiometer is connected between ( mathbf{A} ) and ( mathrm{B} ), the balancing length of the
potentiometer wire is ( 300 mathrm{cm} . ) On connecting the same potentiometer between ( A ) and ( C, ) the balancing length
is ( 100 mathrm{cm} . ) The ratio ( E_{1} / E_{2} ) is
A . 3: 1
B. 1: 3
( c cdot 2: 3 )
D. 3: 2
12
719A ( 500 W ) heating unit is designed to operate on a ( 115 mathrm{V} ) line. If line voltage
drops to ( 110 V ) line, the percentage drop in heat output will be:
A. ( 7.6 % )
B. ( 8.5 % )
c. ( 8.1 % )
D. 10.2 %
12
720In a Wheatstone bridge, three resistances ( P, Q ) and ( R ) are connected in the three arms and the fourth arm is
formed by two resistances ( S_{1} ) and ( S_{2} ) connected in parallel. The condition for the bridge to be balanced will be
A ( cdot frac{P}{Q}=frac{Rleft(S_{1}+S_{2}right)}{2 S_{1} S_{2}} )
в. ( frac{P}{Q}=frac{R}{S_{1}+S_{2}} )
c. ( frac{P}{Q}=frac{2 R}{S_{1}+S_{2}} )
D. ( frac{P}{Q}=frac{Rleft(S_{1}+S_{2}right)}{S_{1} S_{2}} )
12
721What is the relation between resistance
( mathrm{R} ) and resistivity ( rho ) of a wire ( ? )
A ( cdot R=frac{rho A}{l} )
в. ( R=frac{rho l}{A} )
c. ( R=frac{A}{rho l} )
D. ( _{R}=frac{l}{rho A} )
12
722In a meter bridge experiment, the ratio of the left gap resistance to right gap resistance is ( 2: 3, ) the balance point
from left is?
( mathbf{A} cdot 60 mathrm{cm} )
B. ( 50 mathrm{cm} )
c. ( 40 mathrm{cm} )
D. ( 20 mathrm{cm} )
12
723A non-zero current passes through the galvanometer F shown in the circuit
when the key ‘K’ is closed and its value
does not change when the key is opened. Then which of the following statement(s) is/are true?
This question has multiple correct options
A. The galvanometer resistance is infinite
B. The current through the galvanometer is ( 40 mathrm{mA} )
c. After the key is closed, the current through ( 200 Omega ) resistor is same as the current through the ( 300 Omega ) resistor
D. The galvanometer resistance is ( 150 Omega )
12
724The figure is a part of a closed circuit
Find the currents ( i_{1}, i_{2} ) and ( i_{3} )
12
725Ohm’s law can be applied to
A. ohmic devices
B. non-ohmic devices
( c . ) both (a) and (b)
D. none
12
726The dimensions of a rectangular
parallelepiped are ( 1 mathrm{cm} times 1 mathrm{cm} times )
( 100 mathrm{cm} . ) If its specific resistance is ( 3 x )
( 10^{-7} Omega m ) then the resistance between
its rectangular faces will be
A ( cdot 3 times 10^{-9} Omega )
В. ( 3 times 10^{-7} Omega )
c. ( 3 times 10^{-5} Omega )
D. ( 3 times 10^{-3} Omega )
12
727A resistance of ( 2 Omega ) is connected across
one gap of a metre-bridge (the length of the wire is ( 100 mathrm{cm} ) ) and an unknown
resistance, greater than ( 2 Omega ), is connected across the other gap. When these resistance are interchanged, the balance point shifts by ( 20 mathrm{cm} ) Neglecting any corrections, the unknown resistance is
A. ( 3 Omega )
в. ( 4 Omega )
( c cdot 5 Omega )
D. ( 6 Omega )
12
728The resistance of a wire at room
temperature ( 30^{circ} mathrm{C} ) is found to be ( 10 Omega )
Now to increase the resistance by ( 10 % ) the temperature of the wire must be:
[The temperature coefficient of resistance of the material of the wire is
( left.0.002 text { per }^{circ} Cright] )
A ( cdot 36^{circ} mathrm{C} )
в. ( 83^{circ} ) С
( mathbf{c} cdot 63^{circ} C )
D. ( 33^{circ} mathrm{C} )
12
729A potentiometer wire of length 10 m and resistance ( 30 Omega ) is connected in
series with a battery of emf ( 2.5 V ) internal resistance ( 5 Omega ), and an external
resistance ( boldsymbol{R} ). If the fall of potential
along the potentiometer wire is ( mathbf{5 0} mu V boldsymbol{m} boldsymbol{m}^{-1}, ) then the value of ( boldsymbol{R} ) is
found to be ( 23 n Omega ). What is ( n ? )
12
730What is the power produced by an appliance marked “240 V, 2 A”?
A. ( 8.3 mathrm{mw} )
B. 60 ( w )
c. ( 120 mathrm{w} )
D. ( 480 mathrm{w} )
12
731The electrical resistance of pure
platinum increases linearly with increasing temperature over a small range of temperature. This property is used in a Platinum resistance
thermometer. The relation between ( boldsymbol{R}_{boldsymbol{theta}} )
(Resistance at ( theta ) K) and ( R_{0} ) (Resistance
( left.operatorname{at} theta_{0} Kright) ) is given by ( R_{theta}=R_{0}[1+alpha(theta- )
( left.left.boldsymbol{theta}_{0}right)right], ) where ( boldsymbol{alpha}= ) temperature coefficient
of resistance. Now, if a Platinum
resistance thermometer reads ( 0^{circ} mathrm{C} )
when its resistance is ( 80 Omega ) and ( 100^{circ} mathrm{C} )
when its resistance is ( 90 Omega ), find the
temperature at which its resistance is
( 86 Omega )
12
732Assertion
If we bend an insulated conducting wire, the resistance of the wire
increases.
Reason
The drift velocity of electrons in bent
wire decreases.
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
733A copper wire carries a current of
density Assuming that one free electrone corresponding to each copper atom,evalute the distance which will be covered by an electrone during its displacement along the wire
12
734Two resistors of resistances ( boldsymbol{R}_{1}= )
( 100 pm 3 o h m ) and ( R_{1}=200 pm 4 o h m ) are
connected (a) in series, (b) in parallel. Find the equivalent resistance of the
(a) series combination,
(b) parellel
combination. Use for ( (a) ) the relation
( boldsymbol{R}=boldsymbol{R}_{1}+boldsymbol{R}_{2} ) and for ( (boldsymbol{b}) )
( frac{1}{R^{prime}}=frac{1}{R_{1}}+frac{1}{R_{2}} ) and ( frac{triangle R^{prime}}{R^{prime 2}}=frac{triangle R_{1}}{R_{1}^{2}}+ )
( frac{triangle boldsymbol{R}_{2}}{boldsymbol{R}_{2}^{2}} )
12
735The resistance of the platinum wire of a platinum resistance thermometer at the ice point is ( 5 Omega ) and at steam point
is ( 5.39 Omega . ) When the thermometer is
inserted in a hot bath, the resistance of
the platinum wire is ( 5.795 Omega . ) Calculate the temperature of the bath.
12
736Two resistors equal resisitances are joined in series and a current is passed through the combination. Neglect any
variation in resistance as the
temperature changes. In a given time interval
This question has multiple correct options
A. equal amounts of thermal energy must be produced in the resistors
B. unequal amount of thermal energy may be produced
c. the temperature must rise equally in the resistors
D. the temperature may rise equally in the resistors
12
737To balance the bridge in the circuit, the values of ( mathrm{R} ) is
( A cdot 8 Omega )
B. ( 4 Omega )
( c cdot 20 Omega )
D. ( 12 Omega )
12
738In a metre bridge, the balancing length from the left end (standard resistance
of one ohm is in the right gap) is found
to be ( 20 mathrm{cm} ). The value of the unknown
resistance is
A . ( 4 Omega )
B. ( 0.5 Omega )
c. ( 0.4 Omega )
D. ( 0.25 Omega )
12
739There are 5 tube-lights each of ( 40 W ) in a house. These are used on an average
for 5 hrs / day. In addition, there is an immersion heater of ( 1500 W ) used on
an average for 1 h ( / ) day. The number of
units of electricity that are
consumed in a month of 30 days is:
A. 25 units
B. 50 units
c. 75 units
D. 100 units
12
740( boldsymbol{n} ) identical cells, each of internal
resistance ( (r) ) are first connected in
parallel and then connected in series ( operatorname{across} ) a resistance ( (boldsymbol{R}) . ) If the
current through ( R ) is same in both the
cases then:
A. ( R=r / 2 )
в. ( r=R / 2 )
c. ( R=r )
( mathbf{D} cdot r=0 )
12
741The length of a potentiometer wire is ( 1200 mathrm{cm} ) and it carries a current of
( 60 m A . ) For cell of emf ( 5 V ) and internal
resistance of ( 20 Omega ), the null point on it is
found to be at ( 1000 mathrm{cm} . ) The resistance
of whole wire is:
A . ( 60 Omega )
в. ( 100 Omega )
( c .80 Omega )
D. ( 120 Omega )
12
742An electric current is the rate of flow of
electric charges and it is measured in Ampere.
A. True
B. False
12
743According to Ohm’s law the graph of potential difference and current is
A. Straight line passing through origin
B. Curved
c. Line having an intercept on ( x ) -axis
D. Circular
12
744The resistance between ( A ) and ( B ) in the
given figure will be(in ohm):
A. 20
B. 30
c. 90
D. more than 10 but less than 20
12
745The potential difference across the ends of a resistor is ( _{-}-_{-}-_{-}-_{-}- ) to the
current through it
A. directly proportional
B. inversely proportional
c. square proportional
D. none of these
12
746Assertion : Current is passed through a metallic wire, heating it red. When cold water is poured on half of it, the rest
becomes more hot.

Reason: Resistance decreases due to
the decrease in temperature and then
current through wire increases.
A. Both (A) and (R) are true and (R) is the correct explanation of A
B. Both (A) and (R) are true but (R) is not the correct explanation of A
c. (A) is true but (R) is false
D. (A) is false but (R) is true

12
747An electric toaster draws ( 8 A ) current in
a ( 220 V ) circuit. It is used for ( 2 h r . ) What
is the cost of operating the toaster if the
( operatorname{cost} ) of electrical energy is
Rs. ( 4.5 / k W h ? )
A. ( R s .9 .50 )
B. Rs. 25.50
c. ( R s .14 .84 )
D. Rs. 15.84
12
748State Ampere’s circuital law.12
749When a resistor of ( 11 Omega ) is connected in
series with a electric cell. The current
following in it is ( 0.5 A . ) Instead when a resistor of ( 5 Omega ) is connected to the same
electric cell in series, the current increases by ( 0.4 A . ) The internal resistance of the cell is
A. ( 1.5 Omega )
B. 2Omega
( c .2 .5 Omega )
D. 3.5Omega
12
750Mobility of free electrons in a conductor
¡s:
A. directly proportional to electron density
B. directly proportional to relaxation time
C. inversely proportional to electron density
D. inversely proportional to relaxation time
12
751Two cells of same emf are connected in
series. Their internal resistances are ( r_{1} )
and ( r_{2} ) respectively and ( r_{1}>r_{2} . ) When
this combination is connected to an
external resistance ( R ) then the potential difference between the terminals of first
cell becomes zero. In this condition the
value of R will bw
A ( cdot frac{r_{1}-r_{2}}{2} )
B. ( frac{r_{1}+r_{2}}{2} )
c. ( r_{1}-r_{2} )
D. ( r_{1}+r_{2} )
12
752Two conductors ( A ) and ( B ) of the same
length and diameter are connected across the same battery. The resistivity of ( A ) is twice that of ( B ). If
( P_{A} ) and ( P_{B} ) be the powers dissipated
( operatorname{across} A ) and ( B, ) respectively, then
A ( cdot P_{A}=P_{B} )
В. ( P_{A}>P_{B} )
c. ( P_{A}<P_{B} )
D. ( P_{A}=P_{B}=1 )
12
753A wire ( 50 mathrm{cm} ) long and ( 1 mathrm{mm}^{2} ) in cross
section carries a current of 4 A when
connected to a 2 V battery. The resistivity of the wire is
A. ( 2 times 10^{-7} Omega m )
В. ( 5 times 10^{-7} Omega m )
c. ( 4 times 10^{-6} Omega m )
D. ( 1 times 10^{-6} Omega m )
12
754There is a current of 40 amperes in a
wire of ( 10^{-16} m^{2} ) area of cross-section. If
the number of free electrons per ( m^{3} ) is
( 10^{29}, ) then the drift velocity will be:
A ( cdot 1.25 times 10^{3} mathrm{m} / mathrm{s} )
в. ( 2.50 times 10^{3} ) т/ ( s )
c. ( 2.0 times 10^{6} mathrm{m} / mathrm{s} )
D. ( 25 times 10^{6} mathrm{m} / mathrm{s} )
12
755One ampere equals
A ( cdot 10^{6} mu A )
В ( cdot 10^{-6} mu A )
( mathbf{c} cdot 10^{-3} mu A )
D. 10 A
12
756The graph represent a current-voltage behaviour of a water-voltameter. spot
the correct explanation.
A. Dissociation takes place at ( E_{1} ) and it obeys Ohm’s law
thereafter.
B. Ohm’s law is not valid for low voltages
C. Ohm’s law is obyed but only for potential difference larger than back emf.
D. Electrolyte does not obey Ohm’s law.
12
757A metal wire of resistivity ( 64 times 10^{-6} Omega )
and length ( 198 mathrm{cm} ) has a resistance of 7
12
758In the given in each the current in
each resistance is:
A. ( 0 A )
B. ( 1 A )
c. ( 0.25 A )
D. ( 0.5 A )
12
759A cell drives a current through a circuit
The e.m.f. of the cell is equal to the work done in moving unit charge:
This question has multiple correct options
A. from the positive to negative plate of the cell
B. from the positive plate back to the positive plate
C. from the negative plate back to the negative plate
D. from any point in the circuit back to the same point
12
760Resistance of a platinum resistance thermom-eter is 2 ohm at ( 20^{circ} mathrm{C}, 4 ) ohm
at ( 100^{circ} C ) and 2.2 ohm at some
temperature. this temperature-is
A ( cdot 20^{circ} mathrm{C} )
B. 30
( mathbf{c} cdot 40^{circ} mathrm{C} )
D. ( 28^{circ} mathrm{C} )
12
761Three ( 60 mathrm{W} ), 120 ( mathrm{V} ) light bulbs are
connected across a ( 120 mathrm{V} ) power line as
shown in Fig. Find the voltage across
each bulb.
12
762Suppose a current carrying wire has a
become smaller along the wire has the
shape of a very long cone as shown in figure.Then:
This question has multiple correct options
A. electric current is different in different portions of wire
B. electric current is same everywhere.
C. drift speed of electrons at point ( A ) is lesser than that of at point B.
D. drift speed of electrons at point ( A ) is same as that of at point B.
12
763An energy source will supply a constant
current into the load if its internal
resistance is
A. zero
B. nonzero but less than the resistance of the loadd
c. equal to the resistance of the loadd
D. very large as compared to the load resistance
12
764You have three resistors of values
( 2 Omega, 3 Omega, ) and ( 5 Omega . ) If they are in parallel then the total resistance is :
( mathbf{A} cdot 0.97 Omega )
в. ( 2 Omega )
( c .10 Omega )
D. 3.
12
765The graph of two conductors of same
materials connected in series justify (i)
which one has more resistance
(ii)Which one will produce more heat?
12
766The circuit shown in Figure contains
three resistors ( boldsymbol{R}_{1}=mathbf{1 0 0} boldsymbol{Omega}, boldsymbol{R}_{2}=mathbf{5 0} boldsymbol{Omega} )
and ( R_{3}=20 Omega ) and cells of emfs ( E_{1}= )
( 2 V ) and ( E_{2} . ) The ammeter indicates a
current of 50 mA. Determine the
currents in the resistors and the emf of
the second cell. The internal resistance
of the ammeter and of the cells should
be neglected
12
767A cell of negligible resistance and emf 2 volt is connected to a series
combination of 2,3 and 5 ohm. The
potential difference in volts between the terminals of 3 -ohm resistance will be:
A. ( 0.6 v o l t )
B. ( frac{2}{3} ) volt
c. ( 3 v o l t s )
D. ( 6 v o l t s )
12
768( fleft(x_{A}=2 V ) calculate current flowing right.
through the circuit and calculate ( V_{B} )
and ( V_{C} ? )
12
769The temperature co-efficient of
resistance of a wire is ( 0.0012 /^{circ} mathrm{C} ). Its
resistance is ( 1 Omega ) at ( 300 K . ) At what
temperature, its resistance will be ( 2 Omega ? )
A . ( 1133 K )
B. ( 854 K )
c. ( 1217 K )
D. ( 1154 K )
12
770Assertion
Drift velocity of electrons is
independent of time.
Reason
Electrons are accelerated in the
presence 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
77136 identical cell each having emf 1.5 volt
and internal resistance ( 0.5 Omega ) are
connected in series with an external
resistance of ( 12 Omega ). If 6 cells are wrongly connected then current through the circuit will be
A ( cdot 1.2 mathrm{A} )
B. 1 A
( c cdot 2 A )
D. 4 A
12
772The North pole of a magnet is brought near a negatively charged conductor.
A. Force acting on the pole will be zero
B. Force acting on the pole will be maximum.
c. Force acting on the pole will be minimum.
D. none
12
773Four conductors of resistance 4,3,9
and 6 ohm are connected in ( A B, B C, C D ) and DA arms of a Wheatstone bridge. The bridge can be balanced by connecting.
A. ( 1) 6 ) ohm in series with 3 ohm conductor
B. 2) 4 ohm in parallel with 6 ohm conductor
c. 3 ) 3 ohm in series with 3 ohm conductor
D. 4 ) 5 ohm in series with 6 ohm conductor
12
774With the help of a neatly drawn and
labelled diagram, obtain balancing
condition of a Wheatstone bridge.
12
775Two electric charges ( 12 mu C ) and ( -6 mu )
electric field intensity at zero potentia
and outside the region between them
A ( cdot 1.25 times 10^{6} N / C )
В. ( 3.75 times 10^{5} N / C )
c. ( 4.5 times 10^{6} N / C )
D. ( 6.75 times 10^{5} N+C )
12
776What is the power produced by an appliance marked ” ( 240 V, 2 A ? )
A. ( 8.3 m W )
в. ( 60 W )
c. ( 120 W )
D. ( 480 W )
12
777Which of the following is not true for
wire wound resistor?
A. It has a lower order of stability and reliability.
B. It has high power rating with a low tolerance value.
C. Easy to make wire wound resistor of value 0.01 Ohm.
D. It is not suitable for high-frequency circuits.
12
778The temperature coefficient of a wire is ( 0.00125^{0} C^{-1} . ) At ( 300 mathrm{K} ) its resistance is
one ohm.The resistance of the wire will
be ( 2 Omega ) at
( mathbf{A} cdot ) 1154 ( mathbf{K} )
B. ( 1100 mathrm{k} )
( c cdot 1400 k )
D. 1127 K
12
779Why can one ignore quantisation of electric charge when dealing with macroscopic i.e., large scale charges?12
780The slope of current (I) versus voltage
(V) is called:
A . resistance
B. resistivity
c. conductivity
D. conductance
12
781No two equipotential surface intersect each other ?why?12
782Electric current is due to flow of charge
carriers in the conductors. Which of the
following is/are correct?
This question has multiple correct options
A. The drift speed of charge carriers is a very small fraction of the mean thermal agitation speed of the same charge carriers
B. The number of charge carriers per unit volume is always the same as the number of atoms of the conductor per unit volume
C. The drift velocity is proportional to the electric field applied ordinarily
D. In an intrinsic semiconductor, the charge carriers are either electrons only or holes only; both of them may not participate in conduction
12
783An ideal cell having a steady emf of
2 volts is connected across the
potentiometer wire of length ( 10 m ). The
potentiometer wire is of magnesium and having resistance of ( 11.5 Omega / m . ) An another cell gives a null point at ( 6.9 m ). If
a resistance of ( 5 Omega ) is put in series with potentiometer wire, the new position of the null point is given as ( frac{x}{10} m . ) Find ( x )
12
784Two resistances ( R_{1} ) and ( R_{2} ) are made of
different materials. The temperature
coefficient of the material of ( boldsymbol{R}_{1} ) is ( boldsymbol{alpha} )
and that of material of ( boldsymbol{R}_{2} ) is ( -boldsymbol{beta} ). The
material of ( boldsymbol{R}_{1} ) and ( boldsymbol{R}_{2} ) will not change with temperature if ( frac{boldsymbol{R}_{1}}{boldsymbol{R}_{2}} ) equal to
( mathbf{A} cdot frac{alpha}{beta} )
В. ( frac{alpha+beta}{alpha-beta} )
c. ( frac{alpha^{2}+beta^{2}}{2 alpha beta} )
D. ( frac{beta}{alpha} )
12
785Estimate the average drift speed of
conduction electrons in a copper wire of
cross-sectional area ( 1.0 times 10^{-7} m^{2} )
carrying a current of 1.5 A. Assume the
density of conduction electrons to be
( 9 times 10^{28} m^{-3} )
12
786The wire loop PQRSP formed by joining
two semi-circular wires of radii ( boldsymbol{R}_{1} ) and
( R_{2} ) carries a current I as shown. The
magnitude of the magnetic induction at
the centre ( C ) is
A ( cdot frac{mu_{0} I}{4} frac{R_{2}-R_{1}}{R_{2}} )
В ( cdot frac{mu_{0} I}{4} frac{R_{2}-R_{1}}{R_{1}} )
C ( cdot frac{mu_{0} I}{4} frac{R_{2}-R_{1}}{R_{2} R_{1}} )
D. None of these
12
787A long wire carrying a current ( i ) is bent
to form a plane angle ( alpha ). Find the
magnetic field ( B ) at point on the
bisector of this angle situated at a distance ( x ) from the vertex
12
788In the circuit shown here, ( boldsymbol{E}_{mathbf{1}}=boldsymbol{E}_{2}= )
( boldsymbol{E}_{3}=2 boldsymbol{V} ) and ( boldsymbol{R}_{1}=boldsymbol{R}_{2}=boldsymbol{4} ) ohms. The
current flowing between points ( A ) and ( B )
through battery ( boldsymbol{E}_{2} ) is :-
A . zero
B. 2 amp from A to B
c. 2 amp from ( B ) to ( A )
D. none of the above
12
789A battery of ( boldsymbol{E} boldsymbol{M} boldsymbol{F} ) 3 ( boldsymbol{v} ) and internal
resistance ( r ) connected in series with
the resistor ( 55 Omega ) through can ammeter
of resistance ( 1 Omega ) it reads ( 50 m A )
Calculate ( r )
12
790The resistances of the four arms ( P, Q, R ) and ( sin ) a Wheatstone’s bridge are 10
ohm, 30 ohm, 30 ohm and 90 ohm, respectively. The e.m.f. and internal resistance of the cell are 7 volt and 5 ohm respectively. If the galvanometer
resistance is 50 ohm, the current drawn
from the cell will be
A . ( 1.0 mathrm{A} )
B. 0.2 A
( c cdot 0.1 mathrm{A} )
D. 2.0 A
12
791For electrolytes, Ohm’s Law may be written as:
A ( cdot frac{V}{I}=R )
B. ( frac{V+V_{b a c k}}{I}=R )
c. ( frac{V-V_{b a c k}}{I}=R )
D. ( frac{V_{b a c k-V}}{I}=R )
12
792Assertion
The wire of a potentiometer should be of uniform area of cross section.
Reason
It satisfies the requirement of the
principle of the potentiometer.
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
793The resistance of all the wire between
any two adjacent dots is ( R ). The
equivalent resistance between ( A ) and ( B )
as shown is
A . ( 7 R / 13 )
B. ( 7 R / 6 )
c. ( 14 R / 8 )
D. ( 15 R / 7 )
12
794According to kircholf’s second law:12
795If ( 400 Omega ) of resistance is made by adding four ( 100 Omega ) resistance of tolerance ( 5 % )
then the tolerance of the combination
is?
A . ( 15 % )
B. 20%
c. ( 5 % )
D. ( 10 % )
12
796Twelve identical resistors of ( 6 Omega )
each are connected to form a cube as
shown above. The effective resistance
across the solid diagonal, AG is :
( A .5 Omega )
B. ( 4.5 Omega )
( c .3 .5 Omega )
( mathbf{D} cdot 1.5 Omega )
12
797( boldsymbol{V}-boldsymbol{I} ) graph for two wires ( boldsymbol{A} ) and ( boldsymbol{B} ) are
shown in the figure. If the both wires are of same length and same thickness,
which of the two is made of a material
of high resistivity? Given justification
12
798A nichrome wire ( 1 mathrm{m} ) long and ( 1 mathrm{mm}^{2} ) in
crosssectional area draws 4 ampere at
2 volt. The resistivity of nichrome is
A ( cdot 1 times 10^{-7} n m )
В. ( 2 times 10^{-7} n m )
c. ( 4 times 10^{-7} n m )
D. ( 5 times 10^{-7} n m )
12
799An inductor of 2 henry and a resistance of 10 ohms are connected in series with
a battery of 5 volts. The initial rate of
change of current is:
A. 0.5 amp/sec
B. 2.0 amp/sec
c. 2.5 amp/sec
D. 0.25 amp / sec
12
800The reading of poteniometer if ( 4 V )
battery is used instead of ( e ), is
A ( .88 .3 mathrm{cm} )
в. ( 47.3 mathrm{cm} )
( mathrm{c} .95 mathrm{cm} )
D. cannot be calculated
12
801A simple circuit consisting of three
resistors is shown above. ( boldsymbol{R}_{1} ) has the
same resistance of ( boldsymbol{R}_{2} ) and ( boldsymbol{R}_{2} ) has twice
the resistance of ( boldsymbol{R}_{3} ). If the switch
remains closed, determine the ratio of
heat dissipated of ( boldsymbol{R}_{1} ) to ( boldsymbol{R}_{2} )
( mathbf{A} cdot 1: 9 )
B. 1: 3
c. 1:
D. 3:
E. 9: 1
12
802toppr ( L )
potentiometer and measures the corresponding current in the circuit.
The table of data and the resistance vs.
current graph created by the student is shown below.
Based on the experimental data collected by the student, determine the
emf of the battery.
B. 0.5
c. 1.0
D. 2.0
E. 3.0
12
803( A 1^{circ} C ) rise in temperature is observed in a conductor by passing a certain current. If the current is doubled, then
the rise in temperature is approximately
( mathbf{A} cdot 2.5^{circ} mathrm{C} )
B . ( 4^{circ} mathrm{C} )
( mathrm{c} cdot 2^{circ} mathrm{C} )
D. ( 1^{circ} mathrm{C} )
12
804Electrical power ( P ) is given by expression : ( boldsymbol{V} times boldsymbol{x} . ) What is ( boldsymbol{x} ) ?
A. Charge
B. current
c. Resistance
D. None of these
12
805Consider a long conductor, the middle of
which is earthed. If the potential
difference across the two ends of the
conductor is ( 220 mathrm{V} ), then what is the
potential at the ends and the middle
point?
A. ( 220 V ) all over the conductor
B. ( 110 V ) and ( -110 V ) at ends and ( 0 V ) at the mid point
C. ( 0 V ) at ends and ( 220 V ) at midpoint
D. ( -220 mathrm{V} ) all over the conductor
12
806In the 5 band color resistor,which color
bands are considered as significant
digits?
A. First band only
B. First three bands
c. First two bands
D. Last band
12
807( cdotleft[begin{array}{l}1 \ 1end{array}right]_{1}^{1}, quad )
( a_{-1 / 1}^{11}[1]_{1} )
( therefore sum_{i=1}^{infty} z_{k} )
12
808The mass of a wire of resistance 20 ohm
is 50 gram. The resistance of the same
wire of mass 10 gram is
A . ( 4 Omega )
B. 5Omega
( c cdot 100 Omega )
D. 80Omega
12
809In an experiment of Wheatstone bridge,
if the positions of cells and
galvanometer are interchanged, then the balance points will
A. change
B. remain unchanged
c. depend on the internal resistance of the cell and resistance of the galvanometer
D. none of these
12
810Two wires of resistance ( boldsymbol{R}_{1} ) and ( boldsymbol{R}_{2} ) at
( 0^{circ} C ) have temperature coefficient of
resistance ( alpha_{1} ) and ( alpha_{2}, ) respectively. These are joined in series. The effective temperature coefficient of resistance is
:-
A ( cdot frac{alpha_{1}+alpha_{2}}{2} )
в. ( sqrt{alpha_{1} alpha_{2}} )
c. ( frac{alpha_{1} R_{1}+alpha_{2} R_{2}}{R_{1}+R_{2}} )
D. ( frac{sqrt{R_{2} R_{1} alpha_{1} alpha_{2}}}{sqrt{R_{1}^{2}+R_{2}^{2}}} )
12
811An electric iron is connected to a ( 200 V )
mains supply and draws a current of ( 4.0 A ) What is the power rating of the iron?
( mathbf{A} cdot 800 W )
в. ( 50 W )
c. ( 106 W )
D. ( 112 W )
12
812Which resistor is difficult to make of
having a value less than about 2 Ohms?
A. Iron Resistor
B. Carbon Resistor
c. Wire wound Resistor
D. Both b and c
12
and of fixed emf, the resistor ( boldsymbol{R}_{1} ) has
fixed resistance and the resistance of
resistor ( boldsymbol{R}_{2} ) can be varied (but ( boldsymbol{R}_{2} ) is
always nonzero). Then the electric power
delivered to the resistor of resistance
( R_{1} ) is independent of the value of
resistance ( boldsymbol{R}_{2} )
Reason
f potential difference across a fixed
resistance is unchanged, the power delivered to the resistor remains
constant.
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
814State whether true or false:
Good conductors have excess of free
electrons.
A. True
B. False
12
815A student connects four cells, each of internal resistance ( frac{1}{4} Omega, ) in series. One of the cells is incorrectly connected because its terminals are reversed. The
value of external resistance is ( 1 Omega . ) If the
emf of each cell is 1.5 volt then current
in the circuit will be
A ( cdot frac{4}{3} A )
B. 0
c. ( frac{3}{4} )
D. ( 1.5 A )
12
816How many electrons flow through a wire,
when 1 A current passes for a millisecond?
12
817What is mean by drift velocity?
current of 0.5 ampere flows in a wire of
radius ( 0.5 m m . ) If the number of free
electrons in the wire be ( 4 times 10^{28} ) per ( m^{3} )
calculate their drift velocity.
12
818Six equal capacitors each of
capacitance ( C ) are connected as shown
in the figure. The equivalent
capacitance between points ( A ) and ( B ) is :
A ( .1 .5 mathrm{c} )
( B )
( c cdot 2 c )
D. ( 0.5 mathrm{c} )
12
819Two long straight cylindrical conductors
with resistivities ( rho_{1} ) and ( rho_{2} ) respectively
are joined together as shown in figure. If current I flows through the conductors, the magnitude of the total free charge at the interface of the two conductors is
A . zero
в. ( frac{left(rho_{1}-rho_{2}right) I varepsilon_{0}}{2} )
( mathbf{c} cdot varepsilon_{0} Ileft|rho_{1}-rhoright| )
( mathbf{D} cdot varepsilon_{0} Ileft|rho_{1}+rhoright| )
12
820Two resistors are connected a) in series
b) in parallel. The equivalent resistance in two cases are 9 ohm and 2 ohm respectively. Then the resistance of the component
resistors are.
A. 2 ohm and 7 ohm
B. 3 ohm and 6 ohm
c. 3 ohm and 9 ohm
D. 5 ohm and 4 ohm
12
821Five conducting parallel plates having
area ( A ) and separation between them ( d )
are placed as shown in the figure. Plate number 2 and 4 are connected with wire
and between ( A ) and ( B, ) a cell of emf ( E ) is
connected. Find the charge flown
through the cell.
12
822( 1 m A= )
( mathbf{A} cdot 1000 A )
B. ( 10^{-3} A )
( mathbf{c} cdot 1 C s^{-1} )
D. None
12
823The equivalent resistance between ( A )
and B is:
A ( frac{8 R}{5} )
в. ( frac{5 R}{8} )
( c cdot frac{3 R}{8} )
D. ( frac{7 R}{8} )
12
824In the circuit shown, the value of
currents ( I_{1}, I_{2} ) and ( I_{3} ) are
‘ 3 A, ( frac{-3}{2} A, frac{9}{2} ),
3. ( frac{9}{2} A, 3 ) A, ( frac{-3}{2} ) A
c. ( 5 A, 4 A,-3 ) f
( 7 A, frac{5}{4} A, frac{9}{2} A )
12
825The expression of electric power ( (boldsymbol{P})= )
A ( cdot I R^{2} )
в. ( V I )
c. ( I R )
D. ( V R^{2} )
12
826If a wire is stretched to make its length three times, its resistance will become
A. Three times
B. One-third
c. Nine times
D. One-ninth
12
827In the shown arrangement of the
experiment of the meter bridge if ( boldsymbol{A C} )
corresponding to null deflection of
galvanometer is ( x, ) what would be its
value if the radius of the wire ( A B ) is
doubled?
( A )
B. ( x / 4 )
( c cdot 4 x )
D. ( 2 x )
12
828For the circuit shown, with ( boldsymbol{R}_{1}= )
( mathbf{1 . 0 Omega}, boldsymbol{R}_{mathbf{2}}=mathbf{2 . 0 Omega}, boldsymbol{E}_{mathbf{1}}=mathbf{2} boldsymbol{V} ) and ( boldsymbol{E}_{mathbf{2}}= )
( E_{3}=4 V, ) the potential difference
between the points ( ^{prime} a^{prime} ) and ( ^{prime} b^{prime} ) is
approximately (in ( V ) )
( A cdot 2.7 )
в. 3.3
( c .2 . )
3.3 .3
12
829Three ( 100 W, 150 V ) lamps are
connected across ( 150 V ) line.Find
voltage across each and power
disseminate in 3 bulbs.
12
830In general, the resistance to electric
current of a material; in particular, the degree to which a material resists the flow of electricity is called
A. conductivity
B. resistivity
c. conductance
D. none of the above
12
831Which pair is not correct for the
instrument used in the laboratory and
their uses from the following?
Instrument uses
To measure the electric
( begin{array}{ll}text { (A) } & text { Voltmeter }end{array} quad ) potential difference
To measure the electric
To detect the presence
(C) Galvanometer of current
To supply the electric
( A cdot A )
B. B
( c cdot c )
( D cdot D )
12
832When two unknown resistances are
placed in the gaps of meterbridge, the null point is found to be ( 40 mathrm{cm} ) from one
end of the bridge wire. When one of the
resistances is shunted with a 10
ohm coil, the null point is ( 25 mathrm{cm} ) from the same end. The value of each of the
unknown resistances is
( mathbf{A} cdot 15 Omega, 10 Omega )
в. ( 10 Omega, 15 Omega )
( mathbf{c} cdot 20 Omega, 30 Omega )
D. ( 30 Omega, 20 Omega )
12
833The power of the heater is ( 1000 W ) at
( 1000^{circ} mathrm{C} . ) What will be its power at
( 4000^{circ} mathrm{C} ? )
Given, temperature coefficient of resistance of heater-wire is ( 1.4 times )
( 10^{-40} C^{-1} )
A ( .1 .42 times 10^{3} W )
в. ( 1.3 times 10^{3} mathrm{W} )
c. ( 9.68 times 10^{3} W )
D . ( 1.08 times 10^{3} W )
12
834Define mobility. Give its unit.12
835The product of resistivity and conductivity of a cylindrical conductor depends on
A. Temperature
B. Material
c. Area of cross-section
D. None of the above
12
836What should be the characteristic of
fuse wire?
A. High melting point, high specific resistance
B. Low melting point, low specific resistance
C. High melting point, low specific resistance
D. Low melting point, high specific resistance
12
837Draw. Wheatstone’s bridge circuit and write the condition for its balance.12
838The length of potentiometer wire is ( 10 mathrm{m} ) and is connected in series with an
accumulator. The e.m.f. of a cell balances against ( 250 mathrm{cm} ) length of wire. If the length of potentiometer wire is increased by ( 1 mathrm{m} ), calculate the new balancing length of wire.
12
839Electromotive force of a cell is basically
( mathbf{a} )
( A cdot ) force
B. power
c. work
D. current capacity
12
840A potentiometer wire of length ( 1 m ) has a
resistance of ( 10 Omega ). It is connected to a
( 6 V ) battery in series with a resistance of
5. Determine the emf of the primary cell which gives a balance point at
( 40 mathrm{cm} )
12
841If the switch at point ( P ) is opened
(shown in the figure) choose the correct
option
A. the current in ( R_{1} ) would not change
B. the potential difference between point ( X ) and the ground would increas
c. the current provided by the battery would increase
D. the emf produced by the battery (assumed to have internal resistance) would change
12
842The quantity of charge flowing per unit time is called
A . capacitance.
B. charge density.
c. current
D. potential difference
12
843If the current through a resistor in a circuit increases by ( 3 %, ) the power dissipated by the resistor
A. Increases approximately by 3%.
B. Increases approximately by 6%.
c. Increases approximately by ( 9 % )
D. Decreases approximately by 3%
12
844A uniform wire of resistance ( 1 Omega m^{-1} ) is
bent into a circle of radius 1 m. The
same wire is connected across a
diameter ( A B ) as shown in the figure.
The effective resistance between ( A ) and
( boldsymbol{B} ) is:
( A )
B. ( frac{2 pi}{pi+2} Omega )
c. ( frac{pi+4}{2 pi} Omega )
D. ( frac{2 pi}{pi+4} Omega )
12
845The relation, between current density
and drift velocity ( v_{d} ) is?
A ( . j=n e v_{d} )
B. ( j=frac{n e}{v_{d}} )
C. ( j=frac{v_{d} e}{n} )
D. ( j=n e v_{d}^{2} )
12
846An electric iron is connected to the 230
V mains supply. A current of 8 A flows through the iron. How much energy is transferred to the heater each second?
A . ( 1640 J )
B. 1840J
c. ( 1750 J )
D. 980J
12
847Effective capacitance between ( A ) and ( B )
in the figure shown is (all capacitances
( operatorname{are} operatorname{in} mu boldsymbol{F}) )
( ^{A} cdot frac{3}{14} mu F )
в. ( frac{14}{3} mu F )
( c cdot 21 mu F )
D. ( 23 mu F )
12
848An accumulator of emf 2 Volt and
negligible internal resistance is connected across a uniform wire of
length ( 10 mathrm{m} ) and resistance ( 30 Omega ). The
appropriate terminals of a cell of emf
( 1.5 V o l t ) and internal resistance ( 1 Omega ) is
connected to one end of the wire, and
the other terminal of the cell is
connected through a sensitive galvanometer to a slider on the wire. If the balancing change when the cell of
1.5 volt is shunted with a resistance of ( 5 Omega ) is ( frac{x}{4} m . ) Find ( x )
12
849Find the relation between drift velocity
and relaxation time of charge carriers in a conductor. A conductor of length ( boldsymbol{L} )
is connected to a d.c. The source of emf
( E^{prime} . ) If the length of the conductor is
tripled by stretching it, keeping ( ^{prime} boldsymbol{E}^{prime} ) constant, explain how its drift velocity would be affected.
12
850In the circuit shown, the current in the
1 ( Omega ) resistor is
( mathbf{A} cdot 1.3 A, ) from ( P ) to ( Q )
B. ( 0 A )
c. ( 0.13 A ), from ( Q ) to ( P )
( 0.13 A, ) from ( P ) to ( Q )
12
851The belt of an electrostatic generator is ( 50 mathrm{cm} ) wide and travels at ( 30 mathrm{cm} / mathrm{sec} )
The belt carries into the sphere at a rate
corresponding to ( 10^{-4} ) ampere. What is the surface density of charge on the belt.
A ( cdot 6.7 times 10^{-5} mathrm{Am}^{-2} )
В. ( 6.7 times 10^{-4} mathrm{Am}^{-2} )
c. ( 6.7 times 10^{-7} mathrm{Am}^{-2} )
D. ( 6.7 times 10^{-8} mathrm{Am}^{-2} )
12
852In a parallel circuit of bulbs,
A. same current exists in all the bulbs
B. voltage across each bulb remains the same
C. failure of any bulb leads to a break in the circuit
D. all the above
12
853By increasing the temperature, the specific resistance of a conductor and a
semiconductor.
A. Increasing for both
B. Decreases for both
c. Increases, decreases
D. Decreases, increases
12
854e.m.f. is measured in
A. Joules
B. ( frac{text { Joules }}{text { coulomb }} )
c. Joule-coulombs
D. coulomb
12
855Write Kirchhoff’s first rule. A battery of
( mathbf{1 0} boldsymbol{V} ) and negligible internal resistance is connected to the diagonally opposite corners of a cubical network consisting
of 12 resistors each of resistance ( 2 Omega )
Determine the equivalent resistance of the network.
12
856In a balanced wheat stone bridge,
current in the galvanometer is zero. It
remains zero when
( [1] . ) battery emf is increased
( [2] . ) all resistances are increased by 10 ohms
( [3] . ) all resistances are made five times
( [4] . ) the battery and the galvanometer are interchanged
A . only [1] is correct
B. [1],[2] and [3] are correct
c. [1],[3] and [4] are correct
D. [1] and [3] are correct
12
857For driving current of ( 2 A ) for 6 minute in a circuit. ( 1000 J ) of work is to be done.
The e.m.f. of the source in the circuit is
A . ( 1.38 V )
в. ( 1.68 V )
c. ( 2.03 V )
D. 3.10V
12
858in a meter bridge, the balance point is found to be ( 40 mathrm{cm} ) from one end (say end
A). if a resistance of ( 10 Omega ) is connected
in series with ( R, ) a balance point is
obtained ( 60 mathrm{cm} ) from end
A. What are
the values of ( R ) and ( S(S ) is other resistance in series with ( boldsymbol{R} ) )?
12
859If current in a source of e.m.f. is in the
direction of e.m.f., the energy of the
source
A. Increase
B. Decrease
c. Remains constant
D. zero
12
860The total current supplied to the circuit
by the battery is
( mathbf{A} cdot 1 mathbf{A} )
B. 2 A
( c cdot 4 A )
( D cdot 6 A )
12
861Kirchoff’s junction law is equivalent to
A. Conservation of energy
B. conservation of charge
c. conservation of electric potential
D. Conservation of electric flux
12
862A cell of emf ( E ) is connected across a
resistance ( R ). The potential difference
across the terminals of the cell is ( V )
What is the internal resistance of the
cell?
A ( cdot E-frac{V}{R} )
в. ( frac{E-V}{V} )
c. ( frac{E-V}{R} times V )
D. ( frac{E-V}{V} times R )
12
863In the circuit shown in the figure the
heat produced in the 5 ohm resistor due
to the current flowing through it is 10
calories per second. The heat generated
in the 4 ohm resistor is
A. 1 calorie ( / )per
B. 2 calorie/sec
c. 3 calorie ( / )per
D. 4 calorie / per
12
864Figure below shows a portion of an
electric circuit with the currents in
amperes and their directions. The
magnitude and direction of the current
in the portion ( P Q ) is
( mathbf{A} cdot 0 A )
B. ( 3 A ) from ( P ) to ( Q )
c. ( 4 A ) from ( Q ) to ( P )
D. ( 6 A ) from ( Q ) to ( P )
12
865The electrical energy in kilowatt hours consumed in operating ten ( 50 ~ W )
bulbs for 10 hrs/day in a month of
30 days is
A. 1500
B. 15000
c. 15
D. 150
12
866Three equal resistors are connected as
shown in figure. the maximum power
consumed by each resistor is 18 W. Then the maximum power consumed by the combination is :
A. ( 18 W )
в. ( 27 W )
( c .36 W )
D. ( 54 W )
12
867A battery of 20 cells (each having e.m.f. 1.8 volt and internal resistance 0.1 ohm
is charged by 220 volts and the charging current is 15 A. The resistance to be put in the circuit is
A . 10.27 ohms
B. 12.27 ohms
c. 8.62 ohms
D. 16.24 ohms
12
868In the circuit shown in the figure, ammeter and voltmeter are ideal. If
( E=4 V ) and ( R=15 Omega ) and ( r=1 Omega, ) then
the reading of the ammeter is
A ( cdot frac{1}{3} A )
( B cdot frac{2}{3} A )
( c cdot 1 A )
D. ( frac{1}{4} A )
12
869A battery of emf ( 15 mathrm{V} ) and internal resistance of ( 4 Omega ) is connected to a
resistor. If the current in the circuit is 2
A and the circuit is closed. Resistance
of the resistor and terminal voltage of the battery will be.
A ( .2 .5 Omega, 6 vee )
B. ( 3.5 Omega, 6 v )
c. ( 2.5 Omega, 7 v )
D. ( 3.5 Omega, 7 vee )
12
870A heater coil operates at ( 1200 v ) when
connected to a ( 240 W ) supply.The
resistivity and area of across section of the coil are :
A ( cdot A=frac{rho l}{7000} )
в. ( A=frac{rho l}{8000} )
c. ( _{A}=frac{rho l}{6000} )
D. ( _{A}=frac{rho l}{600} )
12
871In the adjoining diagram ( boldsymbol{R}_{1}= ) ( mathbf{1 0 Omega}, boldsymbol{R}_{2}=mathbf{2 0 Omega}, boldsymbol{R}_{3}=mathbf{4 0 Omega}, boldsymbol{R}_{4}=mathbf{8 0 Omega} )
and ( V_{A}=5 V, V_{B}=10 V, V_{C}= )
( 20 V, V_{D}=15 V . ) The current in the
resistance ( boldsymbol{R}_{1} ) will be
A. 0.4 A towards 0
B. 0.4 A away from 0
( c . ) 0.6 A towards 0
D. 0.6 A away from 0
12
872Which of the following does not belong to the group formed by the others?
A. Iron
B. Tin
c. Glass
D. stee
12
873Two resistances of ( 400 Omega ) and ( 800 Omega ) are
connected in series with a 6 volt battery of negligible internal resistance. A
voltmeter of resistance ( 10,000 Omega ) is used to measure the potential difference across ( 400 Omega ). The error in the
measurement of the potential difference in volts approximately is :
A . 0.01
B. 0.02
( c .0 .03 )
D. 0.05
12
874Two wires of the same material and
length have radii in the ratio of 2: 3
Compare their resistance.
12
875A wire of resistance ( 40 Omega ) is bent into a
square. Then consider the following
statements:
a) resistance between opposite corners
is ( 20 Omega )
is ( 7.5 Omega )
c) resistance between mid points of
opposite sides is ( 10 Omega )
d) resistance between mid points of
adjacent sides is ( 15 Omega )
A. a and dare correct
B. b and d are correct
C. ( b ) and ( c ) are correct
D. a and b are correct
12
876A resistance col of ( 60 Omega ) is immersed in
( 42 mathrm{kg} ) of water. What is the rise in temperature of water per minute if a steady current of ( 7 mathrm{A} ) is made to flow
through the coli?
A ( cdot 10.10^{circ} mathrm{C} )
B. 9.51 ( ^{circ} mathrm{C} )
( mathbf{c} cdot 1.0^{circ} mathrm{C} )
D. ( 0.5^{circ} mathrm{C} )
12
877Which of the two meters, voltmeter or
potentiometer, is preferred to measure the emf of a battery? Why?
12
878Assertion
Drift velocity of electrons is
independent of time.
Reason
Electrons are accelerated in the
presence 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
879A battery having an emf of 12 Volt and an internal resistance of ( 2 Omega ) is
connected to another battery having an
emf of 18 Volt and an internal
resistance of ( 2 Omega ) in such a way that they
are opposing each other and the circuit is closed. Calculate the following.
1. Current flowing in the circuit.
2. Electrical power in the two batteries.
3.Terminal voltage of the two batteries.
4. Electric power consumed in the batteries.
12
880Our body can conduct electric current.
A. True
B. False
12
881In the circuit shown, the heat produced in ( 5 Omega ) resistor is 10 calorie/sec. The heat
produced/sec in ( 4 Omega ) resistor will be :
A . 1 cal
B . 2 cal
( c .3 ) cal
D. 4 cal
12
882( boldsymbol{P}=boldsymbol{I}^{n} times boldsymbol{R}(text { where } mathrm{P}=text { Power, } mathrm{R}= )
Resistane, I= Current)
The value of ( n )
A .
B. –
c. 1
D.
12
883An electrical appliance is rated at 1000
KVA, 220V. If the appliance is operated for 2 hours, calculate the energy consumed by the appliance in:
(i) kWh.
(ii) joule.
12
884The magnitude of electric field at different points along the length of the rod is given by
A ( cdot frac{V_{o}}{L^{2}}(L-X) )
B. ( frac{V_{o}}{(L+X)} )
c. ( frac{V_{o}}{L} )
D. ( frac{V_{o}}{2 L} )
12
885When a resistance of 2 ohms is
connected across the terminals of a
cell,the current is 0.5 A. When the
resistance is increased to 5 ohms,the current becomes 0.25 A. The e.m.f. of the cell is :-
A . 1.0
B. 1.5
c. ( 2.0 v )
D. 2.5
12
886In the circuit shown here, the cell is
ideal with emf of 2 volt. Then
This question has multiple correct options
A. no current flows in the galvanometer
B. a current of ( 0.2 A ) flows through galvanometer
c. potential difference across ( C_{1} ) is ( 1.2 V )
D. potential difference across ( C_{2} ) is ( 1.0 % ).
12
887A material that lets electricity to pass through it is called a/an-
A. Electrical appliances
B. Electrical conductor
c. Electrical insulator
D. None of these
12
888If the length of the filament of a heater is reduced by ( 25 % ), the power of the heater will
A. increase by about ( 25 % )
B. increase by about ( 33 % )
c. decrease by about ( 25 % )
D. decrease by about ( 33 % )
12
889The wire used in the arrangement shown in the figure has a resistance of ( r Omega ) per metre. The equivalent resistance
between points ( A ) and ( B ) is:
( ^{A} cdotleft(frac{6}{11}right)^{r} )
в. ( frac{2 pi r}{(pi+1)} )
c. ( frac{6 pi r}{(16+3 pi)} )
D. ( frac{3 pi r}{(10+3 pi)} )
12
890Calculate the current through the circuit and the potential difference across the diode shown in figure. The
drift current for the diode is ( 20 mu A )
12
891For a heater rated at ( 4 k W ; 220 V )
Calculate the resistance of the heater
element.
A . ( 20 Omega )
B . ( 21.6 Omega )
c. ( 200 Omega )
D. ( 12.2 Omega )
12
892A solid spherical non-conductor of radius ( 5 mathrm{cm} ) has the potential of ( 50 mathrm{V} ) at its outer surface. The potential at its center is
A .100
B. 75 v
c. zero
D. 50 v
12
893At room temperature, ( 27^{circ} mathrm{C} ), the resistance of a heating element is
100 ( Omega ). What is the temperature(in ( ^{circ} C ) )
of the element if the resistance is found
to be ( 117 Omega ) ? Given that the temperature coefficient of the material of the
resistor is ( 1.70 times 10^{-4} C^{-1} )
12
894The device used to generate large amount of electricity is
A . electric cell
B. storage battery
c. solar cell
D. electric generator
12
895In which of the following cells, the potential difference between the
terminals of a cell exceeds its emf.
(a)
(b)
(No current)
( (mathbf{d}) )
( (c) )
( A )
B. ( b )
( c )
D. ( d )
12
896Sl unit of resistance is volt.
A. True
B. False
12
897Sl unit of electric power is12
898Draw a labeled diagram of the experiment explaining Ohm’s law.12
899Draw a circuit diagram of an electric circuit containing a cell, a key, an ammeter, a resistor of ( 4 Omega ) in series with
a combination of two resistors ( (8 Omega )
each ) in parallel and a voltmeter across parallel combination. Each of them dissipate maximum energy and canwithstand a maximum power of
( 16 W ) without melting. Find the
maximum current that can flow
through the three resistors.
12
900A steady current flows in a metallic
conductor of non-uniform cross-section.
The quantity/quantities constant along the length of the conductor is /are
A. current, electric current and drift velocity
B. drift speed only
c. current and drift speed only
D. current only
12
901A cell of emf ( boldsymbol{E} ) Volt with no internal
resistance is connected to a wire whose
cross section changes. The wire has
three sections of equal length. The
middle section has a radius ( a ), whereas
the radius of the outer two sections is
2a. The ratio of the potential difference
across section ( A B ) to the potential
difference across section ( C A ) is :
( A )
B. 4
( c cdot frac{1}{2} )
D.
12
902In the given circuit diagram calculate
the current ( I_{2} ) through the resistor of
( mathbf{1 0 Omega} )
12
903A silicon piece and a silver piece are connected in series and a potential
difference is applied between their free ends. The potential difference applied
on them are ( V_{1} ) and ( V_{2} ) respectively
They are then cooled to ( 200 K . ) Now
A ( cdot V_{1} ) increases and ( V_{2} ) decreases
B. Both increase
c. Both decrease
D. ( V_{1} ) decreases and ( V_{2} ) increases
12
904Draw labelled graphs to show how
electrical resistance varies with
temperature for:
(a) A piece of carbon.
12
905Which of the following quantities do not change when a resistor connected to a
battery is heated due to the current?
A . Resistance
B. Resistivity
c. Drift velocity
D. Free electron density
12
906A metallic conductor at ( 10^{circ} mathrm{C} ) connected
in the left gap of Meter Bridge gives balancing length ( 40 mathrm{cm} . ) When the
conductor is at ( 60^{circ} mathrm{C} ), the balance point
shifts by ( 5 mathrm{cm} . ) The temperature coefficient of resistance of the material
of the wire
A . (1 / 210) / ( ^{circ} mathrm{C} )
B. (1 / 220) / ( ^{circ} mathrm{C} )
( c cdot(1 / 200) /^{prime} c )
D. (1 / 201) / ( ^{circ} mathrm{C} )
12
907The analogous term to voltage.
A. True
B. False
12
908Resistance of a wire at ( 20^{circ} C ) is ( 20 Omega ) and
at ( 500^{circ} mathrm{C} ) is ( 60 Omega . ) At what temperature
its resistance is ( 25 Omega )
( mathbf{A} cdot 160^{circ} C )
B. ( 250^{circ} mathrm{C} )
( mathbf{c} cdot 100^{circ} mathrm{C} )
D. ( 80^{circ} mathrm{C} )
12
909In the electric network shown in the
figure, use Kirchhoff’s rules to calculate
the power consumed by the resistance
( R=4 Omega )
12
910The number of electric lines of force that
radiate outwards from ( 8.85 mu mathrm{C} ) of charges
in a vacuum is:
A ( cdot 10^{-6} )
– ( ^{-6}-10 )
B. ( 10^{-12} )
( c cdot 10^{12} )
D. ( 10^{circ} )
12
911When two unknown resistors are
connected in series with a battery, ( 225 W ) power is delivered to the
combination with a total current ( 5 A ). For
the same total current ( 50 W ) is delivered
when the resistors are connected in
parallel. Find the ratio of the two resistances
( A cdot 2 )
B. 5
( c cdot 4 )
D. 10
12
912What is the alternative term used for
metre bridge?
12
913Which of the above is incosistent for the
given meter bridge:
( begin{array}{lll}text { 1. } & 1000 Omega & text { 60 cm } \ text { 2. } & 100 Omega & text { 13 cm } \ text { 3. } & 10 Omega & 1.5 mathrm{cm} \ text { 4. } & 1 Omega & 1 mathrm{cm}end{array} )
( A )
B.
( c )
( D )
12
914Wires ( A ) and ( B ) have resistivities ( rho_{A} ) and
( boldsymbol{rho}_{B},left(rho_{B}=2 rho_{A}right) ) and have lengths ( l_{A} ) and
( l_{B} . ) If the diameter of the wire ( B ) is twice
that of ( A ) and the two wires have same
resistance, then ( frac{l_{B}}{l_{A}} ) is:
( A cdot 2 )
B.
c. ( 1 / 2 )
D. ( 1 / 4 )
12
915A current ( I ) flows through a uniform
wire of diameter ( d ) when the mean
electron drift velocity is ( v . ) The same
current will flow through a wire of diameter ( frac{d}{2} ) made of the same material if the mean drift velocity of the electron
is
A. ( frac{v}{4} )
в. ( frac{v}{2} )
( c cdot 2 v )
D. ( 4 v )
12
916resistances are connected as shown in
the figure. Initially resistance ( boldsymbol{P}=4 Omega )
and the neutral point ( N ) is at ( 60 c m )
from ( A . ) Now an unknown resistance ( boldsymbol{R} )
is connected in series to ( boldsymbol{P} ) and the new
position of the neutral point is at ( 80 c m )
from ( A ). The value of unknown
resistance ( boldsymbol{R} ) is :
( mathbf{A} cdot 6 Omega )
B. ( 7 Omega )
c. ( frac{33}{5} Omega )
D. ( frac{20}{3} Omega )
12
917Figure shows a potentiometer circuit
for comparison of two resistances. The
balance point with a standard resistor
( R=10.0 Omega ) is found to be ( 58.3 mathrm{cm}, ) while
that with the unknown resistance ( X ) is
( 68.5 mathrm{cm} . ) Determine the value of ( mathrm{X} ). What
might you do if you failed to find a balance point with the given cell of emf
( epsilon ? )
12
918As the temperature of a conductor
increases, its resistivity and
conductivity change. The ratio of resistivity to conductivity
A. increases
B. decreases
c. remains constant
D. may increase or decrease depending on the actual temperature
12
919A steady current flow in a metallic conductor of non-uniform cross-section.
The quantity/quantities remaining constant along the whole length of the conductor is/are:
A. current, electric field and drift speedd
B. drift speed only
c. current and drift speed
D. current only
12
920If each capacitors has capacitance ( c ) in
the given figure, then find ( C_{A B} )
( A )
в. ( C / 2 )
( 3 C / 2 )
2. none of the abov
12
921Assertion
If the length of the conductor is doubled, the drift velocity will become half of the original value (keeping potential difference unchanged).
Reason
At constant potential difference, drift
velocity is inversely proportional to the length of the conductor.
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
922Write the colour code for ( 4.7 ~ K Omega pm )
( 10 % )
12
923Find the potentials of points ( A ) and ( B: )
A ( cdot V_{A}=+10 V ; V_{B}=0 V )
B . ( V_{A}=+7.5 V ; V_{B}=-2.5 V )
c. ( V_{A}=+2.5 V ; V_{B}=-7.5 V )
D. ( V_{A}=+0 V ; V_{B}=-10 V )
12
924A cell develops the same power across
two resistance ( boldsymbol{R}_{1} ) and ( boldsymbol{R}_{2} ) seprarately.The internal resistance of the cell is :
A ( cdot R_{1}+R_{2} )
в. ( frac{R_{1}+R_{2}}{2} )
c. ( sqrt{R_{1} R_{2}} )
D. ( frac{sqrt{R_{1} R_{2}}}{2} )
12
925Two resistances are connected in two
configurations- series or parallel. Which represents the parallel combination?
( A, A )
B. A and B both
( c . )
D. none of these
12
926If the total electrical power consumed when they are both connected to this
emf source in parallel is ( boldsymbol{X} boldsymbol{P}_{1}+boldsymbol{Y} boldsymbol{P}_{2} )
Find out the value of ( X+Y ) ?
12
927The four wires from a larger circuit
intersect at junction A a shown. What is
the magnitude and direction of the
current between points ( A ) and ( B ? )
A. 2 A from ( A ) to ( B )
B. 2 A from ( B ) to ( A )
C. 3 A from A to B
D. 3 A from B to A
12
928Three identical batteries each emf 4 V
and zero of negligible internal
resistance are connected as shown
in figure below. The potential difference
between the poilints ( A ) and ( Gleft(V_{A}-V_{G}right) )
A . 4 v
B . ( -4 V )
( c cdot 8 v )
( mathbf{D} cdot-8 V )
12
929For the coil shown in the figure what
must be done to induce a clockwise
current?
A. Either move the north pole of a magnet down into the coil, or move the south pole of the magnet up out of the coil
B. Either move the south pole of a magnet down into the coil, or move the north pole of the magnet up out of the coil
C. Move either pole of the magnet down into the coil
D. Move either pole of the magnet up into the coil
12
930What is the total resistance and current
in the circuit?
A. ( 2.5 Omega, 0.4 A )
B. ( 2 Omega, 1.6 A )
c. ( 2.5 Omega, 1.6 A )
D. ( 6 Omega, 1.6 A )
12
931In an electric iron heat produced is same, whether it is connected across an
A.C. source or across 50 constant
voltage. R.M.S, value of the A.C. voltage applied is
A . ( 50 V )
B. Zero
c. ( 50 sqrt{2} V )
D. ( frac{50}{sqrt{2}} V )
12
932An electric refrigerator rated ( 600 W )
operates 8 hours / day. What is the cost
of the energy to operate it for 30 days at Rs.4.00 per k Wh?
12
933Unit of electric power may also be expressed as:
A. volt ampere
B. kilowatt hour
c. watt second
D. joule secono
12
934An electric bulb is designed to draw
power ( P_{0} ) at voltage ( V_{0} . ) If the voltage is
( v, ) it draws a power ( P, ) then
( ^{A} cdot P=left(frac{V}{V_{0}}right) P_{0} )
в. ( P=left(frac{V_{0}}{V}right) P_{0} )
( ^{mathrm{c}} P=left(frac{V_{0}}{V}right)^{2} P_{0} )
( P=left(frac{V}{V_{0}}right)^{2} P_{0} )
12
935Wheatstones’s bridge cannot be used for measurement of very resistances.
A . high
B. low
c. low(or) high
D. zero
12
936( A, B, C ) and ( D ) are four coils of wires of 2,2
2 and 3 ohm resistances respectively and are arranged to form a Wheatstone bridge.The resistance which the coil ‘D’ must be shunted in order that the
bridge may be balanced is:
A . ( 4 Omega )
B. 6.
( c .3 Omega )
D. ( 8 Omega )
12
937A rectangular carbon block has
dimensions ( 1.0 mathrm{cm} times 1.0 mathrm{cm} times 50 mathrm{cm} )
Resistance are measured first across
two square ends and then across two
rectangular ends, respectively. If
resistivity carbon is ( 3.5 times 10^{-5} Omega m )
then value of measured resistances
respectively are
( mathbf{A} cdot 17.5 times 10^{-2} Omega, 7 times 10^{-5} Omega )
B . ( 7 times 10^{-5} Omega, 7.5 times 10^{-2} Omega )
C. ( 17.5 times 10^{-4} Omega, 7 times 10^{-7} Omega )
D. ( 7.5 Omega, 7 times 10^{-2} Omega )
12
938Statement-1: The resistivity of
a semiconductor decreases with
increases of temperature
Statement-2: In a conducting solid, the rate of collision between free electrons
and ions increases with the increase of
temperature
A. Statement-1 is true and Statement-2 is correct explanation for Statement-
B. Statement-1 is true and Statement-2 is NOT the correct explanation for Statement-
c. Statement- 1 is true, Statement- 2 is false
D. Statement-1 is false, Statement-2 is true
12
939Find the equivalent resistance between ( A ) and ( E ) (The resistance of each
resistor is ( R ).)
( A cdot frac{7}{12} F )
3. ( frac{7}{13} ) f
( c cdot frac{7}{15} )
D. ( frac{8}{13} R )
12
940An electric bulb of resistance ( 480 Omega ) is
connected to ( 220 V . ) Find electric energy
consumed in ( 10 s )
A . ( 1000 J )
в. ( 9600 J )
c. 1008.35
D. ( 1118.7 J )
12
941Two resistances are connected in two
gaps of a metre bridge. The balance point is ( 20 mathrm{cm} ) from the zero end. ( A )
resistance of ( 15 Omega ) is connected in series with the smaller of the two. The null
point shifts to ( 40 mathrm{cm} . ) The value of the smaller resistance in ohms is.
A . 3
B. 6
c. 9
D. 12
12
942In the circuits shown below the
ammeter ( A ) reads ( 4 a m p ) and the
voltmeter ( V ) reads 20 volts. The value of
the resistance ( boldsymbol{R} ) is
A. Slightly more than 5 ohms
B. Slightly less than 5 ohms
c. Exactly 5 ohms
D. None of the above
12
943Electricity is a form of
A. Force
B. Energy
c. Tension
D. Shock
12
944A uniform but time varying magnetic field is present in a circular region of radius R. The magnetic field is perpendicular and into the plane of the loop and the magnetic of field is increasing at a constant rate ( alpha . ) There is
a straight conducting rod of length ( 2 mathrm{R} ) placed as shown in figure. The magnitude of induced emf across the rod is
This question has multiple correct options
( mathbf{A} cdot 60^{circ} )
B. ( 90^{circ} )
( c cdot 30^{circ} )
D. ( 20^{circ} )
12
945A wire has a diameter of ( 0.2 m m ) and a
length of ( 50 mathrm{cm} . ) The specific resistance
of it’s material is ( 40 times 10^{-6} ) ohmcm.
The current through it, when a potential difference of ( 2 V ) is applied across it, is
( mathbf{A} cdot 3 cdot 14 A )
B . ( 31.4 A )
c. ( 0.314 A )
D. ( 0.0314 A )
12
946The resistivity of a wire varies with
A . length
B. cross-section
c. mass
D. material
12
947The potential difference across a ( 6 Omega )
resistor is ( 12 V . ) The current flowing in
the resistor will be
A ( .4 A )
B. 2A
( c cdot 0.5 A )
D. 1A
12
948Metals have
A. Zero resistivity
B. High resistivity
C . Low resistivity
D. Infinite resistivity
12
949A cell of e.m.f ( 3 V ) and internal
resistance ( 4 Omega ) is connected to two
resistance ( 10 Omega ) and ( 24 Omega ) joined in
parallel. Find the current through each resistance using kirchhoff’s laws.
12
950is the electrical
energy produced or consumed per unit
time.
12
951The colour code of a resistor is brown, black and brown. Then the value of
resistance is
A . ( 10 Omega )
в. ( 100 m Omega )
c. ( 0.1 k Omega )
D. ( 100+5 % )
12
952In a Wheatstones’s bridge, three resistances ( P, Q ) and ( R ) are connected in the three arms and the fourth arm is
informed by two resistances ( S_{1} ) and ( S_{2} ) connected in parallel. The condition for the bridge to be balanced will be
( ^{mathrm{A}} cdot frac{P}{Q}=frac{2 R}{S_{1}+S_{2}} )
B. ( frac{P}{Q}=frac{Rleft(S_{1}+S_{2}right)}{S_{1} S_{2}} )
c. ( frac{P}{bar{Q}}=frac{Rleft(S_{1}+S_{2}right)}{2 S_{1} S_{2}} )
D. ( frac{P}{Q}=frac{R}{S_{1}+S_{2}} )
12
953Sensitivity of potentiometer can be increased by
A. increasing the e.m.f. of the cell.
B. increasing the length of the potentiometer.
c. decreasing the length of the potentiometer wire.
D. none of these.
12
954Which of the following represents Ohm’s Law?
A. ( 1=Q . )
B. I = V.R
( c cdot 1=frac{R}{V} )
( D cdot 1=frac{V}{R} )
12
955Three unequal resistance are connected in parallel. Two of these resistances are
in the ratio ( 1: 2 . ) The equivalent
resistance of these three connected in
parallel is ( 1 Omega . ) What is the highest resistance value among these three resistances if no resistance is
fractional?
A . ( 10 Omega )
B. ( 8 Omega )
( c .15 Omega )
D. ( 6 Omega )
12
956A uniform electric field ( overrightarrow{boldsymbol{E}} ) exists
between 2 plates, a charged particle enters the space between the plates and perpendicular to ( vec{E} ). The path of the particle between the plates is a:
A. straight line
B. hyperbola
c. parabola
D. circle
12
957Match the following12
958In the pictured circuit, If the reading of
voltmeter 1 is ( 3.0 V ) the reading of
ammeter 2 is ( 20 A ) and the reading of
voltmeter 3 is ( 5.0 ~ V, ) what is the
terminal voltage of the battery?
( mathbf{A} cdot 8.0 V )
B. ( 3.0 V )
c. ( 5.0 V )
D. ( 10.0 V )
E. Not enough is given to answer this
questio
12
959Four identical cells of emf ( boldsymbol{E} ) and
internal resistance ( r ) are to be
connected in series. Suppose if one of the cell is connected wrongly, the equivalent emf and effective internal resistance of the combination is
( mathbf{A} cdot 4 E ) and ( 4 r )
B. ( 4 E ) and ( 2 r )
( mathbf{c} cdot 2 E ) and ( 4 r )
D. ( 2 E ) and ( 2 r )
12
960Two cells of equal emf and of internal
resistances ( r_{1} ) and ( r_{2}left(r_{1}>r_{2}right) ) are
connected in series. On connecting this combination to an external resistance
( mathrm{R}, ) it is observed that the potential difference across the first cell becomes
zero. The value of R will be.
( mathbf{A} cdot r_{1}+r_{2} )
В. ( r_{1}-r_{2} )
c. ( frac{r_{1}+r_{2}}{2} )
D. ( frac{r_{1}-r_{2}}{2} )
12
961(a) In a metre bridge [Fig.], the balance point is found to be at ( 39.5 mathrm{cm} ) from the
end ( A, ) when the resistor ( Y ) is of ( 12.5 Omega )
Determine the resistance of X. Why are the connections between resistors in a
Wheat stone or meter bridge made of thick copper strips?(b) Determine the balance point of the bridge above if ( mathbf{X} )
and ( Y ) are interchanged.(c) What
happens if the galvanometer and cell
are interchanged at the balance point of the bridge? Would the galvanometer show any current?
12
962In the circuit shown in figure, the ( 5 Omega )
resistance develops 20.00 cal/s due to the current flowing through it. The heat
developed in ( 2 Omega ) resistance (in cal/s) is
A. 23.8
B. 14.2
( c cdot 11.9 )
D. 7.
12
963A potentiometer is connected between and B and the balance point is obtained
at ( 203.6 mathrm{cm} . ) When the end of the
potentiometer connected to B is shifted to ( C, ) then the balance point is obtained
at ( 24.6 mathrm{cm} . ) If now the potentiometer be connected between ( mathrm{B} ) and ( mathrm{C} ), the balance
point will be at:
A. ( 179.0 mathrm{cm} )
В. ( 197.2 mathrm{cm} )
c. ( 212.0 mathrm{cm} )
D. ( 228.0 mathrm{cm} )
12
964The infinity resistance plug in a postoffice box has
A. an airgap only.
B. a resistance coil of infinite resistance.
c. largest resistance available in box.
D. resistance of the coil 5000 ( Omega )
12
965The circuit below shows three identical
resistors labeled ( 1,2, ) and ( 3 . ) The reading on the ammeter is 12.0 A. How much
current flows in each resistors?
A. 4.0 A
в. 12.0 А
c. 36.0 А
D. we cannot determine the current values without knowing the resistor va
E. we cannot determine the current values without knowing the batter
12
966In an experiment of verification of
Ohm’s law, following observations are obtained:
Potential difference 0.5
( begin{array}{lll}text { 1.0 } & text { 1.5 } & text { 2.0 }end{array} ) ( v ) (in volt’)
Current
in 0.2
ampere
From observation table the resistance
in circuit is
A. ( 2.5 Omega )
в. ( 2 Omega )
( c .5 Omega )
D. ( 3 Omega )
12
967A cell can be balanced against ( 110 mathrm{cm} )
and ( 100 mathrm{cm} ) of potentiometer wire respectively, with and without being short-circuited through a resistance of
10Omega. Its internal resistance is :
A . ( 1.0 Omega )
B. ( 0.5 Omega )
c. ( 2.0 Omega )
D. zero
12
968A cell of emf ( E ) and internal resistance ( r )
is connected across a resistance ( r ). The
potential difference between the terminals of the cell must be
A. ( E )
B. ( E / 2 )
c. ( E / 4 )
D. ( 3 E / 2 )
12
969A resistor of resistance ( R ) is connected
to an ideal battery. If the value of ( boldsymbol{R} ) is
decreased, the power dissipated in the resistor will
A. Increase
B. Decrease
c. Remains unchanged
D. None of these
12
970Two point charges each of ( 1 C )
separated by 1 m distance experience a
force of ( 5.6 times 10^{9} N ) in vacuum. How
much force is experienced by them if they are immersed in water., keeping the distance of separation between them same?
( boldsymbol{K}=mathbf{8 0} ) for water.
12
971By increasing the temperature the resistance of a conductor
A. increases
B. decreases
c. remains constant
D. initially increases then decreases
12
972A battery of e.m.f. ( 3.0 mathrm{V} ) supplies current through a circuit in which the
resistance can be changed. A high resistance voltmeter is connected
across the battery. When the current is
( 1.5 mathrm{A}, ) the voltmeter reads ( 2.7 mathrm{V} ). The
internal resistance of the battery is
A . ( 4 Omega )
в. ( 1.2 Omega )
c. ( 0.2 Omega )
D. 2Omega
12
973A cell balances against a length of
( 200 mathrm{cm} ) on a potentiometer wire, when it
is shunted by a resistance of 8Omega. The balancing length reduces by ( 40 mathrm{cm} )
when it is shunted by a resistance of ( 4 Omega ) Calculate the balancing length when the cell is in open circuit. Also calculate
the internal resistance of the cell.
12
974Two cells of emf’s approximately ( 5 V ) and
10V are to be accurately compared
using a potentiometer of length ( 400 mathrm{cm} )
A. The battery that runs the potentiometer should have voltage of ( 8 mathrm{V} )
B. The battery of potentiometer can have a voltage of ( 15 mathrm{V} ) and ( R ) adjusted so that the potential drop across the wire slightly exceeds ( 10 mathrm{V} )
C. The first portion of ( 50 mathrm{cm} ) of wire itself should have a potential drop of ( 10 mathrm{v} )
D. Potentiometer is usually used for comparing resistances and not voltages
12
975Write Ohm’s law. Write name of devices
( X ) and ( Y ) in the given circuit related to
Ohm’s Law.
12
976The specific resistance of a rod of
copper as compared to that of thin wire of copper is
A. more
B. less
c. same
D. depends upon the length and area of wire
12
977A voltmeter of reading up to ( 1000 m V ) is calibrated by a potentiometer. An emf of ( 1.08 V ) is balanced across ( 5.4 m ) length
of the wire. When voltmeter reading is ( 0.9 V, ) the balancing length is ( 4.55 m )
The error in the voltmeter reading is:
A. -0.01mV
B. 0.5 mv
c. ( 0.25 mathrm{mv} )
D. No error
12
978A wire of radius r and another wire of
radius ( 2 r, ) both of same material and
length are connected in series to each other. The combination is connected
across a battery. The ratio of the heats produced in the two wires will be
A . 4.00
B . 2.00
c. 0.50
D. 0.25
12
979For a metallic wire, the ratio of voltage
to corresponding current is?
A. Independent of temperature
B. Increases with rise in temperature
C. Increases or decreases with rise in temperature depending upon the metal
D. Decreases with rise in temperature
12
980If current ( boldsymbol{I}_{1}=mathbf{3} boldsymbol{A} sin omega boldsymbol{t} ) and ( boldsymbol{I}_{2}=boldsymbol{4} boldsymbol{A} )
( cos omega t, ) then ( I_{3} ) is :
A .5 Asin ( left(omega t+53^{circ}right) )
B. 5 Asin ( left(omega t+37^{circ}right) )
c. 5 Asin ( left(omega t+45^{circ}right) )
D. 5 Asin ( left(omega t+30^{0}right) )
12
981Which of the following are the properties of fuse wire?
A. Made of alloy of tin
B. Has a low melting point
c. connected in series with main supply
D. All of the above
12
982Space between two concentric spheres
of radii ( r_{1} ) and ( r_{2}, ) such that ( r_{1}<r_{2}, ) is
filled with a material of resistivity ( rho )
Find the resistance between inner and
outer surface of the material.
A ( cdot frac{r_{1}}{r_{2}} frac{rho}{2} )
В. ( frac{r_{2}-r_{1}}{r_{r} r_{2}} frac{rho}{4 pi} )
c. ( frac{r_{1} r_{2}}{r_{2}-r_{1}} frac{rho}{4 pi} )
D. None of these
12
983The resistances in left and right gap of a meter bridge are ( 20 Omega ) and ( 30 Omega ) respectively. When the resistance in the
left gap is reduced to half its value, the balance point shifts by
A. ( 15 mathrm{cm} ) to the right
B. ( 15 mathrm{cm} ) to the left
c. ( 20 mathrm{cm} ) to the right
D. ( 20 mathrm{cm} ) to the left
12
984Describe briefly with the help of a circuit diagram, how a potentiometer is used to determine the internal
resistance of cell.
12
985In the figure ( A B ) is a wire of length 100
( mathrm{cm} ) whose resistance is ( 5 Omega ). If
flowing in the wire AB is
A . ( 0.1 mathrm{A} )
B. 0.5
( c cdot 1 A )
D. ( 1.4 A )
12
( P=50 Omega ) and ( Q=100 Omega, ) the null point
is obtained at ( C ) where ( A C=33 mathrm{cm} )
When the resistors are interchanged, the null point is found at ( C ) with ( A C= )
( 67 mathrm{cm} . ) The systematic error in this
experiment seems to be due to non-
coincidence of ( A ) and ( B ) with 0 cm mark
and ( 100 mathrm{cm} ) mark respectively. If these
and errors are equivalent to ( ^{prime} a^{prime} c m ) and
( b^{prime} c m ) respectively, then they are.
A. 0 and 1
B. 1 and 0
c. 0.33 and 0.33
D. 1 and 1
12
987Resistance of a conductor of length ‘x’ is
r’. If its area of cross-section is ‘a’, What
is its resistivity? What is its unit?
12
988( mathbf{A} )
( 2 Omega ) resistor is connected in series
with ( R Omega ) resistor. This combination is
connected across a cell. When the
potential difference across ( 2 Omega ) resistor is balanced on potentiometer wire, null
point is obtained at length of 300cm.
When the same procedure is repeated for ( R Omega ) resistor, null point is obtained at
length ( 350 mathrm{cm}, ) value of ( mathrm{R} ) is:
A. 5
в. 3.33
c. 4.6
D. 2.83
12
989What does the slope of V-I graph for a conductor represent?
A. Capacitance
B. Power
c. Inductance
D. Resistance
12
990At temperature ( 0 K, ) the germanium behaves as a/an
A. conductor
B. insulator
c. super-conductor
D. ferromagnetic
12
991Four wires made of same material have
different lengths and radii. The wire having more resistance in the following is
A ( .1=100 mathrm{cm} mathrm{r}=1 mathrm{mm} )
B. ( 1=50 mathrm{cm} mathrm{r}=2 mathrm{mm} )
c. ( 1=100 mathrm{cm} mathrm{r}=1 / 2 mathrm{mm} )
D. ( 1=50 mathrm{cm} mathrm{r}=1 / 2 mathrm{mm} )
12
992A conductor carries a current of ( 50 mu A ) If the area of cross-section of the
conductor is ( 50 mathrm{mm}^{2} ), then value of the
current density in ( A m^{-2} ) is
A . 0.5
B.
( c cdot 10^{-3} )
D. ( 10^{-6} )
12
993( mathbf{A} )
( 5 V ) battery of negligible internal
resistance is connected across a ( 200 V )
battery and a resistance of ( 39 Omega ) as
shown in the figure. Find the value of the
current
12
994A cell of emf 5 V can supply a total energy of ( 9000 mathrm{J}, ) then the total charge that can be obtained from the cell would
be
A . 180
B. 18000
c. 1800
D. 18
12
995It is desired to make a long cylindrical
conductor whose temperature
coefficient of resistivity at ( 20^{circ} C ) will be close to zero. If such a conductor is
made by assembling alternate disks of iron and carbon, Find the ratio of the
thickness of a carbon disk to that an
iron disk. (For carbon, ( boldsymbol{rho}=mathbf{3 5 0 0} times )
( 10^{-8} Omega m ) and ( alpha=-0.50 times 10^{-3}^{circ} C^{-1} )
for iron, ( rho=9.68 times 10^{-8} Omega ) and ( alpha= )
( left.mathbf{6 . 5} times mathbf{1 0}^{-mathbf{3} circ} mathbf{C}^{-mathbf{1}}right) )
A . 0.36
B. 0.036
( c .1 . )
D . 2.0
12
996A cell of emf ( e_{1} ) in the secondary circuit gives null deflection for ( 1.5 mathrm{m} ) length of potentiometer of wire length ( 10 mathrm{m} ). If
another cell of emf ( e_{2} ) is connected in
series with ( e_{1} ) then null deflection was
obtained for ( 2.5 mathrm{m} ) length. Then ( mathrm{e}_{1}: mathrm{e}_{2} ) is:
A . 3: 5
B. 5: 3
( c cdot 3: 2 )
D. 2: 3
12
997Obtain an expression for e.m.f. induced in a coil rotating with uniform angular velocity in a uniform magnetic field. Show graphically the variation of e.m.f.
with time ( (t) )

Resistance of a potentiometer wire is ( 0.1 Omega / c m . ) A cell of e.m.f. ( 1.5 V ) is balanced at ( 300 mathrm{cm} ) on this
potentiometer wire. Calculate the current and balancing length for
another cell of e.m.f. ( 1.4 mathrm{V} ) on the same
potentiometer wire

12
998In figure given below, find the value of
resistance ( X ) for which points ( A ) and ( B ) are at the same potential:
12
999In the circuit shown below
This question has multiple correct options
A. Current flowing in the circuit is ( 200 mathrm{mA} )
B. Power supplied by the battery is 2 watt
c. Current from ( X ) to ( Y ) is zero
D. Potential difference across ( 10 Omega ) is equal to zer
12
1000Two bar magnets are placed on a piece of cork which floats on water. The magnets
are so placed that their axis are mutually
perpendicular. Then the cork
A. rotates
B. moves a side
c. oscillates
D. neither rotates nor oscillates
12
1001Two resistors of ( 2 Omega ) and ( 4 Omega ) are
connected in parallel. Two more
resistors ( 3 Omega ) and ( 6 Omega ) are also connected
in parallel. These two combinations are in series with a battery of emf ( 5 V ) and internal resistance ( 0.7 Omega . ) Calculate the
current through ( 6 Omega ) resistor.
12
1002A silver wire has temperature
coefficient of resistivity ( 4 times 10^{-3} /^{circ} C )
and its resistance at ( 20^{circ} mathrm{C} ) is ( 10 Omega )
Neglecting any change in dimensions due to the change in temperature, its
resistance at ( 40^{circ} mathrm{C} ) is?
A . ( 0.8 Omega )
в. ( 1.8 Omega )
( c .9 .2 Omega )
D. ( 10.8 Omega )
E . ( 11.6 Omega )
12
1003Shown in the figure below is a meter-
bridge set up with null deflection in the
galvanometer

The value of the unknown resistor ( boldsymbol{R} ) is
A. ( 13.75 Omega )
B. ( 220 Omega )
( c cdot 110 Omega )
D. ( 55 Omega )

12
1004The resistance of wire is ( 20 Omega ). The wire
is stretched to three time its length. Then the resistance will now be
( mathbf{A} cdot 6.67 Omega )
B. ( 60 Omega )
c. ( 120 Omega )
D. ( 180 Omega )
12
1005The effective resistance between the
points ( X ) and ( Y ) in the given circuit is
( A cdot 8 / 3 Omega )
B. ( 8 Omega )
( c .4 Omega )
D. ( 2 Omega )
12
1006The drift speed of the conduction
electrons is:
A. ( 2.5 mathrm{cm} / mathrm{s} )
B. ( 5 mathrm{cm} / mathrm{s} )
c. ( 7.5 mathrm{cm} / mathrm{s} )
D. ( 15 mathrm{cm} / mathrm{s} )
12
1007What is the current in the circuit shown
(Figure)
( mathbf{A} cdot 1.5 A )
B. ( 0,5 A )
( mathbf{c} .2 .5 A )
D. None of these
12
1008At what temperature would the resistance of a copper conductor be
double its resistance at ( 0^{circ} mathrm{C} ? ) Given ( alpha )
for copper is ( 3.9 times 10^{-3}^{circ} C^{-1} )
A ( cdot 256.4^{circ} mathrm{C} )
в. ( 512.8^{circ} mathrm{C} )
( c cdot 100^{circ} mathrm{C} )
D. 256.4k
12
1009toppr
wires have same length, but thickness
of wire ( mathrm{B} ) is twice that of wire ( mathrm{A} ). The
conducting wires connecting ( A ) and ( B )
to the ideal cell are resistance less. The
dependence of electric potential on
position along the length of two wires is given in option.
( A )
B.
( c )
D.
( E )
12
1010A part of an electric circuit is shown in
the figure below :
Using Kirchhoff’s 2nd law, find the
current ( I ) flowing through the ( 4 Omega ) resistor
12
1011The specific resistance of a metal wire
is ( 64 times 10^{-6} Omega times c m ., ) the length is 198
( mathrm{cm} ) and the resistance is ( 7 Omega ). The radius
of wire is :-
A. ( 2.4 mathrm{cm} )
B. 0.24 cm
c. ( 0.024 mathrm{cm} )
D. ( 24 mathrm{cm} )
12
1012While studying the dependence of potential difference (V) across a
resistor on the current
(I) Passing through it, in order to determine the resistance of the resistor, a student
took 5 readings for different values of current and plotted a graph between
and I. He got a straight line graph passing through the origin. What does the straight line signify? Write the method of determining resistance of the resistor using this graph.
12
1013Three equal resistors connected in series across a source of e.m.f together dissipate 10W power. The power dissipated if the same resistors are connected in parallel across the same source of emf is
A ( . ) 1) ( 10 w )
B. 2) 30w
( c cdot 3) ) 90w
D. 4 cow
12
1014If a resistance ( 5 Omega ) is connected in the
left gap of a meter bridge and ( 15 Omega ) in the other gap then position of balancing point is
( A cdot 10 mathrm{cm} )
B. 20 cm
c. ( 25 mathrm{cm} )
D. 75 cm
12
1015A battery of emf ( 10 mathrm{v} ) and internal resistance of 0.5 ohms is connected
across ( A ) variable resistance R.The
maximum value of ( mathrm{R} ) is given by:
A . ( 0.5 Omega )
B. ( 1.00 Omega )
c. ( 2.0 Omega )
D. ( 0.25 Omega )
12
1016A conductor of non uniform cross
section is connected across a potentia
difference ( V ) as shown in the figure,

Choose the correct option regarding the
conductor
This question has multiple correct options
A. current at ( B ) is same as that of ( A )
B. current density near at the end A inside the conductor is more than the current density near the end B inside the conductor
C. resistance of thickness dx near the end B is less than
the resistance near the end
D. electric field near the end ( A ) is more than at ( B )

12
1017A wire of resistance ( 20 Omega ) is bent to form
a closed square. What is the resistance
across a diagonal of the square.
12
1018Four cells, each of emf ( E ) and internal
resistance ( r, ) are connected in series
across an external resistance ( boldsymbol{R} ). By
mistake one of the cells is connected in
reverse. Then the current in the external
circuit is:
A ( cdot frac{2 E}{4 r+R} )
в. ( frac{3 E}{4 r+R} )
c. ( frac{3 E}{3 r+R} )
D. ( frac{2 E}{3 r+R} )
12
1019Equivalent resistance between point ( mathbf{A} )
and ( mathrm{B} ) in the combination of resistance
shown is
( mathbf{A} cdot 7 / 5 Omega )
B . ( 13 / 5 Omega )
c. ( 9 / 8 Omega )
D. ( 7 / 13 Omega )
12
1020A copper wire of ( 3 m m^{2} ) cross sectional
area carries a current of 5 ampere. The magnitude of the drifty velocity for the electrons in the wire, (Assume copper to
be monovalent, ( M_{C u}=63.5 k g / k ) mol
and density of copper ( =mathbf{8 9 2 0} mathbf{k g} / mathbf{m}^{mathbf{3}} ) ).
A. ( 0.24 mathrm{m} / mathrm{s} )
В. ( 0.12 mathrm{m} / mathrm{s} )
c. ( 2.4 mathrm{m} / mathrm{s} )
D. ( 0.06 mathrm{m} / mathrm{s} )
12
1021Two 220 volt, 100 watt bulbs are connected first in series and then in
parallel. Each time the combination is connected to a 220 volt a.c.supply line. The power drawn by the combination in each case respectively will be
A. 50 watt, 100 watt
B. 100 watt, 50 watt
c. 200 watt, ( , 150 ) watt
D. 50 watt, 200 watt
12
1022The temperature coefficient of
resistance of conductor varies as
( boldsymbol{alpha}(boldsymbol{T})=boldsymbol{3} boldsymbol{T}^{2}+boldsymbol{2} boldsymbol{T} . ) If ( boldsymbol{R}_{0} ) is resistance at
( T=0 ) and ( R ) is resistance at ( T, ) then
A ( . R=R_{0}(6 T+2) )
B . ( R=2 R_{0}(3+2 T) )
C ( . R=R_{0}left(1+T^{2}+T^{3}right) )
D. ( R=R_{0}left(1-T+T^{2}+T^{3}right) )
12
1023Define the term
dielectric constant. Give its S.l.unit.
12
1024The definition of resistance given by ( R=frac{V}{I} ) holds good for:
A. conductors only
B. Metals only
c. Non-ohmic devices only
D. All conducting devices, whetheror not they obey onm’s law
12
1025The value of unknown resistance ( boldsymbol{X} ) will
be
A ( .402 .49 Omega )
3. 403 .
( c cdot 404 Omega )
D. 210Omega
12
1026State Kirchoff’s law for an electrical
network. Using these laws deduce the condition for balance in a wheatstone
bridge. Three resistors ( 2 Omega, 4 Omega ) and ( 5 Omega ) are combined in parallel. What is the total resistance of the combination?
12
1027Veena’s car radio will run from a ( 12 vee ) car
battery that produces a current of 0.20 A even when the car engine is turned off The car battery will not longer operate when it has lost ( 1.2 times 10^{6} J ) of energy. If
Veena gets out of the car, leaving the radio on by mistake, how long will it
take for the car battery to go completely dead, i.e., lose all energy?
12
1028toppr
OB are resistanceless and rotating with
constant angular velocity ( omega ) in the same
plane as that ring, about hinge point ‘0
and the separation between 0 and
( mathrm{C} ) (centre of ring) is’ ( 2 ell ) as shown in the
figure. Find the current in the rod ‘OA’ when the both rod becomes tangent
to the ring.
A. Zero
B.
[
frac{B a V}{R} e frac{-3 t}{2 C R}
]
( c )
[
frac{B a V}{R} e frac{3 t}{2 C R}
]
D.
[
frac{B a V}{R} e frac{-4 t}{2 C R}
]
E. None of the above
12
1029In the circuit shown in figure heat
developed across ( 2 Omega, 4 Omega ) and ( 3 Omega )
resistances are in the ratio of
A .2: 4: 3
в. 8: 4: 12
( c cdot 4: 8: 27 )
D. 8: 4: 27
12
1030Match the Column I with Column II.
Column Column A nn II ( mathrm{O} mathrm{h}_{mathrm{m}} )
( mathrm{i}_{mathrm{S}} )
( mathrm{applin}_{mathrm{d}} ) Whe the the
(A)
( (p) )
metals applicable
to The
(B) Ohm’s law
is not
applicable
to
( (q) )
grr
reer greater
resistivity
electrolytes,
semiconductors
( A cdot A-r, B-q, C-p )
B. ( A-p, B-r, C-q )
C. ( A-r, B-p, C-q )
D. A-q, B-r, C-p
12
1031Which of the two switches ( S_{1} ) and ( S_{2} )
shown in figure will produce short-
circuiting?
( A cdot S_{1} )
B. ( S_{2} )
c. Both ( S_{1} ) and ( S_{2} )
D. Neither ( S_{1} ) nor ( S_{2} )
12
1032Brown,black and gold is the color band on the resistor,find its resistance?
A ( cdot 10 times 10^{-2} Omega )
B. 1Omega
c. ( 100 Omega )
D. ( 10 times 10^{0} Omega )
12
1033In a potentiometer experiment the balancing with a cell is at length 240 ( mathrm{cm} . ) On shunting the cell with a resistance of ( 2 Omega ) the balancing length
becomes ( 120 mathrm{cm} . ) The internal
resistance of the cell is?
A . ( 1 Omega )
в. ( 0.5 Omega )
( c .4 Omega )
D. ( 2 Omega )
12
1034A coil made of insulated copper wire is
connected to a galvanometer. What will
happen if a bar magnet is held stationary inside the coil?
outside
opposite
12
1035A steady current is set up in a metallic wire of nonuniform cross-section How is
the rate of flow of electrons
(R) related
the area of cross-section
12
1036Assertion
(A) :When the radius of a
copper wire is doubled, its specific resistance increases
Reason
(R) :Specific resistance is independent of cross-section of
material used
A. Both A & R are true and R is the correct explanation of ( A )
B. Both A & R are true and R is not a correct explanation of
c. A is true but R is false
D. A is false but R is true
12
1037The resistance across ( mathrm{M} ) and ( mathrm{N} ) in the
given figure where each resistor shown
if of ( r Omega ) is:
( A cdot frac{r}{2} )
B. ( frac{r}{3} )
( c cdot 6 r )
D. 2r
12
1038In a potentiometer experiment of a cell of emf ( 1.25 mathrm{V} ) gives balancing length of ( 30 mathrm{cm} . ) If the cell is replaced by another cell, balancing length is found to be 40
cm. What is the emf of second cell?
( mathbf{A} cdot simeq 1.57 V )
( mathbf{B} cdot simeq 1.67 V )
( mathbf{c} . simeq 1.47 V )
( mathbf{D} cdot simeq 1.37 V )
12
1039A cell supplies a current of ( 0.9 mathrm{A} ) through a ( 2 Omega ) resistor and a current of
( 0.3 mathrm{A} ) through a ( 7 Omega ) resistor. The internal resistance of the cell is :-
A . ( 1.0 Omega )
в. ( 0.5 Omega )
c. ( 2.0 Omega )
D. ( 1.2 Omega )
12
1040State the working principle of potentiometer explain with the help of circuit diagram. How the emf of two primary cells are compared by using the potentiometer12
1041Find the net capacitance between ( A ) and
B in Fig:
( mathbf{A} cdot 5 / 2 mu F )
B . ( 2 / 5 mu F )
( mathbf{c} cdot 9 / 22 mu F )
D. ( 22 / 9 mu F )
12
1042The insulator of electricity is :
A. copper
B. silk
c. human body
D. acidulated water
12
1043Assertion
Total current entering a circuit is equal
to leaving the circuit by Kirchhoff’s law.
Reason
It is based on conservation of energy.
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
1044Assertion
A potentiometer having 10 wires is more accurate than the potentiometer
having 1 wire
Reason
potentiometer is much less
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
1045The resistance of the wire in the
platinum resistance thermometer at
ice point is ( 5 Omega ) and at steam point is
5.25 ( Omega ). When the thermometer is
inserted in an unknown hot bath its
resistance is found to be ( 5.5 Omega ). The
temperature of the hot bath is?
A ( cdot 100^{circ} mathrm{C} )
B . ( 200^{circ} mathrm{C} )
c. ( 300^{circ} mathrm{C} )
D. ( 350^{circ} mathrm{C} )
12
1046A conductor has a non-uniform section
as shown in the figure. A steady current is flowing through it. Then the drift speed of the electrons:
A. varies unpredictably
B. increases from P to Q
c. decreases from P to Q
D. is constant throughout the wire
12
1047Aluminium ( left(boldsymbol{alpha}=mathbf{4} times mathbf{1 0}^{-mathbf{3}} boldsymbol{K}^{-1}right) )
resistance of ( 60 Omega ) and carbon
( left(alpha=0.5 times 10^{-3} K^{-1}right) ) resistance ( 40 Omega )
are connected in parallel. The combination is heated. The effective
resistance is
A. Greater than ( 24 Omega )
B. Less than ( 24 Omega )
c. Greater than ( 40 Omega )
D. Greater than ( 100 Omega )
12
1048A rheostat is used in an electrical
circuit
A. to change the resistance of the circuit.
B. to change the potential difference.
c. to change the emf
D. to change the current through a particular instrument
12
1049Two wires of the same material but of
different diameters carry the same current I. If the ratio of their diameters
is ( 2: 1, ) then the corresponding ratio of their mean drift velocities will be
( A cdot 4: )
B. 1: 1
( c cdot 1: 2 )
( D cdot 1: 4 )
12
1050Appropriate material to be used in the construction of resistance boxes out of
the following is
A. copper
B. iron
c. manganin
D. aluminium
12
1051You are given n identical wires, each of resistance R When these are connected
in parallel, the equivalent resistance is
X. When these will be connected in
series, then the equivalent resistance will be
A ( cdot X / n^{2} )
в. ( n^{2} X )
( c cdot x / n )
D. nx
12
1052For a metallic wire, the ratio ( frac{V}{i} ) (where,
( mathbf{V}= ) applied potential difference and ( mathbf{i}= )
current flowing
A. is independent of temperature
B. increases as the temperature rises
C. decreases as the temperature rises
D. increases or decreases as temperature rises depending upon the metal.
12
1053Which of the following methods does not help to minimize the error due to contact resistance in Wheatstone’s
meter bridge experiment:
A. The wire used must be uniform
B. The wire used must be non-uniform
c. Null point is obtained near the middle of the wire
D. Interchange the positions of unknown resistance (X) and known resistance(R)
12
1054Assertion: Material used in the
construction of a standard resistance is
constantan or manganin Reason : Temperature coefficients of constantan and Magnanin are very
small
A. Both (A) and (R) are true and
(R) is the correct explanation of (A)
B. Both (A) and (R) are true but (R) is not the correct explanation of ( (A) )
c. (A) is true but (R) is false
D. (A) is false but (R) is true
12
1055Four 2 ohm resistors are connected
together along the edges of a square. A 10V battery of negligible internal resistance is connected across a pair of
the diagonally opposite corners of the square. The power dissipated in the
circuit is
A. ( 100 mathrm{w} )
B. 50w
( c .25 w )
D. 20w
12
1056A potentiometer has a driving cell of negligible internal resistance. The balancing length of a Daniel cell is ( 5 mathrm{m} ) If the driving cell had internal resistance, the balancing length of the same Daniel cell would have been
A. More
B. Less
c. same
D. Cannot be said from the data
12
1057A metal wire of circular cross-section
has a resistance ( boldsymbol{R}_{1} ). The wire is now stretched without breaking so that its length is doubled and density is assumed to remain same. If the
resistance of the wire now becomes ( boldsymbol{R}_{2} )
then ( R_{2}: R_{1} ) is:
A .1:
B. 1: 2
( c cdot 4: )
D. 1: 4
12
1058esistance is connected across a uniform
wire of length ( 1 m ). The positive terminal of
another battery of e.m.f. ( 4 V ) and internal
resistance ( 1 Omega ) is joined to the point ( A ) as
shown in the figure. The ammeter shows
zero deflection when the jockey touches
the wire at the point ( C )
The length AC is equal to
( A cdot 2 / 3 m )
( 3.1 / 3 mathrm{m} )
( c cdot 3 / 5 m )
12
12
1059The current through the ( 8 Omega ) resistor is
( A cdot 4 A )
B. 2 A
c. zero
D. 2.5 A
12
1060A meter bridge is set-up as shown, to
determine an unknown resistance. ( boldsymbol{X} )
using a standard 10 ohm resistor. The
galvanometer shows null point when
tapping key is a ( 52 mathrm{cm} ) mark. The end-
corrections are ( 1 mathrm{cm} ) and ( 2 mathrm{cm} )
respectively for the ends ( A ) and ( B ). The
determined value of ( X ) is:
( mathbf{A} cdot 10.2 mathrm{ohm} )
B. 10.6 ohm
c. 10.8 ohm
D. 11.1 ohm
12
1061A heater is designed to operate with a power of ( 1000 W ) on a line of ( 100 V ). It is
connected in combination with
resistance of ( 10 Omega ) and a resistance ( R ) to
line of ( 100 mathrm{V} ). The value of ( mathrm{R} ) so the
entire circuit operates with a power of
( mathbf{6 2 5} boldsymbol{W} ) is
( A cdot 5 Omega )
В. ( 10 Omega )
( c .15 Omega )
D. 20Omega
12
1062An ideal battery of ( 4 V ) and resistance ( R ) are connected in series in the primary
circuit of a potentiometer of length ( 1 boldsymbol{m} ) and resistance ( 5 Omega . ) The value of ( R, ) to
given a potential difference of ( 5 m V )
( operatorname{across} 10 c m ) of potentiometer wire is:
( mathbf{A} cdot 490 Omega )
в. ( 480 Omega )
c. ( 395 Omega )
D. ( 495 Omega )
12
1063Find the value of ( n ) for carbon
A . 0.15
в. 0.3
( c .0 .9 )
D. 0.6
12
1064The value of ( I ) in the figure shown below
is
A . ( 19 A )
в. ( 21 A )
( c .8 A )
( D cdot 4 A )
12
1065A 50 V d.c power supply is used to charge a battery of eight lead
accumulators, each of emf ( 2 mathrm{V} ) and
internal resistance ( 1 / 8 Omega ). The charging current also runs a motor connected in
series with the battery. The resistance of the motor is ( 5 Omega ) and the steady current supply is 4 A. The chemical power stored in the battery is
( A cdot 64 mathrm{W} )
B. 96 ( w )
( c cdot 16 w )
D. 50 w
12
1066The potential difference between the terminals of an electric heater is ( 220 mathrm{V} )
and the current is 5A. What is the
resistance of the heater?
A . 22
B. 11
( c cdot 44 )
D. 1100
12
1067Match Column ( I ) with Column ( I I: )12
1068The resistance ( R ) of a conductor varies
with the temperature as shown in the
figure. If it is written as ( boldsymbol{R}_{1}=boldsymbol{R}_{0}(mathbf{1}+ )
( left.boldsymbol{alpha} boldsymbol{t}+boldsymbol{beta} boldsymbol{t}^{2}right) )
A ( cdot alpha ) and ( beta ) are both negative
B. ( alpha ) is positive and ( beta ) is negative
c. ( alpha ) and ( beta ) are both positive
D. ( alpha ) is negative and ( beta ) positive
12
1069Which of the following is true for electrical energy?
( mathbf{A} cdot E=P times t )
c. ( _{E}=frac{V^{2}}{R t} )
D. None of these
12
1070Which part of the curve shown in fig
represents the postitive resistane?
This question has multiple correct options
( mathbf{A} cdot A B )
B. ( B C )
( mathbf{c} cdot C D )
( mathbf{D} cdot D E )
12
1071A wire has resistance of 3.1 at ( 30 C ) and
resistance 4.5 at ( 100^{circ} C . ) The
temperature coefficient of resistance of the wire is
B. ( 0.0024^{circ} mathrm{C}^{-1} )
c. ( 0.0032^{circ} mathrm{C}^{-1} )
D. ( 0.0064^{circ} mathrm{C}^{-1} )
12
1072It is observed in a potentiometer
experiment that no current passes through the galvanometer across when
the terminals of a cell are connected
across a certain length of the potentiometer wire. On shuting the cell by a ( 2 Omega ) resistance, the balancing length is reduced to half. The internal resistance of the cell is :-
A . ( 4 Omega )
B. 2Omega
c. ( 1 Omega )
D. 8Omega
12
1073In the circuit shown, the readings of
ammeter and voltmeter are ( 4 A ) and
( 20 V ) respectively. The meters are non
ideal, then ( boldsymbol{R} ) is:
( A cdot 5 Omega )
B. greater than ( 5 Omega )
C. Less than ( 5 Omega )
D. between ( 4 Omega ) and ( 5 Omega )
12
1074Each capacitors has capacitance ( C ) in
Fig.
Find ( boldsymbol{C}_{boldsymbol{A} boldsymbol{B}} )
( A )
B. 2
( c cdot c / 2 )
D. 3C/2
12
1075State Ohm’s law. Suggest an
experiment to verify it and explain the
procedure.
12
1076Assertion
The kinetic energy of electrons in a metallic wire will increase, if the
temperature of the wire is increased
Reason
On increasing temperature, conductivity of metallic wire decreases
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
1077Which of the follwing does not belong to
the group formed by the others?
A. Iron
B. Tin
c. Glass
D. stee
12
1078A single battery is connected to three
resistances as shown in Figure.
This question has multiple correct options
A. The current through 7 ( Omega ) resistance is 4 A
B. The current through ( 3 Omega ) resistance is 4 A
c. The current through ( 6 Omega ) resistance is 2 A
D. The current through ( 7 Omega ) resistance is 0
12
1079Ten identical batteries each of emf 2 V
are connected in series to a ( 8 Omega ) resistor.
If the current in the circuit is 2 A, then
the internal resistance of each battery is
A . ( 0.2 Omega )
В. ( 0.3 Omega )
( c .0 .4 Omega )
D. ( 0.5 Omega )
E . ( 1 Omega )
12
1080The difference between the electrostatic
potential of the positive end the negative end of an electric cell is the of
the cell.
12
1081In the given circuit, the value of current
is
A . 12 ampere
B. 11 ampere
c. 0.5 ampere
D. zero
12
1082Figure (a) and figure (b) both are
showing the variation of resistivity ( (rho) )
with temperature (T) for some
materials. Identify the type of these
materials.
A. Conductor and semiconductor
B. Conductor and Insulator
c. Insulator and semiconductor
D. Both are conductors
12
1083This graph is for
A. Ohmic conductor
B. Non-ohmic conductor
C . Electrolytes
D. Diodes
12
1084Draw the diagram of induction coil and label the following:
a. Primary coil
b. Make and break arrangement.
12
1085A battery of emf ( 10 mathrm{V} ) and internal resistance ( 3 mathrm{W} ) is connected to a
resistor. If the current in the circuit is
( 0.5 mathrm{A}, ) what is the resistance of the
resistor? What is the terminal voltage of
the battery when the circuit is closed?
12
1086Choose the correct option
A. rubber rod becomes positive and fur becomes negative
B. both rod becomes positive
C. rubber rod becomes negative and fur becomes positive
D. both becomes neutral
12
1087When there is an electric current
through a conducting wire along its length then an electric field must exist
A. inside the wire but normal to it
B. inside the wire but parallel to it it
c. outside the wire but normal to it
D. outside the wire but parallel to it
12
1088Four concentric spherical shell is ( A, B, C ) AND ( D ) has radius ( a, 2 a, 3 a ) and
( 4 a ) shell ( B ) and ( D ) has charge ( +q ) and ( -q )
The shell ( ^{prime} C^{prime} ) is earthed. Find ( V_{A}-V_{C} )
A ( cdot frac{k q}{2 a} )
в. ( frac{k q}{3 a} )
( c cdot frac{k q}{4 a} )
D. ( frac{k q}{6 a} )
12
1089The Kirchhoff’s first ( operatorname{law}left(sum i=0right) ) and second law ( left(sum i R=sum Eright), ) where the symbols have their usual meanings, are respectively based on
A. conservation of charge, conservation of energy
B. Conservation of charge, conservation of momentum
c. conservation of energy, conservation of charge
D. conservation of momentum, conservation of charge
12
1090The charge flowing through a resistor ( boldsymbol{R} )
varies with time ( t ) as ( Q=3 t-6 t^{2} . ) The
heat produced in ( boldsymbol{R} ) till the current in it becomes zero is
A ( cdot frac{3 R}{4} )
в. ( frac{3 R}{2} )
c. ( frac{4 R}{2} )
D. ( frac{9 R}{2} )
12
1091( boldsymbol{L} )
If length of potentiometer wire is ( frac{-}{2} ) and
resistance is ( x ) then value of unknown
emf ( boldsymbol{E} ) is:
A ( cdot frac{2 E_{0} x ell}{r_{1}+x} )
B. ( frac{2 E_{0} x ell}{2 r_{1}+x} )
c. ( frac{4 E_{0} x ell}{2 r_{1}+x} )
D. ( frac{4 E_{0} x ell}{r_{1}+x} )
12
1092In the given circuit resistors ( A ) and ( B )
made of same metal are of the same
length but A is thicker than B which of
the two ammeters will show a higher
12
1093Find the emf and internal resistance of
the equivalent cell between ( A ) and ( B ). put
[
begin{array}{l}
varepsilon_{1}=3 mathrm{V}, r_{1}=2 Omega varepsilon_{2}=2 V, r_{2}=1 Omega \
varepsilon_{3}=6 V, r_{3}=1 Omega
end{array}
]
12
1094The potentiometer wire 10 m long and
20 ohm resistance is connected to a
3 volt emf battery and a 10 ohm
resistance. The value of potential
gradient in volt( / boldsymbol{m} ) of the wire will be
A . 1.0
B. 0.2
c. ( 0 . )
D. 0.02
12
1095Primary circuit of potentiometer is as shown in the diagram. Find potential
drop across the wire AB.
12
1096Write the principle on which the
working of a metre bridge is based. In an experiment on meter bridge, student obtains the balance point at the point ( J )
such that ( A J=40 c m ), as shown in
figure. The values of ( boldsymbol{R} ) and ( boldsymbol{X} ) are both
doubled and then interchanged. Find the new position of the balance point. If the galvanometer and battery are also interchanged how will the position of
balance point be affected
12
1097A current is induced in a coil by
electromagnetic induction.
A. Only when coil moves in the magnetic field
B. Only when a magnetic is moved into a coil
C. Only when the coil and magnet move with respect to each other
D. None of the above
12
1098In the circuit shown in fig., all wires
have equal resistance ( mathrm{R}(=5 Omega) ). The
equivalent resistance between ( A ) and ( B ) :
A ( cdot 10 / 7 Omega )
B. 15/4 ( Omega )
( c .7 Omega )
D. 3 ( Omega )
12
1099( frac{=}{frac{i}{L}} )12
1100Find the terminal voltage across ( boldsymbol{E}_{1} ) and
( boldsymbol{E}_{2} ) in fig :
A. ( 3.6 V, 7.8 V )
B. ( 2.4 V, 7.8 V )
c. ( 3.6 V, 10 V )
D. ( 2.4 V, 10.2 V )
12
1101The resultant of two resistances
connected in parallel is 2 oh ( m ) and when
connected in series, the resultant
becomes 9 oh ( m ). The values of the
resistance are:
A. 7 ohm, 2 ohm
B. 11ohm, 7ohm
c. 4.5 and 8 ohm
D. 3ohm, 6ohm
12
1102Which of the following statements
is/are correct for potentiometer circuit?
A. Sensitivity doesn’t depend on the length of the potentiometer wire.
B. Sensitivity is inversely proportional to potential difference applied across the potentiometer wire.
C. Accuracy of potentiometer can be increased, only by increasing length of the wire.
D. Range is independent of potential difference applied across the potentiometer wire.
12
1103Each resistance shown in figure is ( 2 Omega )
The equivalent resistance between ( boldsymbol{A} )
and ( B ) is
( A cdot 2 S )
в. 4 ?
( c cdot 85 )
0.1
12
1104The fixed resistance is called
A. rheostat
B. resistor
( c cdot k e y )
D. switch
12
1105If the resistance of a conductor is ( 5 Omega ) at
( 50^{circ} mathrm{C} & 7 Omega ) at ( 100^{circ} mathrm{C}, ) then mean
temperature coefficient of resistance (of material) is
A ( cdot 0.013 /^{circ} mathrm{C} )
B. 0.004/ ( ^{circ} mathrm{C} )
c. ( 0.006 /^{circ} mathrm{C} )
D. ( 0.008 /^{circ} mathrm{C} )
12
1106( sum_{k=1}^{k} )12
1107The internal resistance of a primary cell
is 4 Omega. It generates a current of ( 0.2 mathrm{A} ) in
an external resistance of ( 21 Omega ). The rate
of chemical energy consumed in providing the current is
A ( cdot 0.42 mathrm{J} mathrm{s}^{-} 1 )
B. 0.84 J ( s^{-1} )
c. ( 1 J s^{-1} )
D. 5 J ( s^{-1} )
12
1108On increasing the resistance in a
circuit, the current in it :
A. decreases
B. increases
c. remains unchanged
D. nothing can be said
12
1109What do you understand by the internal resistance of a cell? The potential difference of a cell becomes ( 1.8 mathrm{V} ) when
( 0.5 A ) current is drown and when ( 1.0 A )
current is drawn, it becomes ( 1.6 mathrm{V} ). Find
the internal resistance of the cell and
its e.m.f.
12
1110A bulb of ( 22 Omega ) is producing light when connected to ( 220 mathrm{V} ) supply. What is the electric power of the bulb.
A. 2200 watt
B. 1000 watt
c. 22 watt
D. 2 watt
12
1111Twelve cells, each having an e.m.f of ( mathrm{E} )
volt are connected in series and are
kept in a closed box. Some of these cells
are wrongly connected with positive and negative terminals reversed. This 12 cell battery is connected in series with
an ammeter, an external resistance ( mathrm{R} )
ohms and a two-cell battery (two cells of the same type used earlier, connected perfectly in series). The current in the
circuit when the 12 -cell battery and 2 cell battery aid each other is ( 3 A ) and is
2A when they oppose each other. Then the number of cells in 12-cells
battery that are connected wrongly is:
A . 14
B. 3
( c cdot 2 )
D.
12
1112A current I is passing through a wire having two sections ( mathrm{P} ) and ( mathrm{Q} ) of uniform diameters d and ( d / 2 ) respectively if the mean drift velocity of electrons in section ( mathrm{P} ) and ( mathrm{Q} ) is denoted by and
respectively then.
12
1113What are the factors on which
resistance of a conductor depends?
12
1114Two wires of equal length, one of aluminium and the other of copper have
the same resistance. Which of the two
wires is lighter? Hence explain why aluminium wires are preferred for
overhead power cables. ( left(rho_{A I}=2.63 timesright. )
( 10^{-8} Omega m, rho_{C u}=1.72 times 10^{-8} Omega m )
Relative density of ( A I=2.7, ) of ( C u=8.9 . )
12
1115The resistance of the series comb of two
resistance is S. When they are joined in parallel the total resistance is P. If ( mathrm{S}=mathrm{nP} ) then the minimum possible value of ( n ) is:
( A cdot 4 )
B. 3
( c cdot 2 )
( D )
12
1116Find power dissipated in ( 4 Omega ) resistor:
( A cdot 12 w )
B. 16 ( w )
( c cdot 4 w )
( 0.6 mathrm{w} )
12
1117What is the current in branch ( A B ) of the
circuit shown?
A . ( 1.5 A )
в. ( 2 A )
c. ( 1.33 A )
D
12
1118In a potentiometer arrangement, a cell of emf ( 1.25 mathrm{V} ) gives a balance point at ( 35.0 mathrm{cm} ) length of the wire. If the cell is replaced by another cell and the balance point shifts to ( 63.0 mathrm{cm}, ) what is the emf
of the second cell?
12
1119Figure shows three circular arcs, each
of radius ( mathrm{R} ) and total charge as
indicated. The net electric potential at
the centre of curvature is?
A ( cdot frac{Q}{2 pi varepsilon_{R}} )
B・ ( frac{Q}{3 pi varepsilon_{R}} )
c. ( frac{2 Q}{pi_{c e R} R_{R}} )
D. ( frac{Q}{pi varepsilon R} )
12
1120Every atom makes one free electron in
copper. If 1.1 ampere current is flowing in the wire of copper having ( 1 mathrm{mm} ) diameter, then the drift velocity
(approx) will be (density of copper ( =9 times )
( 10^{3} k g / m^{3} ) and atomic weight of copper
( =mathbf{6 3}) )
A. ( 0.1 m m / s )
B. ( 0.2 mathrm{mm} / mathrm{s} )
( mathbf{c} cdot 0.3 m m / s )
D. ( 0.2 c m / s )
12
aissipatea is nignest? (Neglect the
internal resistance of the power supply)
( A )
B.
( c )
( D )
12
1122In the circuit shown in fig., the potential
difference between the points ( C ) and ( D ) is balanced against ( 40 mathrm{cm} ) length of
potentiometer wire of total length 100 ( mathrm{cm} . ) In order to balance the potential
difference between the points D and ( E ) the jockey should be pressed on
potentiometer wire at a distance of
A . ( 16 mathrm{cm} )
B. 32 ( mathrm{cm} )
( c .56 mathrm{cm} )
D. ( 80 mathrm{cm} )
12
1123Current passing through a coil of resistance R decreases uniformly as shown in the figure. If total amount of
charge q is passing through the coil
during a time interval ( t_{0} ) then what will
be the total amount of heat generated through it?
A ( cdot frac{3}{4} frac{q^{2} R}{t_{0}} )
в. ( frac{4}{3} frac{q^{2} R}{t_{0}} )
c. ( frac{q^{2}}{t_{R}} )
D. ( frac{q^{2} R^{2}}{t^{2}} )
12
1124Electric current arises from the flow of
charged particles. Now
This question has multiple correct options
A. In metals it is dominant due to flow of electrons
B. In semiconductors it is jointly due to flow of holes and electrons
C. In electrolytes it is due to flow of negative ions only
D. In discharge tubes containing gases at low pressure it is due to flow of positive ions only
12
1125Resistance ( R, 2 R, 3 R ldots N R ) if, ( N R ldots ) are connected in parallel. Their resultant resistance will be
A.
B. R/2
( c cdot 0 )
D. ( infty )
12
1126Calculate total resistance, total current
and p.d across ( 7 Omega ) resistor
12
1127A short-circuited coil is placed in a time-varying magnetic field. Electrical power is dissipated due to the current induced in the coil. If the number of
turns were to be quadrupled and the wire radius halved, the electrical power
dissipated would be:
A. Halved
B. The same
c. Doubled
12
1128Four resistances of each 20 ohm are
connected to form a square ( boldsymbol{A}, boldsymbol{B}, boldsymbol{C}, boldsymbol{D} )
The resultant resistance between the
corners ( A C ) and the resistance between
( A B ) are:
A ( .40 Omega, 15 Omega )
B. ( 15 Omega, 40 Omega )
c. ( 15 Omega, 20 Omega )
D. ( 20 Omega, 15 Omega )
12
1129A common device which can supply
small electric current continuously for a sufficient time
12
1130The resistance between ( A ) and ( B ) is
A ( cdot frac{288}{56} Omega )
В. ( 12 Omega )
( c cdot frac{8}{3} Omega )
D. ( frac{9}{4} Omega )
12
1131n the circuit shown in the figure, the
( A cdot 0.8 A )
B. 1.2 A
( c cdot 2 A )
D. ( 0.4 mathrm{A} )
12
1132The resistance can be increased by :
A. decreasing the area
B. decreasing the length
c. either (A) or (B)
D. none of these
12
1133Name the principle on which metre bridge is based.12
1134If a copper wire is stretched to make it ( 0.1 % ) longer, the ( % ) change in the resistance is
A . 0.3%
B. 0.2%
c. 0.1%
D . 0.02%
12
1135When a current of ( 2 mathrm{A} ) flows in a battery
from negative to positive terminal, the potential difference across it is 12 V. If a
current of 3 A flowing in the opposite direction produces a potential difference of ( 15 V ), the emf of the battery is?
A . ( 54 v )
B. ( 13.2 mathrm{V} )
c. ( 65 v )
D. ( 50 v )
12
1136Calculate the electric current in the
circuit shown.
A ( .1 .5 A )
в. ( 0.5 A )
( c .2 .5 A )
0.2
12
1137toppr
the following:
4
B.
( c )
( D )
12
1138Find out the total current flowing in the circuit as shown in above figure?
( A cdot 4 A )
B. 3A
c. ( 2 A )
D. ( frac{4}{3} )
( E )
12
1139Resistance of a electric heater is ( 20 Omega )
and it draws a current of 2A. Calculate
its power.
A. 0 (zero) ( w )
B. 20w
c. ( 40 mathrm{w} )
D. 80w
12
1140Each of the resistance in the network
shown in figure is equal to R. The
resistance between the terminals ( A ) and
B is
( A cdot R )
B. 5R
( c . ) 3R
( D cdot 6 r )
12
1141The internal resistance of a primary cell
is 4 ohm. It generates a current of 0.2 ampere in an external resistance of 2
ohm. The rate at which chemical energy
is consumed in providing the current is
A ( .0 .42 mathrm{J} / mathrm{s} )
B. 0.24 J/
( c cdot 5 J / s )
( D cdot 1 J / s )
12
1142Stopping Potential is:12
1143A steady current is set up in a metallic wire of non-uniform cross section. Then
the drift velocity is related to the area of ( operatorname{cross} operatorname{section}(A) ) as:
A. ( V_{d} propto A^{-1} )
B. ( V_{d} propto A )
( mathbf{C} cdot V_{d} propto A^{2} )
D. ( V_{d} ) is independent of ( A )
12
1144The following table gives the current ( i )
through two devices for several values
of potential difference ( V ) of Device 1 Device ( 2(text { SI Units }) )
( begin{array}{llll}text { Device } & text { Device } & text { Device } & text { Device } \ 1 & 1 & 2 & 2 \ V & I & V & I \ 2 & 4.5 & 2 & 1.5 \ 3 & 6.75 & 3 & 2.2 \ 4 & 9 & 4 & 2.8end{array} )
A. Device 1 is ohmic, device 2 is non ohmic
B. Device 1 is non ohmic, device 2 is ohmic
c. Both are non ohmic.
D. Both are ohmic
12
1145State Kirchhoff’s laws of electrical
circuits with the help of suitable circuit diagram. Write formula of zero deflection of Wheatstone bridge.
12
1146In which direction does current flow in
an electric circuit ? Also, write the SI unit of electric current.
12
1147A circuit is shown below.lf ( A ) is an ideal
ammeter, B an ideal Battery of voltae ( V )
and ( C ) an ideal voltmeter, what will be
( A )
в. 2 R
( c cdot frac{R}{2} )
( D )
12
1148quantıties for the pictured circult. What is the current flowing through the
resistor ( 3 ? )
Battery Terminal Voltage ( quad 16.0 mathrm{v} )
Ammeter 2 Reading ( 7.0 mathrm{A} )
( A cdot 8.0 A )
B. 13.0 A
( c cdot 7.0 A )
D. 16.0 A
E. 6.0
12
1149For a cell terminal potential difference is ( 2.2 mathrm{V} ) when circuit is open and
reduces to ( 1.8 mathrm{V} ) when cell is
connected to a resistance of ( boldsymbol{R}=mathbf{5} Omega )
then determine internal resistance of
cell is :-
A ( cdot frac{10}{9} Omega )
в. ( frac{9}{10} Omega )
c. ( frac{11}{9} Omega )
D. ( frac{5}{9} Omega )
12
1150A storage battery has e.m.f. 15 volt and internal resistance 0.05 ohm. Its terminal
voltage when it is delivering 10 ampere is:
A. 30 volt
B. 1.00 volt
c. 14.5 volt
D. 15.5 volt
12
1151The resistance of a wire of length 100
( mathrm{cm} ) and ( 7 times 10^{-3} mathrm{cm} ) radius is 6 ohm. Its
specific resistance is
( mathbf{A} cdot 924 times 10^{-8} Omega c m )
В. ( 92.4 times 10^{-8} Omega c m )
c. ( 900 times 10^{-8} Omega c m )
D. ( 224 times 10^{-8} Omega c m )
12
1152Three identical bulbs are connected in
parallel with a battery. The current drawn from the battery is ( 6 A ). If one of
the bulbs gets fused, what will be the total current drawn from the battery?
( mathbf{A} cdot 6 A )
в. ( 2 A )
( c .4 A )
D. ( 8 A )
12
1153Which of the following best describe the
current?
A. the rate of flow of charged particles through a conducting medium
B. only present when there is no voltage
C. the flow of a conductor through charged particles
D. faster than the speed of light
E. the random movement of electrons from atom to
atom
12
1154A copper wire of resistance ( R ) is cut in
to ten parts of equal length. Two pieces each are joined in series and then five such combinations are joined in parallel. The new combination will have
a resistance
A. ( R )
в. ( frac{R}{4} )
c. ( frac{R}{5} )
D. ( frac{R}{25} )
12
1155The figure shows a meter bridge with
null deflection in the galvanometer. The value of unknown resistance R is?
( mathbf{A} cdot 158 Omega )
B . ( 151.67 Omega )
c. ( 128.65 Omega )
D. ( 130 Omega )
12
1156S.I. unit of electric current is:
A. ampere
B. volt
D. coulomb
12
1157A current flows in a wire of circular
cross section with the free electrons
travelling with drift velocity ( bar{V} ). If an equal current flows in a wire of same material and twice the radius, the new
drift velocity is:
( mathbf{A} cdot bar{V} )
B. ( frac{vec{v}}{2} )
c. ( frac{vec{v}}{4} )
D. 2 ( bar{V} )
12
1158A wire of resistance ( 10.0 Omega ) is stretched
and increases its length by ( 20 % ). Its resistance then would be: ( neglect any
change in volume or resistivity
A . ( 10.0 Omega )
B. ( 12.0 Omega )
c. ( 14.4 Omega )
D. ( 10.2 Omega )
12
1159toppr
salvaluilicio ” 2
and a variable voltage source V. The
correct circuit to carry out the
experiment is
( A )
B.
( c )
( D )
12
1160At a constant voltage the heat developed in a uniform wire varies
inversely as the length of the wire used.
12
1161For ohmic conductor the drift velocity ( boldsymbol{v}_{boldsymbol{d}} )
and the electric field applied across it are related as :
( mathbf{A} cdot v_{d} propto sqrt{E} )
B ( cdot v_{d} propto E^{2} )
c. ( v_{d} propto E )
D. ( v_{d} propto frac{1}{E} )
12
1162Specific resistance of all metals is
mostly affected by
A. volume
B. pressure
c. temperature
D. magnetic field
12
1163State Ohm’s Law using a suitable experiment,explain the terms involved and draw its graphical representation.12
1164Derive the relation between the
resistances of the arms of a

Wheatstone bridge in its balance condition. Write its two applications.

12
1165Find the radius of the wire of length
( 25 m ) needed to prepare a coil of
resistence ( 25 Omega ) (Resistivity of material of wire is ( left.3.142 times 10^{-7} Omega mright) )
12
1166Carbon resistors are of two types:
A. composition type resistor and film type resistor
B. rheostat and film type resistor
C. rheostat and variable resistor
D. composition type resistor and rheostat
12
1167An infinite non-conducting sheet of
charge has a surface charge density of ( 10^{-7} C / m^{2} . ) The separation between two
equipotential surfaces near the sheet whose potential difference by ( 5 V ) is
A ( .0 .88 mathrm{cm} )
В. ( 08.8 m m )
c. ( 0.88 m )
D. ( 5 times 10^{-7} m )
12
1168The emf of the battery in a thermocouple is doubled. The rate of
heat generation at one of the junctions will
A. remains unchanged
B. becomes half
c. becomes double
D. becomes four times
12
1169Which of the following theories could not explain completely the behaviour of conductors, insulators, and
semiconductors.
A. energy band theory
B. free electron theory
c. valence electron theory
D. None
12
1170Find the current flows through a copper wire of length ( 0.2 mathrm{m}, ) area of crosssection ( 1 m m^{2}, ) when connected to a
battery of ( 4 mathrm{V} ). Given that electron
mobility is ( 4.5 times 10^{-6} m^{2} s^{-1} ) and
charge on an electron is ( 1.6 times 10^{-19} C )
The number density of electron in copper wire is ( 8.5 times 10^{2} 8 m^{3} )
12
1171Current ( ^{prime} i^{prime} ) coming from the battery and ammeter reading are
A ( cdot frac{3}{8} A, frac{1}{8} A )
в. ( frac{1}{8} A, frac{1}{8} A )
c. ( 2 A, frac{2}{3} )
‘ ( 2 A, frac{1}{8} )
12
1172What is the non linear ( V-I ) relation in
a pn Junction in forward bias?
A. ( I=I_{s} e^{V / V_{T}} )
В . ( I=I_{s}left(e^{V / V_{T}}-1right) )
C ( . I=I_{s}left(1-e^{V / V_{T}}right) )
( D )
12
1173A galvanometer (coil resistance ( 99 Omega) )
is converted into a ammeter using a
shunt of ( 1 Omega ) and connected as shown in
the figure ( ( i ) ). The ammeter reads ( 3 A )
The same galvanometer is converted
into a voltmeter by connecting a
resistance of ( 101 Omega ) in series. This
voltmeter is connected as shown in
figure ( ( i i ) ). Its reading is found to be ( 4 / 5 )
of the full scale reading. Find the internal resistance ( r ) of the cell (in
ohms)
12
1174A current ( i ) is flowing through the wire of
diameter ( d ) having drift velocity of
electrons ( v_{d} ) in it. What will be new drift
velocity when diameter of wire is made ( frac{boldsymbol{d}}{boldsymbol{4}} )
( mathbf{A} cdot 4 V_{d} )
в. ( frac{V_{d}}{4} )
( mathbf{c} cdot 16 V_{d} )
D. ( frac{V_{d}}{16} )
12
1175mass m carrying charge ( q . ) The bead
freely move on the smooth fixed ring
placed on a smooth horizontal plane. In
the same plane a charge ( +Q ) has also
been fixed as shown. The potential at
the point ( boldsymbol{P} ) due to ( +boldsymbol{Q} ) is ( boldsymbol{V} ). The velocity
with which the bead should projected
from the point ( P ) so that is can complete
a circle should be greater than
A ( cdot sqrt{frac{6 q V}{m}} )
B. ( 4 sqrt{frac{q V}{m}} )
c. ( sqrt{frac{3 q V}{m}} )
D. ( sqrt{frac{7 q V}{2 m}} )
12
1176What is the S.I. unit of electrical power?
A. watts
B. joules
c. volts
D. ampere
12
1177A resistance of ( 2 Omega ) is connected across
one gap of a metrebridge ( the length of the wire is ( 100 mathrm{cm} ) ) and an unknown
resistance, greater than ( 2 Omega, ) is connected across the other gap. When
these resistance’s are interchanged, the balance point shifts by ( 20 mathrm{cm} ) Neglecting any corrections, the unknown resistance is:
A . ( 3 Omega )
B. ( 4 Omega )
( c .5 Omega )
D. ( 6 Omega )
12
1178Copper and Germanium are cooled from
room temperature to ( 100 K . ) Then the
resistance of
A. Germanium decreases, Copper increases
B. Germanium decreases, Copper decreases
c. Germanium increases, Copper decreases
D. Germanium increases, Copper increases
12
1179( n^{prime} ) cells, each of emf ( ^{prime} e^{prime} ) and internal
resistance ‘ ( r^{prime} ) are joined in series to
form a row.’ ( m^{prime} ) such rows are
connected in parallel to form a battery of ( boldsymbol{N}=boldsymbol{m} boldsymbol{n} ) cells. This battery is
connected to an external resistance ( ^{prime} boldsymbol{R}^{prime} )
What is the emf of this battery and how much is its internal resistance?
12
1180Six resistors of each 2 ohm are
connected as shown in the figure. The
resultant resistance between ( A ) and ( B )
is.
( mathbf{A} cdot 4 Omega )
B. ( 2 Omega )
( c cdot 1 Omega )
D. ( 10 Omega )
12
1181What is called the rate of doing work in an electric circuit?
A. Power
B. Energy
c. current
D. voltage
12
1182Kirchhoff’s law of junction, ( sum I=0 ), is based on
A. Conservation of energy
B. conservation of charge
c. conservation of energy as well as charge
D. conservation of momentum
12
1183( frac{k}{L} )12
1184Twenty four cells each of emf ( 1.5 mathrm{V} ) and internal resistance 0.5 ohms are to be
connected to a 3 ohm resistance. For
maximum current through this resistance the number of rows and
number of columns that you connect
these cells is?
A. 12 cells in series 2 rows in parallel
B. 8 cells in series 3 rows in parallel
c. 4 cells in series 6 rows in parallel
D. 6 cells in series 4 rows in parallel
12
1185When 1 coulomb of charge flows
through any cross-section of a
conductor in 1 second, the electric current through it is said to be 1
ampere.
A. True
B. False
12
1186A carbon resistance has a following
colour code. What is the value of the
resistance?
A ( .1 .64 M Omega pm 5 % )
B. ( 530 k Omega pm 5 % )
( c cdot 64 k Omega pm 10 % )
D. ( 5.3 M Omega pm 5 % )
12
1187If three wires of equal resistance are given then number of combinations they can be made to give difference resistance is
A . 4
B. 3
( c .5 )
D.
12
1188A battery has six cells in series and each cell has an electromagnetic force ( 1.5 V ) and internal resistance ( 1 Omega . ) If
an external load of resistance ( 24 Omega ) is
connected to it. The potential drop across the load is
A. ( 7.2 V )
B. ( 0.3 V )
c. ( 6.8 V )
D. ( 0.4 V )
12
1189A potentiometer wire is ( 10 mathrm{m} ) long and a potential difference of ( 6 V ) is maintained between its ends.The emf of a cell which
balances against a length of ( 180 mathrm{cm} ) of the potentiometer wire is:
A . 1.8 ( v )
B. 1.1 ( v )
c. ( 1.08 mathrm{v} )
D. 1.2
12
1190Define electric current. What is its ( S I )
unit?
12
1191Find the cost of operating an electric toaster for ( 2 h r s, ) if it draws a current of
( 8 A ) on a ( 110 V ) circuit. The cost of
electric energy is ( boldsymbol{R} boldsymbol{s} boldsymbol{2} . boldsymbol{5} / boldsymbol{k} boldsymbol{W} boldsymbol{h} )
A. Rs 4.40
в. Rs 6
c. ( R s 8.20 )
D. Rs 2.20
12
1192Estimate the average drift speed of
conduction electrons in a copper wire of
cross-sectional area ( 2.5 times 10^{-7} m^{2} )
carrying a current of 2.7 A. Assume the density of conduction electrons to be
( 9 times 10^{28} m^{-3} )
12
1193How much electrical energy is transferred per second by a ( 4 V ; 0.5 A ) lamp?
A. 20 J/S
B. 2 J/S
( c cdot 6.8 mathrm{J} / mathrm{s} )
D. 4.8 J/S
12
1194Find out the value of ( mathrm{E} ) in the circuit
shown in figure.
A ( .+14 V )
B . ( -14 V )
( c .-7 V )
( D cdot+7 V )
12
1195A light bulb uses energy at a rate of 25.0 Watts. If the current through light bulb is 2.00 A. What is the resistance of the
bulb?
A. 6.25 ohms
B. 12.5 ohms
c. 0.0800 ohms
D. 50.0 ohms
E. 100.0 ohms
12
1196For the network shown in the figure the
value of the current i is
A ( cdot frac{18 V}{5} )
B. ( frac{5 v}{9} )
( c cdot frac{9 V}{355} )
D. ( frac{5 V}{18} )
12
1197The principle involved in potentiometer
is
A. variation of current with variati wire on in the diameter of the potentiometer
B. similar to the principle of Wheatstone bridge
C. variation of resistance with temperature
D. both (a) and (b)
12
1198The current ( I ) drawn from the ( 5 V ) source
in the given circuit will be :
A. 0.33 A
B. ( 0.5 mathrm{A} )
c. ( 0.67 mathrm{A} )
D. 0.17 A
12
1199Using three wires of resistances 1 ohm, 2ohm and 3 ohm, number of different possible values of resistances are:
A. 6
в. 4
( c cdot 10 )
D. 8
12
1200According to Joule’s law, if the potential difference across a conductor of
resistivity ( rho ) remains constant, then the
heat produced in the conductor is
proprotional to
( A cdot frac{1}{rho} )
в. ( frac{1}{sqrt{rho}} )
( mathbf{c} cdot rho^{2} )
D.
12
any branch of the base of the square pyramid shown. Assume resistance of each branch is R
A. ( frac{7 R}{15} )
в. ( frac{8 R}{15} )
c. ( frac{R}{2} )
D. None of these
12
1202Find equivalent capacitance between ( A )
and B.
12
1203Three 2 resistors, ( A, B, ) and ( C, ) are connected as shown below.Each of them
dissipates and can stand a maximum
power of ( 18 mathrm{W} ) without melting. Find the maximum current that can
flow through the three resistors.
12
1204If ( n ) is the number density of free electrons in a metallic wire, then the
resistance is proportional to
A ( . n )
B ( cdot n^{2} )
( c cdot frac{1}{n} )
D. ( frac{1}{n^{2}} )
12
1205The mass of 3 copper gain is 1:3:5 and length 5: 3: 1 then the resistance?12
1206A copper wire with a cross-section area
of ( 2 times 10^{-6} m^{2} ) has a free electon
density equal to ( 5 times 10^{22} / c m^{2} . ) If this
wire carries a current of ( 16 A ), the drift
velocity of the electron is?
( mathbf{A} cdot 1 m / s )
в. ( 0.1 m / s )
c. ( 0.01 m / s )
D. ( 0.001 m / s )
E. ( 0.00001 mathrm{m} / mathrm{s} )
12
1207For a heater rated at ( 4.4 mathrm{kW} ; 220 mathrm{V} ) Calculate the energy consumed by the heater in 4 hours?
A. ( 12 mathrm{kWh} )
B. 17.6 kWh
( c cdot ) okwh
D. ( 4.4 mathrm{kWh} )
12
1208In a circuit shown, the average power dissipated in the resistor is (assume
diode to be ideal)
A ( cdot frac{E_{0}^{2}}{2 R} )
в. ( frac{E_{0}^{2}}{4 R} )
c. ( frac{E_{0}^{2}}{R} )
D. zero
12
1209Electrical resistivity of a given metallic
wire depends upon:
A. its length
B. its thickness
c. its shape
D. nature of the material
12
1210The electrical resistivity of a conducting wire is ( mathrm{K} ). If its length and area of crosssection are doubled then the new
resistivity of the wire will be :
( A cdot K )
в. 2 к
c. ( K / 2 )
D. ( K / 4 )
12
1211A heater coil connected to a ( 220 mathrm{V} ) has a
resistance of 150 oh ( m ). How long will it
take for this coil to heat ( 1 k g ) of water
from ( 20^{0} C ) to ( 60^{0} C ), assuming that all
heat is taken up by water.
A . 210 sec
B. 420 sec
( c .520 mathrm{sec} )
D. None of these
12
1212R
55 S2
my
W
M
5. Shown in the figure is a meter
bridge set up with null deflection
in the galvanometer. The value
of the unknown resistor R is
(a) 1102
(b) 5522
(c) 13.7522
(d) 2202
20 cm
552
(AIEEE 2008)
12
1213A piece of resistance wire has
resistance of ( 4 Omega . ) Its diameter is
doubled. Now its resistance will be :
( mathbf{A} cdot 8 Omega )
B. 2Omega
c. ( 4 Omega )
D. 12
12
1214A conducting material obeys ohm’s law
when
A. The resistivity of material is independent of it magnitude and direction of the applied electric field.
B. The resistivity of material is dependent on the magnitude of the applied electric field
C. When the resistance is dependent on the magnitude of the applied electric field
D. All
12
1215In the circuit shown, the ammeter
reading is zero. Then, the value of the
resistance R is:
( A cdot 50 Omega )
B. ( 100 Omega )
c. ( 200 Omega )
0.4005
12
1216The resistance of a wire at temperature
( 30^{circ} mathrm{C} ) is found to be ( 10 Omega . ) Now to
increase the resistance by ( 10 %, ) the temperature of the wire must be ( The temperature coefficient of resistance of the material of the wire is ( 0.002^{circ} mathrm{C}^{-1} )
and reference temperature is ( 0^{circ} C ) ).
A ( cdot 35^{circ} mathrm{C} )
B . ( 36^{circ} mathrm{C} )
( mathbf{c} cdot 33^{circ} C )
D. ( 83^{circ} mathrm{C} )
12
1217In a Wheatstone’s bridge, there resistances ( P, Q ) and ( R ) connected in the three arms and the fourth arm is
formed by two resistances ( S_{1} ) and ( S_{2} ) connected in parallel. The condition for bridge to be balanced will be :
( ^{text {A } cdot frac{P}{Q}}=frac{R}{S_{1}+S_{2}} )
в. ( frac{P}{Q}=frac{2 R}{S_{1}+S_{2}} )
c. ( frac{P}{Q}=frac{Rleft(S_{1}+S_{2}right)}{S_{1} S_{2}} )
D. ( frac{P}{Q}=frac{Rleft(S_{1}+S_{2}right)}{2 S_{1} S_{2}} )
12
1218In a Wheatstone’s bridge, there resistances ( mathbf{P}, boldsymbol{O} ) and ( mathbf{R} ) connected in
the three arms and the fourth arm is
formed by two resistances ( mathbf{S}_{1} ) and ( mathbf{S}_{mathbf{2}} )
connected in parallel. The condition for
bridge to be balanced will be
A ( cdot frac{P}{O}=frac{R}{S_{1}+S_{2}} )
B. ( frac{P}{O}=frac{2 R}{S_{1}+S_{2}} )
c. ( frac{P}{O}=frac{Rleft(S_{1}+S_{2}right)}{S_{1} S_{2}} )
D. ( frac{P}{O}=frac{Rleft(S_{1}+S_{2}right)}{2 S_{1} S_{2}} )
12
1219With the help of a circuit diagram
describe the method to find the value of
an unknown resistance using meter bridge arrangement.
12
1220The resistor of resistance ( boldsymbol{R} ) is
connected between the terminals of a
cell of emf ( boldsymbol{E} ) and internal resistance ( boldsymbol{r} )
The current ( I ) through the circuit is :
A ( cdot frac{E}{R r} )
в. ( frac{E}{R+r} )
c. ( frac{R+r}{E} )
D. ( frac{E}{R}+r )
12
1221A and ( B ) are two conductors carrying a
current ( i ) in the same direction, ( x ) and ( y )
are two electron beams moving in the
same direction. There will be:
A. Repulsion between ( A ) and ( B ), attraction between ( x ) and
( y )
B. Attraction between ( A ) and ( B ), repulsion between ( x ) and
( y )
C. Repulsion between ( A ) and ( B ), and also ( x ) and ( y )
D. Attraction between ( A ) and ( B ), and also ( x ) and ( y )
12
1222Two diametrically opposite points of a metal ring are connected to terminals of
the left gap of meter bridge. In the right gap, resistance of ( 15 Omega ) is introduced. If
the null point is obtained at a distance
of ( 40 mathrm{cm} ) from the left end, find
resistance of the wire that is bent in the
shape of the ring.
12
1223On which conservation principle is
Kirchoff’s Second Law of electrical
networks based?
12
1224For a given circuit, it is observed that
the current ( I ) is independent of the
value of the resistance ( R_{6} ). Then, the
resistance values must satisfy
A ( cdot R_{2} R_{3}=R_{1} R_{4} )
в. ( R_{3} R_{4} R_{6}=R_{2} R_{1} R_{5} )
c. ( frac{1}{R_{3}+R_{4}}=frac{1}{R_{5}}+frac{1}{R_{6}}-frac{1}{R_{1}+R_{2}} )
D. ( R_{3} R_{1}=R_{2} R_{4}=R_{5} R_{6} )
12
1225Suppose a current carrying wire has a cross-sectional area that gradually
become smaller along the wire has the shape of a very long cone as shown in
figure:
A. Electric current is different in different portions of wire
B. Electric field at point ( A ) is same as that of point ( B )
C. Drift speed of electrons at point ( A ) is lesser than that of at point ( B )
D. Drift speed of electrons at point ( A ) is same as that of at point ( B )
12
1226A current of ( 5 A ) is passing through a metallic wire of cross-sectional area
( 4 times 10^{-6} m^{2} . ) If the density of charge
carriers of the wire is ( 5 times 10^{26} m^{-3}, ) the
drift velocity of the electrons will be :
A. ( 1 times 10^{2} mathrm{ms}^{-1} )
В. ( 1.56 times 10^{-2} mathrm{ms}^{-1} )
c. ( 1.56 times 10^{-3} m s^{-1} )
D. ( 1 times 10^{-2} mathrm{ms}^{-1} )
12
1227The resistance of a wire is 50 ohm. Then
the graph between ( log V ) and ( log I ) is :-
A. straight line
B. parabola
c. hyperbola
D. circle
12
1228State the two Kirchhoff’s laws. Explain briefly, how these rules are justified?12
1229A potential difference of ( 20 mathrm{V} ) is needed to make a current of ( 0.05 mathrm{A} ) flow through a resistor. What potential difference is needed to make a current of ( 300 mathrm{mA} )
flow through the same resistor?
A. ( 60 v )
B. 1200
c. ( 40 v )
D. 150V
12
1230How much energy in kilowatt hour is consumed in operating ten 50 watt bulbs for 10 hours per day in a month ( (30 ) days)
A . 1500
B. 5000
c. 15
D. 150
12
1231Find out the current through ( 2 Omega ) resistor
in the circuit shown in figure.
( A, 2,5 A )
B. 5 A
c. 1.25 A
D. 2 A
12
1232Two resistances ( boldsymbol{R}_{1}=(mathbf{1 0 0}+mathbf{3}) ) ohms and ( R_{2}=(200+4) ) ohms are connected in series. What is their
equivalent resistance?
12
1233A battery of ( 9 V ) is connected in series
with resistors of ( 0.5,0.3,0.4,0.2, ) and 12
How much current would now through the 0.4 resistors?
( mathbf{A} cdot 22.5 A )
B . ( 2.25 A )
c. ( 0.67 A )
D. ( 6.7 A )
12
1234A constant potential difference is applied between the ends of the wire. If
the length of the wire is elongated 4 times, then the drift velocity of electrons will be:
A. increases 4 times
B. decreases 4 times
c. increases 2 times
D. decreases 2 times
12
1235A resistance of ( 4 Omega ) and a wire of length
( 5 m ) and resistance ( 5 Omega ) are joined in
series and connected to a cell of e.m,f,
( mathbf{1 0} V ) and internal resistance ( 1 Omega . A )
Parallel combination of two identical
cells is balanced across ( 300 mathrm{cm} ) of the
wire. the e.m.f. ( boldsymbol{E} ) each cell is then:
A ( .1 .5 ~ V )
в. ( 3.0 V )
( c .0 .67 V )
0.1 .33
12
1236A wire has a non-uniform cross-section
as shown in figure. A steady current
flows through it. The drift speed of
electrons at points ( mathrm{P} ) and ( mathrm{Q} ) is ( v_{P} ) and ( v_{Q} )
then?
( mathbf{A} cdot v_{P}=v_{Q} )
в. ( v_{P}v_{Q} )
D. Data is insufficient
12
1237Mark the correct statement:
A. Resistivity is the measure of a materials ability to oppose the flow of current
B. Unit of resistivity is Ohm meter
C. Resistivity is constant for a particular range of temperature
D. All
12
1238In the figure, current through the ( 3 Omega )
resistor is 0.8 ampere, the potential
drop through ( 4 Omega ) resistor is
A ( .9 .6 ~ V )
B . ( 2.6 V )
c. ( 4.8 V )
D. ( 1.2 V )
12
1239and that of an ideal Voltmeter is
infinite. A Voltmeter and an Ammeter
are connected in the circuit as shown.
Resistance of ammeter is say ( boldsymbol{R} / mathbf{1} mathbf{0} ) and
that of Voltmeter is ( 10 R ). Then:
A. Percentage error in the reading of Ammeter (compared to that measured, if both Ammeter and voltmeter were ideal) is ( 1.0 % )
B. Percentage error in the reading of voltmeter is ( 10.0 % )
c. Both (a) and
(b) are correct
D. Both
(a) and
(b) are wrong
12
1240One Volt is equal to –
A. 1 Joule
B. 1 Newton/Coulomb
c. 1 Joule/Coulomb
D. 1 Coulomb/Newton
12
1241When resistor are connected in series
what remains same.?
A. current
B. Voltage
c. Resistance
D. power
12
1242You have three equal resistances r. The maximum possible number of different resistance values that you can offer is
( A cdot 4 )
B. 5
( c cdot 6 )
( D .7 )
12
1243In figure. the galvanometer shows no deflection. What is the resistance ( X ? )
( A cdot 7 Omega )
в. ( 14 Omega )
( c .21 Omega )
D. ( 28 Omega )
12
1244To get maximum current through a resistance of ( 2.5 Omega ), one can use ( mathrm{m} ) rows
of cells, each row having n cells. The internal resistance of each cell is ( 0.5 Omega )
What are the value of ( n ) and ( m ), if the
total number of cells is ( 45 ? )
A ( . m=3, n=15 )
в. ( m=5, n=9 )
c. ( m=9, n=5 )
D. ( m=15, n=3 )
12
1245In which of the following substances the resistance decreases with the increase
in temperature?
A. carbon
B. constantan
c. copper
D. Silver
12
1246f ( i=0.25 ) amp. in the fig the value of ( R )
is :-
( A cdot 48 Omega )
в. ( 12 Omega )
c. ( 120 Omega )
D. ( 42 Omega )
12
1247Which of the following material has lowest resistivity?
A. Manganin
B. Copper
c. constantan
D. Silver
12
1248The following graph was plotted
between ( mathrm{V} ) and ( mathrm{I} ) values. What would be
the values of ( V / I ) ratios when the
potential difference is ( 0.5 mathrm{V} ) and ( 1 mathrm{V} ) ?
12
1249Assertion
For good conductors, the ( boldsymbol{I}-boldsymbol{V} ) graph is
a perfect straight line inclined to current axis.
Reason
By Ohm’s law, voltage across the ends of a conductor is directly proportional to the resistance of the conductor.
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
1250In the network shown in figure, the
equivalent resistance between points ( X ) and Y will be
( A )
в. ( frac{r}{2} )
( c cdot 2 r )
D. ( frac{r}{3} )
12
1251In the figure a long uniform
potentiometer wire ( A B ) is having a
length. The null points for the two
primary cells of emfs ( varepsilon_{1} ) and ( varepsilon_{2} )
connected in the manner shown are
obtained at a distance of ( 120 mathrm{cm} ) and
( 300 c m ) from the end ( A . ) Find (i) ( varepsilon_{1} / varepsilon_{2} )
and (ii) position of null point for the cell
( varepsilon_{1} )
How is the sensitivity of a
potentiometer increased?
12
1252A ( 2 V ) battery, a ( 990 Omega ) resistor and a
potentiometer of ( 2 m ) length,all are connected in series of the resistance of
potentiometer wire is ( 10 Omega ), then the potential gradient of the potentiometer wire is
A ( cdot 0.05 V m^{-1} )
B ( .0 .5 V m^{-1} )
c. ( 0.01 V m^{-1} )
D. ( 0.001 V m^{-1} )
12
1253Resistivity of a given conductor depends upon
A. temperature
B. length of conductor
c. area of cross section
D. shape of the conductor
12
1254A Wheatstone bridge consisting of four ( operatorname{arms} ) of resistances ( P, Q, R, S ) is most
sensitive when :
A. All the resistance are equal
B. All the resistance are unequal
c. The resistances ( P ) and ( Q ) are equal but ( R>>P ) and ( S>>Q )
D. The resistance ( P ) and ( Q ) are equal but ( R<<P ) and ( S< ) ( <Q )
12
1255Two identical heater wires are first
connected in series and then in parallel with a source of electricity. The ratio of heat produced in the two cases is
A. 2:
B. 1: 2
( c cdot 4: )
( D cdot 1: 4 )
12
1256In effective resistance between ( C ) and ( B )
is
A . ( 2 Omega )
B. 3Omega
c. ( 1 Omega )
D.
12
1257In the given circuit diagram, the value
of resistance ( X ) in ohm when the bridge
is balanced will be –
4
B.
c. 10
D. 12
12
1258Two batteries of different emf and
internal resistances connected in series
with each other and with an external
load resistor. The current is 3.0 A. When
the polarity of one battery is reversed, the current becomes 1.0 A. The ratio of
the emf of the two batteries is :
A .2 .5: 1 )
в. 2: 1
c. 3: 2
D. 1: 1
12
1259Two cells having emf’s of ( 10 V ) and ( 8 V )
and internal resistance of ( 1 Omega ) (each) are
connected as shown with an external
resistance of ( 8 Omega ). Find the current
flowing through the circuit.
12
1260An electric current of 2.0 A passes
through a wire of resistance 25 Omega. How much heat (in joule) will be developed in 1 minute?
( A cdot 6 )
B. 6000
( c .50 )
D. 10
12
1261There are four resistors of 12 ohm each.
Which of the following values is/are possible by their combinations (series and / or parallel)? This question has multiple correct options
( mathbf{A} cdot 9 ) ohm
B. 16 ohm
c. 12 ohm
D. 30 ohm
12
1262All the edges of a block with parallel faces are unequal. Its longest edge is twice its shortest edge. The ratio of the maximum to minimum resistance
between parallel faces is
A .2
B. 4
( c cdot 8 )
D. indeterminate unless the length of the third edge is specified
12
1263The equivalent resistance ( R ) of three
resistors ( R_{1}, R_{2} ) and ( R_{3} ) joined in
parallel is
A ( cdot R=R_{1}+R_{2}+R_{3} )
B . ( R=1 / R_{1}+1 / R_{2}+1 / R_{3} )
( ^{mathbf{C}} cdot_{R}=frac{R_{1} R_{2} R_{3}}{R_{1} R_{2}+R_{2} R_{3}+R_{3} R_{1}} )
D. ( R=1 /left(R_{1}+R_{2}+R_{3}right) )
12
12646. In the experiment of Ohm’s law. When potential difference
10.0 V is applied, current measured is 1.00 A. If length
of wire of found to be 10.0 cm, and diameter of wire is
2.50 mm, then the maximum permissible error in
resistivity will be
(a) 1.8%
(b) 10.2%
(c) 3.8%
(d) 5.75%
12
1265An electric motor driven pump fills an overhead tank placed at a height of 20
( mathrm{m} ) from the ground-level sump at a rate
of 20,000 litre water per hour.The motor has an operating resistance of ( 22 Omega ) and is connected across a ( 220 mathrm{V} ) source.The
efficiency of this motor is (Useg ( = )
( left.9.8 m / s^{2}right) )
( mathbf{A} cdot 12.5 % )
B. ( 73.5 % )
c. ( 49.5 % )
D. ( 22.5 % )
12
1266A ( 3 h p ) motors requires ( 2.4 k w ) to drive it;
A . ( 90 % )
B. 75%
c. ( 60 % )
D. 50%
12
1267In the circuit above, ( boldsymbol{R}_{1}=mathbf{2} boldsymbol{R}_{3} ) and
( R_{3}=2 R_{2} . ) If the source voltage is ( V_{1} )
find the power dissipated in ( boldsymbol{R}_{mathbf{1}} )
( mathbf{A} cdot frac{left(V_{1}right)^{2}}{7 R_{2}} )
B. ( frac{left(V_{1}right)^{2}}{14 R_{2}} )
c. ( frac{left(3 V_{1}right)^{2}}{7 R_{2}} )
D. ( frac{left(V_{1}right)^{2}}{49 R_{2}} )
E ( cdot frac{left(3 V_{1}right)^{2}}{49 R_{2}} )
12
1268When a resistor of ( 2 Omega ) is connected
across the terminals of a battery a current of ( 2 A ) is found to flow. When a
second resistor of ( 8 Omega ) is connected in
series with the first, the current is
reduced to ( 1 A . ) The emf and internal
resistance of the battery are
A ( .12 %, 4 Omega )
B. 10V, 2Omega
( c cdot 16 v, 6 Omega )
D. 16V, 4Omega
12
1269The current ( I ) through a rod of a certain metallic oxide is given by ( boldsymbol{I}=mathbf{0 . 2} boldsymbol{V}^{mathbf{5} / mathbf{2}} )
where ( V ) is the potential difference across it. The rod is connected in series
with a resistance to a ( 6 V ) battery of negligible internal resistance. What value should the series resistance have
so that the power dissipated in the rod is twice that dissipated in the resistance?
12
1270A resistor has resistance R. When the
potential difference across the resistor
is ( V ), the current in
the resistor is I. The power dissipated in
the resistor is P. Work W is done when
charge ( Q ) flows through the resistor. What is not a valid relationship between
these variables?
( mathbf{A} cdot I=frac{P}{V} )
В ( cdot Q=frac{W}{V} )
C ( cdot R=frac{P}{I^{2}} )
D ( cdot R=frac{V}{P} )
12
1271Calculate the number of electrons
constitute one coulomb of charge.
12
1272Table 1
Table – 2
(a) Potential difference across battery
(b) Potential difference across battery
(c) Power is supplied by battery
( (r) 14 V )
(d) Power is consumed by battery
( (s) 9 V )
none
( A cdot a-p ; b-p ; c-q ; d-r )
B. ( a-q ; b-q ; c-r ; d-s )
( c cdot a-r, b-t, c-p, d-q )
( D cdot a-r ; b-r ; c-s ; d-t )
12
1273When ( 5 V ) potential difference is applied across a wire length ( 0.1 m ), the drift
speed of electron is ( 2.5 times 10^{-4} m s^{-1} . ) If
the electron density in the wire is 8 ( times 10^{28} m^{-3}, ) the resistivity of the material is close to
A ( cdot 1.6 times 10^{-8} Omega mathrm{m} )
В. ( 1.6 times 10^{-7} Omega mathrm{m} )
c. ( 1.6 times 10^{-6} Omega mathrm{m} )
D. ( 1.6 times 10^{-5} Omega ) m
12
1274n Fig. circuit section, ( A B ) absorbs energy at a rate of ( 50 % ) W when a current ( i=1.0 ) A passes through it in the indicated direction. If device X does not
have internal resistance, what is its
emf?
A. 24 v
в. 48 v
( c cdot 32 v )
D. 12 V
12
1275Calculate the equivalent resistance for
each arrangement.
Series arrangement
12
1276A voltmeter and an ammeter are joined
in series to an ideal cell, giving readings ( mathrm{V} ) and ( mathrm{A} ) respectively. If ( mathrm{a} )
resistance equal to the resistance of the ammeter if now joined in parallel to
the ammeter
This question has multiple correct options
A. V will no change
B. V will increase slightly
c. A will become exactly half of its initial vale
D. A will become slightly more than half of its initial value
12
1277(a) Three resistors ( 2 Omega, 4 Omega ) and ( 5 Omega ) are
combined in parallel. What is the total resistance of the combination?
(b) If the combination is connected to a
battery of emf ( 20 mathrm{V} ) and negligible internal resistance, determine the
current through each resistor, and the total current drawn from the battery.
12
1278The dimensional formula of mobility is
( mathbf{A} cdot M^{-1} L^{1} T^{2} A^{mathbf{1}} )
B. ( M^{1} L^{0} T^{-2} A^{-1} )
c. ( M^{1} L^{-1} T^{-2} A^{-1} )
D. ( M^{-1} L^{0} T^{2} A^{1} )
12
1279Resistance of a resistor at temperature
( t^{0} boldsymbol{C} ) is ( boldsymbol{R}_{t}=boldsymbol{R}_{0}left(mathbf{1}+boldsymbol{alpha} boldsymbol{t}+boldsymbol{beta} boldsymbol{t}^{2}right) . ) Here ( boldsymbol{R}_{0} )
is the resistance at ( 0^{0} C . ) The
temperature coefficient of resistance at
temperature ( t^{0} C ) is
A ( cdot frac{left(1+alpha t+beta t^{2}right)}{alpha+2 beta t} )
в. ( alpha+2 beta t )
c. ( frac{alpha+2 beta t}{left(1+alpha t+beta t^{2}right)} )
D. ( frac{alpha+2 beta t}{2left(1+alpha t+beta t^{2}right)} )
12
1280Potentiometer measures potential
more accurately because
A. it measures potential in the open circuit.
B. it uses sensitive galvanometer for null deflection.
C. it uses high resistance potentiometer wire.
D. it measures potential in the closed circuit.
12
1281Find the emf and internal resistance of
the equivalent cell between ( A ) and ( B ). put
[
begin{array}{l}
varepsilon_{1}=3 mathrm{V}, r_{1}=2 Omega varepsilon_{2}=2 V, r_{2}=1 Omega \
varepsilon_{3}=6 V, r_{3}=1 Omega
end{array}
]
12
1282The potential at point ( B, C ) and ( D ) in the following circuit will be
A . ( 12 vee, 10 vee, 6 v )
B. ( 11 vee, 9 vee, 6 v )
c. ( 11 vee, 9 vee, ) o ( v )
D. ( 12 vee, 10 vee, ) o ( v )
12
1283A current of ( 1 A ) flows through a copper
wire. The number of electrons passing through any cross-section of the wire in
1.6 ( sec ) is (charge of a electrons ( =1.6 times )
( left.10^{-19} Cright) )
( mathbf{A} cdot 10^{19} )
B. ( 10^{2} )
( c cdot 10^{25} )
D. ( 10^{28} )
12
1284Ohm’s law is true:
A. For metallic conductor at low temperature
B. For metallic conductor at high temperature
C. For electrolytes, when current passes through them
D. For diode when current flows
12
1285The current voltage graph for a given
metallic wire at two
different temperatures ( T_{1} ) and ( T_{2} ) are
shown in given figure, which of the relation is correct from the following?
A ( cdot T_{2}>T_{1} )
в. ( T_{1}>T_{2} )
c. ( T_{1}=T_{2} )
D. none of these
12
1286The temperature coefficient resistivity of a material is ( 0.0004 / K . ) When the
temperature of the material is
increased by ( 50^{circ} C, ) its resistivity increases by ( 2 times 10^{-8} ) ohm – meter
The initial resistivity of the material of the resistance
A . ( 50 times 10^{-8} )
B. ( 90 times 10^{-8} )
c. ( 100 times 10^{-8} )
D. ( 200 times 10^{-8} )
12
1287Find out the value of I in the circuit
shown in figure.
( A cdot 5 A )
в. 2.5
( c cdot 10 A )
( D cdot 4 A )
12
1288Heater of an electric kettle is made of a
wire of length L and diameter d. It takes
4 minutes to raise the temperature of ( 0.5 mathrm{kg} ) water by ( 40 mathrm{K} . ) This heater is replaced by a new heater having two wires of the same material, each of
length L and diameter 2d. The way these wires are connected is given in the options. How much time in minutes will it take to raise the temperature of the
same amount of water by ( 40 mathrm{K} ? ) This question has multiple correct options
A. 4 if wires are in parallel
B. 2 if wires are in series
c. 1 if wires are in series
D. 0.5 if wires are in parallel
12
1289In the circuit shown below, all the
resistances are equal, each equal to ( mathrm{R} )
The equivalent resistance
between points ( A ) and ( C ) is :
( A )
8. 4 R
( c cdot R / 2 )
D. None of the above
12
1290( 1 m A= )12
1291The terminal voltage of a cell is equal to
A. potential across external resistance.
B. potential across internal resistance.
C . potential across sum of external resistance and internal resistance.
D. emf of cell.
12
1292In the circuit shown in figure. Current
through ( R_{1} ) is independent of
A ( . R_{2} )
в. ( R_{3} )
( c cdot R_{4} )
D. All of these
12
1293What do you mean by the sensitivity of potentiometer?12
1294After switch is closed, current drawn
from the battery is
( A cdot 6 A )
3.1 .54
( c .3 A )
0.44
12
1295A given resistor has the following colour scheme of the various strips on it:
Brown, black, green and silver. Its value in ohm is :
A ( cdot 1.0 times 10^{4} pm 10 % )
В. ( 1.0 times 10^{5} pm 10 % )
C. ( 1.0 times 10^{6} pm 10 % )
D. ( 1.0 times 10^{7} pm 10 % )
12
1296On interchanging the resistances, the balance point of a meter bridge shifts to
the left by ( 10 mathrm{cm} . ) The resistance of their series combination is ( 1 k Omega ). How much
was the resistance on the left slot
before interchanging the resistances?
A . ( 550 Omega )
в. ( 910 Omega )
( mathbf{c} .990 Omega )
D. ( 505 Omega )
12
1297When Cu and Ge are cooled to ( -150^{circ} mathrm{C} )
then resistance of ( mathrm{Cu} )…. and that of Ge
A. increases, increases
B. decrease, increases
c. decrease, decreases
D. increases, decreases
12
1298Potentiometer wire length is ( 10 m )
having a total resistance of ( 10 Omega ). If a
battery of emf 2 volts (of negligible internal resistance) and a rheostat are
connected to it them the potential
gradient is ( 20 m V / m ; ) find the resistance imparted through the rheostat
12
1299Two unknown resistrance ( X ) and ( Y ) are
connected to left and right gaps of a meter bridge and the balancing point is obtained at ( 80 mathrm{cm} ) from left. When a ( 10 Omega ) resistance is connected in paralle to ( x ) the balance point is ( 50 mathrm{cm} ) from left. The values of ( X ) and ( Y ) respectively are
( A cdot 40 Omega, 9 Omega )
B. 30Omega ,7.5Omega
c. ( 20 Omega, 6 Omega )
D. ( 10 Omega, 3 Omega )
12
1300Three resistors ( (2,5 text { and } 7 text { ohm }) ) are
wires as shown in the diagram
below. The equivalent resistance of this
combination (in ohm) is:
A ( cdot frac{59}{70} )
B. ( frac{70}{59} )
( c cdot frac{1}{14} )
D. 14
E. Cannot be determined without additional information
12
1301The potentiometer wire AB shown in the figure is ( 40 mathrm{cm} ) long. Where should the
free end of the galvanometer be connected on AB so that the
galvanometer may show zero deflection?
12
1302In the given circuit the cells have zero
internal resistance. The currents (in
Amperes) passing through resistance
( R_{1}, ) and ( R_{2} ) respectively, are ( _{-}–1 )
A .2,2
B. 0,1
c. 1,2
D. 0.5,0
12
1303Four resistors, ( 100 Omega, 200 Omega, 300 Omega, ) and
( 400 Omega ) are connected to form four sides
of a square. The resistors can be connected in any order. What is the maximum possible equivalent resistance across the diagonal of the square?
A ( .210 Omega )
в. 240Omega
( mathbf{c} .300 Omega )
D. 250Omega
12
1304The mobility of free electrons (charge =e, mass = m and-relaxation
time ( tau ) ) in a metal is proportional to:
A ( cdot frac{e}{m} tau )
в. ( frac{m}{e} tau )
( c cdot frac{e}{m tau} )
D. ( frac{m}{e tau} )
12
1305Four resistance ( 5 Omega, 10 Omega, 15 Omega ) and an unknown ( X Omega ) are connected in series
so as to form Wheatsones network.
Determine the unknown resistance ( boldsymbol{X} )
if the network is balance with these
numerical values of resistances.
12
1306Murugan measured the electric current
What unit should he use?
12
1307A battery has four cells in parallel, each has an e.m.f ( 1.5 V ) and internal
resistance ( 0.8 Omega . ) The current delivered
by it to a load of ( 2.8 Omega ) is
A. ( 0.2 A )
B. 0.4A
c. ( 0.5 mathrm{A} )
D. ( 0.6 A )
12
1308The current I in the circuit shown below
is
( mathbf{A} )
( B cdot frac{1}{15} A )
( c cdot frac{1}{10} A )
( D cdot frac{1}{2} )
12
1309A torch bulb rated ( 4.5 mathrm{W}, 1.5 mathrm{V} ) is
nnected as in figure. The emf of the ell needed to make the bulb glow at ntensity i
12
1310The given image is a symbol of12
1311Derive the condition for balance of a
Wheatstone’s bridge using Kirchhoff’s rules.
12
1312The ( n ) rows each contaning in cells in
series are joined in parallel. Maximum current is taken from this combination
across an external resistance of ( 3 Omega ). If
the total number of cells used is 24 and
internal resistance of each cell is ( 0.5 Omega )
then
A. ( m=8, n=3 )
в. ( m=6, n=4 )
c. ( m=12, n=2 )
D. ( m=2, n=12 )
12
1313Find out the total current flowing in the circuit as shown in above figure?
( A cdot 4 A )
B. 3A
c. ( 2 A )
D. ( frac{4}{3} )
( E )
12
1314Two resistance thermometers are
made, one of the platinum wire and the other of germanium wire. The resistance of both the thermometers
are equal at room temperatures. Now the two resistance wires are connected
to a battery. The two resistance wire
are heated to ( 100^{circ} mathrm{C} ). The potential drop
in the two resistance is measured.
Which of the following statements is
correct?
A. The potential drop across the platinum wire is equal to the potential drop across the germanium wire
B. The potential drop across platinum wire is greater than that across germanium
C. The potential drop across the platinum wire is less than that across germanium
D. The nature of the potential drop can be ascertained unless the magnitude of the current is known
12
1315In the following circuit, the ( 1 Omega ) resistor dissipates power P. If the resistor is
replaced by ( 9 Omega ). the power dissipated in
it is
( A )
B. 3P
( c cdot 9 P )
D. P/3
12
1316The resistance of a wire is 5 ohm at ( 50^{circ} )
( mathrm{C} ) and 6 ohm at ( 100^{circ} mathrm{C} ). The resistance of
the wire at ( 0^{circ} mathrm{C} ) will be:
( A cdot 2 ) ohm
B. 1 ohm
c. 4 ohm
D. 3 ohm
12
1317Two long parallel wires carrying currents ( 2.5 mathrm{A} ) and I A in the same
direction (directed Into the plane of the paper) are held ( mathrm{M} mathrm{P} ) and ( mathrm{Q} ) respectively such that they are perpendicular to the
plane of the paper. The points ( P ) and ( Q ) are located at a distance of ( 5 mathrm{m} ) and 2
( mathrm{m}, ) respectively, from a collinear point ( mathrm{R} ) as shown in figure. An electron moving with a velocity of ( 4 times 10^{5} m s^{-1} ) along
the positive ( X ) -direction experiences a
force of magnitude ( 3.2 times 10^{-20} mathrm{N} ) at the
point ( R ) The current lin wire Q is
( A cdot 1 A )
B. 2 A
( c cdot 3 A )
( D cdot 4 A )
12
1318Three ammeters ( A, B ) and ( C ) of
resistances ( boldsymbol{R}_{boldsymbol{A}}, boldsymbol{R}_{boldsymbol{B}} ) and ( boldsymbol{R}_{boldsymbol{C}} )
respectively are joined as shown. When
some potential difference is applied
across the terminals ( T_{1} ) and ( T_{2}, ) their
readings are ( I_{A}, I_{B} ) and ( I_{C} ) respectively
This question has multiple correct options
( mathbf{A} cdot I_{A}=I_{B} )
B ( cdot I_{A} R_{A}+I_{B} R_{B}=I_{C} R_{C} )
( mathbf{C} cdot frac{I_{A}}{I_{C}}=frac{R_{C}}{R_{A}} )
D. ( frac{I_{B}}{I_{C}}=frac{R_{C}}{R_{A}+R_{B}} )
12
1319Assertion
( overrightarrow{boldsymbol{E}}=boldsymbol{E}_{boldsymbol{x}} hat{boldsymbol{i}}+boldsymbol{E}_{boldsymbol{y}} hat{boldsymbol{j}}+boldsymbol{E}_{z} hat{boldsymbol{k}}, vec{nabla} times overrightarrow{boldsymbol{E}}=mathbf{0} )
Reason
( E_{x}, E_{y}, E_{z} ) is independent.
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
1320fixed resistors of resistance ( 2.0 Omega ) and
( 4.0 Omega ) connected in series with a ( 3.0 Omega )
resistor fitted with a sliding contact.
These are connected across a battery of
e.m.f ( 9.0 mathrm{V} ) and zero internal resistance,
as shown
What are the maximum and the
minimum output voltages of this
potential divider circuit?
A. maximum voltage/V : ( 4.0 ; ) minimum voltage ( / V: 2.0 )
B. maximum voltage/V : 5.0 ; minimum voltage/V : 2.0
C. maximum voltage/V : ( 9.0 ; ) minimum voltage ( / V: 0 )
D. maximum voltage/V : 9.0 ; minimum voltage/ ( V: 2.0 )
12
observation table are shown in figure.
1000
100
1.5
1
Which of the readings is inconsistent?
4
B. 1
( c cdot 2 )
2
12
1322Figure shows three resistor configurations ( R 1, R 2 ) and ( R 3 )
connected to ( 3 V ) battery. If the power
dissipated by the configuration ( boldsymbol{R} mathbf{1}, boldsymbol{R} mathbf{2} ) and ( R 3 ) is ( P 1, P 2 ) and ( P 3, ) respectively
then
A. ( P 1>P 2>P 3 )
в. ( P 1>P 3>P 2 )
c. ( P 2>P 1>P 3 )
D. ( P 3>P 2>P 1 )
12
1323f ( boldsymbol{E}=mathbf{1 2} ) volts, ( boldsymbol{X}=mathbf{9} Omega, ) then distance
of balance point ( P ) from end ( A ) is
A. 20 cm
B. 50 ( mathrm{cm} )
c. ( 70 mathrm{cm} )
D. Data insufficient
12
1324Draw the circuit and the graph of Ohm’s
Law.
12
1325( frac{2}{2} )12
1326Which of the following quantities do not change when an ohmic resistor connected to a battery is heated due to
the current?
A. drift speedd
B. resistivity
c. resistance
D. number of free electrons
12
1327The length of potentiometer wire is ( 10 mathrm{m} ) and is connected in series with an
accumulator. The e.m.f. of a cell
balances against ( 250 mathrm{cm} ) length of wire. If the length of potentiometer wire is increased by ( 1 mathrm{m} ), calculate the new balancing length of wire.
12
1328A brass disc and a carbon disc of same
radius are assembled alternatively to make a cylindrical conductor. The resistance of the cylinder is independent of the temperature. The ratio of thickness of the brass disc to
that of the carbon disc is ( alpha ) is
temperature coefficient of resistance ( & )
Neglect linear expansion
A ( cdot frac{alpha_{C} rho_{C}}{alpha_{B} rho_{B}} )
в. ( frac{alpha_{C} rho_{B}}{alpha_{B} rho_{C}} )
c. ( frac{alpha_{B} rho_{C}}{alpha_{C} rho_{B}} )
D. ( frac{alpha_{B} rho_{B}}{alpha_{C} rho_{C}} )
12
1329The potential difference between points ( A ) and ( B ) in the circuit shown in figure
is ( 16 mathrm{V} ). Then,
This question has multiple correct options
A. the current through the ( 2 Omega ) resistance is 3.5 A
B. the current through the ( 4 Omega ) resistance is 2.5 A
c. the current through the ( 3 Omega ) resistance is 1.5 A
D. the potential difference between the terminals of the V battery is 7 V
12
1330The circuit below shows six resistors in
a circuit with a voltage source
supplying a voltage, ( V )
Which table gives the correct voltage
drops across resistor 6 and resistor ( 3 ? )
A. Voltage Drop across Resistor 6 – Voltage Drop across Resistor ( 3, V / 6-V / 6 )
B. Voltage Drop across Resistor 6 – Voltage Drop across Resistor ( 3, V-V )
c. voltage Drop across Resistor 6 – voltage Drop across Resistor ( 3.3 V-V )
D. voltage Drop across Resistor 6 – Voltage Drop across Resistor ( 3, V / 3-V )
E : ” ge Drop across Resistor 6- Voltage Drop across ( operatorname{tor} 3, V-V / 3 )
12
1331Assertion: A current carrying wire
should be charged.
Reason: The current in a wire is due to
flow of free electrons in a definite
direction.
A. Both (A) and (R) are true and
(R) is the correct explanation of A
B. Both (A) and (R) are true but (R) is not the correct explanation of A
c. (A) is true but (R) is false
D. (A) is false but (R) is true
12
1332An accumulator of emf 2 Volt and
negligible internal resistance is
connected across a uniform wire of
length ( 10 mathrm{m} ) and resistance ( 30 Omega ). The
appropriate terminals of a cell of emf
( mathbf{1 . 5} V ) olt and internal resistance ( 1 Omega ) is
connected to one end of the wire, and
the other terminal of the cell is
connected through a sensitive galvanometer to a slider on the wire. If the length of the wire which is required to produce zero deflection of the galvanometer is ( frac{x}{2} m . ) Find ( x )
12
1333In copper, each atom releases one electron. If a current of ( 1.1 mathrm{A} ) is flowing in the copper wire of diameter 1mm then
the drift velocity of electrons, will a pproximately be (density of copper ( = ) ( 9 times 10^{3} mathrm{Kgm}^{-3} ) and its atomic weight
( =mathbf{6 3}) )
A. ( 10.3 mathrm{mm} / mathrm{s} )
B. ( 0.1 mathrm{mm} / mathrm{s} )
c. ( 0.2 mathrm{mm} / mathrm{s} )
D. ( 0.2 mathrm{cm} / mathrm{s} )
12
1334A potentiometer having a wire of ( 4 m ) length is connected to the terminals of a battery with a steady voltage. ( A )
leclanche cell has a null point at 1 m. If
the length of the potentiometer wire is increased by 1 m, the position of the null point is
( mathbf{A} cdot 1.5 m )
B. ( 1.25 mathrm{m} )
c. 10.05 m
D. ( 1.31 m )
12
1335(A) Write with the help of a diagram the principle of a potentionmeter.
(B) Using a potentionmeter how do you determine the internal resistance of a
cell?
12
1336The V-I graph for conductor at
temperatures ( T_{1} ) and ( T_{2} ) are shown in
the figure. ( left(T_{2}-T_{1}right) ) is proportional to
A ( . cos 2 theta )
B. ( sin 2 theta )
( c cdot cot 2 theta )
D. ( tan 2 theta )
12
1337Three resistances ( 2 Omega, 4 Omega, 5 Omega ) are combines in series and this
combination is connected to a battery
of ( 12 mathrm{V} ) emf and negligible internal resistance. The potential drop across these resistances are.
A . (5.45,4.36,2.18) V
B. (2.18,5.45,4.36) ( mathrm{v} )
c. (4.36,2.18,5.45) v
D. (2.18,4.36,5.45)( vee )
12
1338If same potential difference is applied across two resistances, more heat will
be produced in the large value of resistance.
12
1339Effective resistance between ( A ) and ( C )
is:
A . ( 2 Omega )
B. ( 6 Omega )
( c .9 Omega )
D. None
12
1340How will you represent a resistance of ( 4500 pm 10 % ) using color code?12
1341Two ideal batteries of emf ( V_{1} ) and ( V_{2} )
and three resistances ( R_{1}, R_{2} ) and ( R_{3} )
are connected as shown in the figure.
The current in resistance ( boldsymbol{R}_{2} ) would be
zero if
This question has multiple correct options
A. ( V_{1}=V_{2} ) and ( R_{1}=R_{2}=R_{3} )
B . ( V_{1}=V_{2} ) and ( R_{1}=2 R_{2}=R_{3} )
c. ( V_{1}=2 V_{2} ) and ( 2 R_{1}=2 R_{2}=R_{3} )
D. ( 2 V_{1}=V_{2} ) and ( 2 R_{1}=R_{2}=R_{3} )
12
1342The momentum acquired by all free electrons in a wire a length I when a
current of i amp starts to flow is
A ( cdot frac{m i l}{e} )
B. ( frac{m e l}{i} )
( c . m i l )
D. mie
12
1343If current ( I_{1}=3 A ) sinwt and ( I_{2}= )
4 Acos( omega t, ) then ( I_{3} ) is
A ( .5 A sin left(omega t+53^{circ}right) )
B. ( 5 A sin left(omega t+37^{circ}right) )
c. ( 5 A sin left(omega t+45^{circ}right) )
D. 5 Asin ( left(omega t+30^{circ}right) )
12
1344If the current passing through an electric bell is doubled, the heat produced will become
A. four times
B. double
c. one-fourth
D. half
12
1345Two cylindrical rod have area of cross-
section ( boldsymbol{A}_{mathbf{1}} boldsymbol{A}_{mathbf{2}} . ) If ( boldsymbol{A}_{mathbf{1}} ) is greater than ( boldsymbol{A}_{mathbf{2}} )
Then which of the following is correct?
A. The resistivity of the cylinder having area of crosssection ( A_{1} ) is higher than the cylinder of cross-section ( A_{2} )
B. The resistivity of the cylinder having area of crosssection ( A_{2} ) is higher than the cylinder of cross-section
( A_{1} )
C. The resistivity of the cylinder having area of crosssection ( A_{1} ) is same as the cylinder of cross-section ( A_{2} )
D. None of the above
12
1346A potentiometer wire of length ( L ) and
resistance ( 10 Omega ) is connected in series
with a battery of e.m.f. ( 2.5 % ) and a
resistance in its primary circuit. The null point corresponding to a cell of
e.m.f. ( 1 V ) is obtained at a distance ( L / 2 )
If the resistance in the primary circuit is doubled then the position of new null
point will be
( mathbf{A} cdot 0.4 L )
B. ( 0.5 L )
c. ( 0.6 L )
( mathbf{D} cdot 0.8 L )
12
1347Which of the statement is wrong:-
A. when all resistance are equal, then the sensitivity of wheatstone bridge is maximum.
B. when the galvanometer and the cell are interchanged, then the balancing of wheat stone bridge will be effected.
C. Kirchoff’s first law for the currents meeting at the Junctions in an electric circuit shows the conservation of charge.
D. Rheostat can be used as potential divider.
12
1348Draw labelled circuit diagram of a
potentiometer to compare emfs of two
cells.

Write the working formula (Derivation not required)

12
1349To get maximum current in resistance of ( 3 Omega, ) one can use ( n ) parallel rows of ( m )
cells each connected in series. If the
total no. of cells is 24 and the internal
resistance is 0.5 ohm then:
A. ( m=12, n=2 )
в. ( m=8, n=3 )
c. ( m=2, n=12 )
D. ( m=6, n=4 )
12
1350In the arrangement of resistances shown below. The effective resistance
between points ( A ) and ( B ) is
A . ( 20 Omega )
в. ( 30 Omega )
( c .90 Omega )
D. ( 110 Omega )
12
1351Take the potential of the point ( B ) in the
figure, to be zero.
(a) Find the potentials
at the points ( mathrm{C} ) and ( mathrm{D} ). (b) If a capacitor is
connected between ( mathrm{C} ) and ( mathrm{D} ), What charge
will appear on the capacitor?
12
1352Potential difference is measured in
joules.
A . True
B. False
12
1353The resistance of the meter bridge ( A B )
is given figure is 4 Omega. With a cell of emf
( varepsilon=0.5 V ) and rheostat resistance
( R h=2 Omega ) the null point is obtained at
some point ( J . ) When the cell is replaced
by another one of emf ( varepsilon=varepsilon_{2} ) the same
null point ( J ) is found for ( R_{h}=6 Omega ). The
emf ( varepsilon ) is
A ( .0 .6 ~ V )
B. ( 0.5 V )
c. ( 0.3 V )
D. ( 0.4 V )
12
1354A uniform electric field and a uniform
magnetic field are acting along the same direction in a certain region. If an projected along the direction of the fields with a certain velocity then :
A. its velocity will decrease
B. its velocity will increase.
c. it will turn towards right of direction of motion
D. it will turn towards left of direction of motion
12
1355A voltmeter having a resistance of ( 998 Omega ) is connected to a cell of emf ( 2 mathrm{V} ) and
internal resistance ( 2 Omega . ) The error in the
measurement of emf will be.
A ( cdot 4 times 10^{-1} mathrm{V} )
B . ( 2 times 10^{-3} mathrm{V} )
c. ( 4 times 10^{-3} v )
D. ( 2 times 10^{-1} mathrm{V} )
12
1356A current of ( 16 A ) is made to pass
through a conductor in which the
number density of free electrons is ( 4 x ) ( 10^{28} m^{-3} ) and its area of cross section
is ( 10^{-5} m^{2} . ) The average drift velocity of free electrons in the conductor is:
A ( .2 .5 times 10^{-4} mathrm{ms}^{-1} )
B . ( 3.2 times 10^{-4} mathrm{ms}^{-1} )
c. ( 6.4 times 10^{-4} mathrm{ms}^{-1} )
D. ( 1.6 times 10^{-4} mathrm{ms}^{-1} )
12
1357The Sl unit of resistance is :
A. Newton
B. ohm
c. watt
D. Joule
12
1358Green,blue, brown,gold are the color bands on resistors.Find its resistance?
A. ( 580 Omega )
в. ( 560 Omega )
( mathbf{c} cdot 480 Omega )
D. ( 58 Omega )
12
1359Five resistance are connected as shown
in figure. If total current flowing is ( 0.5 A )
then the potential difference ( boldsymbol{V}_{boldsymbol{A}}-boldsymbol{A}_{boldsymbol{B}} )
is:
( A cdot 8 V )
в. ( 6 V )
( c cdot 2 V )
D. ( 4 V )
12
1360Assertion
If the current of a lamp increases by ( 20 % ), the percentage increase in the illumination of the lamp is ( 40 % )
Reason
Illumination of the lamp is directly proportional to the square of the current through the lamp.
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
1361An electric iron draws a current of ( 15 A )
from a ( 220 V ) supply. What is the cost of using iron for 30 min everybody for 15 days if the cost of unit is 2 rupees?
( (1 u n i t=1 k W h) )
A . Rs 49.50
B. Rs 60
c. Rs 40
D. Rs 10
12
1362The current through the ( 10 Omega ) resistor
shown in figure is
( 4 cdot 0.1 )
B. ( 0.2 mathrm{A} )
( c cdot 0.3 mathrm{A} )
D. zer
12
1363An electric cell of e.m.f. E is connected
across a copper wire of diameter d and length I. The drift velocity of electrons in
the wire is ( v_{d} ). If the length of the wire is changed to 21, the new drift velocity of electrons in the copper wire will be
( mathbf{A} cdot v_{d} )
в. ( 2 v_{d} )
c. ( v_{d} / 2 )
D. ( v_{d} / 4 )
12
1364The diagram shows three capacitor with
their capacitances with breakdown
voltages.what should be the maximum
value of external emf of source such
that no capacitor breaks down:-
( A cdot frac{33}{2} v o l t )
B . ( frac{11}{3} ) volt
( c cdot frac{13}{3} v o l t )
D. ( frac{11}{2} ) volt
12
1365In a house, individual powers of two elements are ( \$ \$ 1001 mathrm{W} 11001 mathrm{W} \$ \$ . ) The effective power of their series combination will be :
A . ( 120 mathrm{W} )
B. ( 75 W )
( mathbf{c} .50 W )
D. ( 60 W )
12
1366The instantaneous values of alternating current and voltages in a circuit are given as
( mathrm{i}=frac{1}{sqrt{2}} sin (100 pi t) ) ampere
( mathrm{e}=frac{1}{sqrt{2}} sin (100 pi t+pi / 3) mathrm{volt} )
The average power in Watts consumed in the circuit is:
A ( frac{sqrt{3}}{4} )
B. ( frac{1}{2} )
( c cdot frac{1}{8} )
D. 4
12
1367The carbon resistor has three orange
bands. The maximum value of
resistance offered by the resistor will be
A . ( 39.6 k . Omega )
в. ( 49.6 k Omega )
( mathbf{c} .33 k Omega )
D. 26.4kOmega
12
1368The length of potentiometer wire is ( 10 mathrm{m} ) and is connected in series with an
accumulator. The e.m.f. of a cell balances against ( 250 mathrm{cm} ) length of wire. If the length of potentiometer wire is increased by ( 1 mathrm{m} ), calculate the new balancing length of wire.
A . 2.00
B . 2.25
c. 2.50
D. 2.75
12
1369The effective capacitance of
combination of equal capacitors between points ( A ) and ( B ) shown in figure
is :
( A )
B. ( 2 C )
( c cdot 3 c )
0.0
9
12
1370When a steady current of ( 1 A ) flows
through a copper wire, the number of electrons crossing any cross-section area of the wire in one second is
A ( cdot 6.25 times 10^{16} )
B . ( 6.25 times 10^{18} )
( mathbf{c} cdot 625 times 10^{18} )
D. ( 6.25 times 10^{20} )
12
1371Six lead-acid type of secondary cells each of emf ( 2.0 mathrm{V} ) and internal
resistance of 0.015 are joined in series to provide a supply to a resistance of
( 8.5 . ) What are the current drawn from the supply and it’s terminal voltage?
A. 11.8749
B. 12.8749
c. 13.1749
D. 10.5749
12
1372Three-point charges ( 1 mathrm{C}, 2 mathrm{C} ), and ( 3 mathrm{C} ) are
placed at the corners of an equilateral
triangle Of side ( 1 mathrm{m} ). The work required to
move these charges to the corners of a
smaller equilateral triangle Of side ( 0.5 mathrm{m} )
in two different ways as in fig.(A) and
(B)Calculate the work done
A ( cdot 9 times 10^{9} )
B ( .99 times 10^{9} )
( mathbf{c} cdot 89 times 10^{9} )
D ( .29 times 10^{9} )
12
1373toppr ( E )
( Q ) тур
Note: the rate-flow vectors are not drawn
to scale. Identify the case(es) in which the
effective current through the conductor is the highest.
( mathbf{A} )
[
begin{array}{l}
odot 5 mathrm{c} / mathrm{s} \
5 mathrm{c} / mathrm{s} longleftrightarrow
end{array}
]
в.
[
Leftrightarrow 9 mathrm{c} / mathrm{s}
]
[
1 mathrm{c} / mathrm{s} longleftrightarrow
]
( c )
[
begin{array}{l}
Leftrightarrow 7 mathrm{c} / mathrm{s} \
3 mathrm{c} / mathrm{s} longleftrightarrow(oplus)
end{array}
]
D
[
Leftrightarrow 1 mathrm{C} /
]
[
text { 9 C/s } longleftarrow
]
12
1374Current in circuit, which makes bulb
glow or heats up the wire, is:
A. motion of charges
B. motion of atoms
c. motion of molecules
D. none of the above
12
1375A cell of emf ( E ) is connected to a
resistance ( R_{1} ) for time ( t ) and the amount
of heat generated in it is ( H . ) If the
resistance ( R_{1} ) is replaced by another
resistance ( boldsymbol{R}_{2} ) and is connected to the
cell for the same time ( t, ) the amount of
heat generated in ( boldsymbol{R}_{2} ) is ( 4 boldsymbol{H} ). Then
internal resistance of the cell is:
A. ( frac{2 R_{1}+R_{2}}{2} )
в. ( sqrt{R_{1} R_{2}} times frac{2 sqrt{R_{2}}-sqrt{R_{1}}}{sqrt{R_{2}}-2 sqrt{R_{1}}} )
c. ( sqrt{R_{1} R_{2}} times frac{sqrt{R_{2}}-2 sqrt{R_{1}}}{2 sqrt{R_{2}}-sqrt{R_{1}}} )
D. ( sqrt{R_{1} R_{2}} times frac{sqrt{R_{2}}-sqrt{R_{1}}}{sqrt{R_{2}}+sqrt{R_{1}}} )
12
1376The resistors in parallel in the following
circuit are
12
1377The electrical resistance in ohms of a
certain thermometer varies with
temperature according to the approximate law:
( boldsymbol{R}=boldsymbol{R}_{boldsymbol{o}}left[mathbf{1}+boldsymbol{alpha}left(boldsymbol{T}-boldsymbol{T}_{boldsymbol{o}}right)right] )
The resistance is ( 101.6 Omega ) at the triple-
point of water ( 273.16 mathrm{K}, ) and ( 165.5 Omega ) at the normal melting point of lead (600.5
K). What is the temperature when the resistance is ( 123.4 Omega ? )
12
1378( mathbf{A} )
( 3 Omega ) resistor as shown in fig is dipped
in to a calorimeter containing ( boldsymbol{H}_{2} boldsymbol{O} ). the
thermal capacity of ( H_{2} O+ ) calorimeter is 2000 J/K. If the circuit is active for 15
minutes find the rise in temperature of
( boldsymbol{H}_{2} boldsymbol{O} )
A ( cdot 2.4^{circ} mathrm{C} )
В. ( 2.9^{circ} mathrm{C} )
( c cdot 3.4^{circ} C )
D. ( 1.9^{circ} mathrm{C} )
12
1379In a meter-bridge experiment with
resistance ( R_{1} ) in left gap and resistance
( X ) in right gap, null point is obtained at
( 40 mathrm{cm} ) from left end. With a resistance
( R_{2} ) in left gap and same resistance ( X ) in
right gap, null point is obtained at
( 50 mathrm{cm} ) from left end. Where will be null
point if ( boldsymbol{R}_{1} ) and ( boldsymbol{R}_{2} ) are put first in series
and then in parallel, in the left gap and
right gap still containing ( X ? )
12
1380Which among the following is the commercial unit of electric power?
A. volt
B. Watt
c. Ampere
D. Kwh
12
1381( mathbf{A} )
( 12 Omega ) resistance is cut into three equal parts and then connected in triangular form. Determine the equivalent resistance between two ends of any side
of the triangle.
12
1382An ideal voltmeter is connected in Fig.
The current in circuit is
( A, 2 A )
B. 2.5
c. infinity
D. zero
12
1383Two resistances are connected in the
two gaps of a metre bridge. The balance point is ( 20 mathrm{cm} ) from the zero end. When a resistance ( 15 Omega ) is connected in series with the smaller of two resistances, the
null point shifts to ( 40 mathrm{cm} . ) The smaller of
the two resistances has the value.
( A cdot 8 Omega )
B. ( 9 Omega )
( c .10 Omega )
D. 12Omega
12
1384Assertion
Electric conduction in gases is possible
at normal pressure.
Reason
The electric conduction in gases
depends only upon the potential difference between the electrodes.
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
1385A point charge ( q ) is brought from infinity(slowly so that the heat developed in the shell is negligible) and is placed at the centre of a conducting
neutral spherical shell of inner radius a and outer radius ( b ), then work done by
external agent is:
( A cdot O )
B. ( frac{k q^{2}}{2 b} )
c. ( frac{k q^{2}}{2 b}-frac{k q^{2}}{2 a} )
D. ( frac{k q^{2}}{2 a}-frac{k q^{2}}{2 b} )
12
1386In the potentiometer arrangement shown in figure, null point is obtained
at length ( l )
Table Table – 2
(a) If ( E_{1} ) is increased
(p) ( l ) should increase
(b) If ( mathrm{R} ) is increased
(q) ( l ) should
decrease
(c) If ( E_{2} ) is increased
(r) ( l ) should
remain the same to again get the null point
A. a ( -q, b-q, c-p )
( c cdot a-p, b-p, c-r )
D. a – q, b-p, c-p
12
1387At room temperature, copper has free
electron density of ( 8.4 times 10^{28} m^{-3} . ) The
electron drift velocity in a copper conductor of cross-sectional area of
( 10^{-6} m^{2} ) and carrying a current of 5.4
( mathbf{A}, mathbf{w} ) ill be
A ( cdot 4 m s^{-1} )
B. ( 0.4 mathrm{ms}^{-1} )
( mathrm{c} cdot 4 mathrm{cms}^{-1} )
D. ( 0.4 mathrm{mms}^{-1} )
12
1388Assertion
Electromotive force is a force which
help the electrons to flow and produce
current.
Reason
Electromotive force is independent of
the voltage across the cell
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
1389Explain with the help of a labelled diagram the distribution of a magnetic field due to a current through a circular loop. Why is it that if a current carrying loop has n turns the field produced
at any point is ( n ) times as large as that produced by a single turn?
12
1390The electric current in a circuit is given by ( i=frac{i_{0} t}{tau} ) for some time. The rms
current for the period ( t=0 ) to ( t=tau ) will
be
( mathbf{A} cdot i_{0} sqrt{frac{T}{3}} )
B. ( frac{i_{0}}{sqrt{3}} )
( c cdot frac{i_{0}}{2} )
D. ( frac{i_{0}}{3} )
12
1391In making an Ohm’s law circuit, which of the following connection is correct?
A. Voltmeter is series and ammeter in parallel
B. Voltmeter in parallel and ammeter in series
c. voltmeter and ammeter both are in parallel
D. Voltmeter and ammeter both are in series
12
1392A potentiometer wire of length ( 1 mathrm{m} ) has a resistnce of ( 10 Omega ).It is connected to a 6 v
battery in series with a resistance of ( 5 Omega ) Determine the emf of the primary cell which gives a balance point at ( 40 mathrm{cm} )
12
1393The power supplied by the battery will be:
A. ( 15 mathrm{w} )
B. 24 W
c. ( 3.6 mathrm{w} )
D. 20 W
12
1394Find the equivalent resistance across
( A B ) for the given circuit:
A . ( 1 Omega )
B. ( 2 Omega )
( c .3 Omega )
D. ( 4 Omega )
12
1395The unit of resistivity of the material is
A . ( Omega )
в. ( Omega m )
( c . Omega / m )
D. ( m / Omega )
12
139610. If resistance S in RB = 30092, then the balanced length is
found to be 25.0 cm from end A. The diameter of unknown
wire is 1mm and length of the unknown wire is 31.4 cm.
The specific resistivity of the wire should be
(a) 2.5 x 10-2-m (b) 3.5 x 1042-m
(c) 4.5 x 10-2-m (d) None of these
12
1397State the working principle of a potentiometer with the help of the circuit diagram, explain how a potentiometer is used to compare the emf’s of the two primary cell obtain the required expression used for comparing
the emf’s.
12
1398The resistivity of a wire varies with its
A . length
B. cross-section
c. mass
D. material
12
resistance of ( 12 Omega ) are connected thick
conducting strips, as shown in the figure. A battery and a galvanometer (With a sliding jockey connected to it) are also available connections are to be made to
measure the unknown resistance ( boldsymbol{X} )
using the principle of Wheatstone bridge. Answer the following questions.
(a) Are there positive and negative terminals on the galvanometer
(b) copy the figure is your answer book and show the battery and the galvanometer (With jockey) connected at appropriate points.
(c) After appropriate connections are made, it is found that no deflection
takes place in the galvanometer when the sliding jockey touches the wire at a
distance of ( 60 mathrm{cm} ) from ( A . ) Obtain the
value of the resistance of ( boldsymbol{X} )
12
1400Which of the following is used for the formation of thermistor?
A. copper oxide
B. Nickel oxide
c. Iron oxide
D. All of the above
12
1401What is the p.d. across the terminals
( left(V_{T}right) ) of a cell with emf ( E ) for open circuit
( ? )
A ( cdot V_{T}E )
c. ( V_{T}=0 )
D. ( V_{T}=E )
12
1402A motor rated ( 500 mathrm{W}, 230 mathrm{V} ) utilizes 3
units of electrical energy. Calculate the time for which the motor works.
12
1403toppr
circuited and the current i is measured.
Which of the following graphs give
correct relationship between i and n?
( A )
( B )
( c )
( D )
12
1404A cylindrical conductor is placed near other positively charged conductor. The net charge acquired by the cylindrical conductor will be :
A. Positive only
B. Negative only
c. zero
D. Either positive or negative
12
1405A resistor connected to a battery is heated due to current through it. Which of the following quantity does not vary?
A . resistance
B. drift velocity
c. resistivity
D. number of free electrons
12
1406The areas of cross section of two wires
of the same material are in the ratio 1:
2 and their lengths are in the ratio 2: 1
If their ends have the same potential differences then currents through
them will be in the ratio of
A .1: 2
B . 2: 1
c. 1: 4
D. 4: 1
12
1407If the current in the primary circuit is decreased,then balancing length is obtained in the potentiometer is at:
A. Lower length
B. Higher length
c. Same length
D. 1/3rd length
12
1408In a meter bridge, the wire of length ( 1 mathrm{m} )
has a non-uniform cross-section such
that, the variation ( frac{d R}{d l} ) of its resistance ( R ) with length ( l ) is ( frac{d R}{d l} propto frac{1}{sqrt{l}} . ) Two equal
resistances are connected as shown in
the figure. The galvanometer has zero deflection when the jockey is at point ( P ) What is the length ( A P: )
( A cdot 0.2 m )
В. ( 0.3 m )
c. ( 0.25 m )
D. ( 0.35 m )
12
1409The length and area of cross-section of a conductor are doubled, its resistance
is
A. unchanged
B. halvedd
c. doubled
12
1410A current of ( 5 mathrm{A} ) is passing through a
metallic wire of length ( 5 mathrm{m} ) and crosssectional area of ( 10^{-5} m^{2} . ) If the density
of the electrons in the wire is ( 6.25 x )
( 10^{26} m^{3}, ) find the time taken by the
electrons to travel from one end of the
wire to the other.
12
1411Two dimetrically opposite points of a metal ring are connected to two terminals of the left gap of metrebridge.
The resistance of ( 11 Omega ) is connected in
right gap. If null point is obtained at a distance of ( 45 mathrm{cm} ) from the left end, find
the resistance of metal ring.
12
1412In a potentiometer using two cells in series gives a balance length of ( 600 mathrm{cm} ) When the same cells are connected
opposing each other then balance length is ( 100 mathrm{cm} ). The ratio of
emf of larger to smaller cell is:
A .7: 5
в. 5: 7
( c cdot 6: 1 )
D. 1: 6
12
1413In the given (a) calculate the effective
resistance of the circuit and (b)
calculate the reading of the ammeters
( A_{1} A_{2} ) and ( A_{1} ) If ( R_{1}=10 Omega ) and ( R_{2}=6 Omega )
and ( boldsymbol{E}=mathbf{1 0} boldsymbol{V} )
12
1414A battery of emf ( E_{0}=12 mathrm{V} ) is connected across a ( 4 mathrm{m} ) long uniform wire having
resistance ( frac{4 Omega}{m} . ) The cells of small emfs ( varepsilon_{1} )
( =2 V ) and ( varepsilon_{2}=4 V ) having internal
resistance ( 2 Omega ) and ( 6 Omega ) respectively, are connected as shown in the figure. If
galvanometer shows no deflection at the point ( mathrm{N} ), find the distance of point ( mathrm{N} )
from the point ( mathbf{A} )
12
1415A wire of uniform cross-section has a
resistance of ( boldsymbol{R} ) Omega. What would be the
resistance of a similar wire, made of the
same material, but twice as long and of
twice the diameter?
A ( cdot frac{3}{2} R )
в. ( frac{5}{2} R )
c. ( frac{1}{2} R )
D. ( frac{1}{4} R )
12
1416What is the resistance, under normal working conditions, of an electric lamp rated ‘240 ( V, 60 mathrm{W} ) ? If two such lamps are connected in series across a ( 240 mathrm{V} )
mains supply, explain why each one appears less bright.
12
1417( frac{2}{2} )12
1418A given resistor has the following colour code of the various strips on it : Brown,
black, green and silver. The value of its
resistance in ohm is
A ( cdot 1.0 times 10^{4} pm 10 % )
B . ( 1.0 times 10^{7} pm 5 % )
C. ( 1.0 times 10^{6} pm 10 % )
D. ( 1.0 times 10^{5} pm 5 % )
E . ( 1.0 times 10^{3} pm 10 % )
12
1419Name the instrument used to control
the current in an electric circuit.
A. Rheostat
B. Voltmeter
c. Ammeter
D. Galvanometer
12
1420Resistance of a resistor at temperature
( t^{circ} boldsymbol{C} ) is ( boldsymbol{R}_{t}=boldsymbol{R}_{0}left(mathbf{1}+boldsymbol{alpha} boldsymbol{t}+boldsymbol{beta} boldsymbol{t}^{2}right), ) where ( boldsymbol{R}_{0} )
is the resistance at ( 0^{circ} mathrm{C} ). The
temperature coefficient of resistance at
temperature ( t^{circ} C ) is
A ( cdot frac{left(1+alpha t+beta t^{2}right)}{alpha+2 beta t} )
B. ( (alpha+2 beta t) )
c. ( frac{alpha+2 beta t}{left(1+alpha t+beta t^{2}right)} )
D. ( frac{alpha+2 beta t}{2left(1+alpha t+beta t^{2}right)} )
12
1421All free charges are integral multiple of
a basic unit charge ( e . ) Then quantization rule of electric charge implies
( mathbf{A} cdot Q=e )
в. ( Q=frac{1}{e} )
c. ( Q=n e )
D. ( Q=e^{2} )
12
1422When current flows through a
conductor, then the order of drift
velocity of electrons will be:-
( mathbf{A} cdot 10^{10} mathrm{cms}^{-1} )
B. ( 10^{-2} mathrm{cms}^{-1} )
( mathbf{c} cdot 10^{4} c m s^{-1} )
D. ( 10^{-1} mathrm{cms}^{-1} )
12
1423Derive the balancing condition of a
Wheatstone bridge.
12
1424How much greater is one micro coulomb compared to an electronic
charge?
A ( cdot 10^{13} ) times
B. ( 10^{10} ) times
( mathbf{c} cdot 10^{11} ) times
D. ( 10^{6} ) times
12
1425Kirchoffs 1st and 2nd laws are based on
conservation of
A. Energy and charge respectively
B. Charge and energy respectively
c. Mass and charge respectively
D. None of these above
12
1426Color of the four strips of carbon
resistor are respectively orange, green golden, silver. Then its resistance is :
( mathbf{A} cdot 2.5 pm 10 % ) ohm
B. ( 3.5 pm 5 % ) ohm
c. ( 3.5 pm 10 % ) ohm
( mathbf{D} cdot 350 pm 10 % ) ohm
12
1427Constantan wire is used for making
standard resistance, because it has
A. high melting point.
B. low specific resistance
C . high specific resistance.
D. negligible temperature coefficient of resistance.
12
1428Three resistances are joined together to
form a letter ( Y ) as shown in the figure.If
the potentials of the terminals ( mathbf{A}, mathbf{B} ) and
( mathrm{C} ) are ( mathrm{V}_{1}, mathrm{V}_{2} ) and ( mathrm{V}_{3} ) respectively, then
determine the potential of the node ( boldsymbol{O} )
( ^{mathbf{A}} cdotleft[frac{V_{1}}{R_{1}^{frac{1}{1}}}+frac{V_{2}}{R_{2}^{2}}+frac{V_{3}}{R_{3}^{3}}right]left[frac{1}{R_{1}}+frac{1}{R_{2}}+frac{1}{R_{3}}right]^{-2} )
( ^{mathbf{B}} cdotleft[frac{V_{1}}{R_{1}}+frac{V_{2}}{R_{2}}+frac{V_{3}}{R_{3}}right]left[frac{1}{R_{1}}+frac{1}{R_{2}}+frac{1}{R_{3}}right]^{-1} )
( mathbf{C} cdotleft[frac{V_{1}}{R_{1}}+frac{V_{2}}{R_{2}}+frac{V_{3}}{R_{3}}right]left[R_{1}+R_{2}+R_{3}right] )
D. ( left[frac{V_{1}}{R_{2}^{2}}+frac{V_{2}}{R_{2}^{2}}+frac{V_{3}}{R_{2}}right]left[R_{1}^{2}+R_{2}^{2}+R_{3}^{2}right] )
12
1429If resistance of wire at ( 50^{circ} mathrm{C} ) is ( 5 mathrm{R} Omega ) and
( 100^{circ} mathrm{C} ) is ( 6 mathrm{R} Omega, ) find resistance of ( 0^{circ} mathrm{C} )
12
1430N lamps each of resistance ( r, ) are fed by a machine of resistance R. If light
emitted by any lamp is proportional to
the square of the heat produced, prove that the most efficient way of arranging
them is to place them in parallel arcs,
each containing n lamps, where n is the
integer nearest to.
( ^{mathbf{A}} cdotleft(frac{r}{N R}right)^{3 / 2} )
( ^{mathbf{B}} cdotleft(frac{N R}{r}right)^{1 / 2} )
( mathbf{C} cdot(N R r)^{3 / 2} )
D. ( (N R r)^{1 / 2} )
12
1431A house is fitted with ten lamps of each
( 60 W . ) Each lamp burns for 5 hrs a day
on an average. The cost of consumption in a month of 30 days at 2.80 rupees
per unit is:
A . Rs.152
B. Rs.252
c. ( R s .352 )
D. Rs.452
12
1432In an experiment, the resistance of a
material is plotted as a function of temperature (in some range). As shown in the figure, it is a straight line. One may conclude that:
A ( cdot R(T)=frac{T_{0}}{T^{2}} )
B . ( R(T)=R_{0} e^{-T^{2} / T_{0}^{2}} )
C ( cdot R(T)=R_{0} e^{-T_{0}^{2} / T^{2}} )
D. ( R(T)=R_{0} e^{T^{2} / T_{0}^{2}} )
12
1433In a potentiometer experiment, the balancing length of potentiometer of a cell of e.m.f ( 1.5 mathrm{V} ) in the secondary is 440 cm. A resistance ( 5 Omega ) is connected
between the terminals of cell, the balancing length is ( 400 mathrm{cm} . ) Then
a) internal resistance of the cell is ( 0.5 Omega )
b) terminal voltage of the cell is ( 15 / 11 v )
c) Potential gradient of the potentiometer wire is ( frac{1.5}{40} V / c m )
d) potential difference across the potoentiometer wire of length ( 10 mathrm{m} ) is nearly ( 3.4 mathrm{V} )
A. a,b are correct
B. a,b and c are correct
( c . ) a, b and d are correct
D. a,b,c and d are correct
12
1434A current of ( 5 A ) passes through a copper conductor (resistivity ( =1.7 times )
( 10^{-8} Omega m ) ) of radius of cross-section
5 ( m ) m. Find the mobility of the charges if
their drift velocity is ( 1.1 times 10^{-3} m / s )
A ( cdot 1.3 m^{2} / V s )
B. ( 1.5 mathrm{m}^{2} / mathrm{Vs} )
( mathbf{c} cdot 1.8 m^{2} / V s )
D. ( 1.0 m^{2} / V s )
12
1435The potentiometer wire AB is made of
two equal parts ( A N ) and ( N B ) of cross
sectional radius ( 2 r ) and ( r )
respectively.The material of both parts is same. A cell is connected between ( mathbf{A} )
and B. The potential gradient in the part
AN is ( 1 V / m . ) Potential difference
between two points ( C ) and ( D ) (shown in figure) separated by ( 20 mathrm{cm} ) is found to
be ( 0.5 V . ) The separation between ( C ) and ( mathrm{N} ) is ( frac{t}{3} mathrm{cm} . ) Then ( t ) is
12
1436The number of free electrons per ( 10 mathrm{mm} )
ordinary copper wire is about ( 2 times 10^{21} )
The average drift speed of the electrons is ( 0.25 mathrm{mm} ) current flowing is:
A. ( 0.8 mathrm{A} )
B. 8 A
( c .80 mathrm{A} )
D. 5 A
12
1437For the following circuits, the potential
difference between ( X ) and ( Y ) in volt is:
4
B. 4 3
( c )
D. 5
12
1438A piece of wire of resistance ( 4 Omega ) is bent
through ( 180^{circ} ) at its mid point and the
two halves are twisted together, then
resistance is :
A . ( 1 Omega )
B. 2Omega
c. ( 5 Omega )
D. 8Omega
12
1439Refer to teh circuit shown. What will be
the total power dissipation in the
circuit if ( boldsymbol{P} ) is the power dissipated in
( R_{1} ? ) It is given that ( R_{2}=4 R_{1} ) and ( R_{3}= )
( 12 R_{1} )
A ( .4 P )
в. ( 7 P )
c. ( 13 P )
D. ( 17 P )
12
1440A ( 10 V ) olts battery of internal resistance
one ohm is connected to a ( 20 mathrm{V} ) olt
battery of internal resistance 2ohm. The
combination is put across a resistance
of 30 oh ( m . ) Find the current through
each battery
12
1441State whether given statement is True or False.

Silver is a good conductor of electricity.
A. True
B. False

12
1442( mathbf{A} )
( 1 k W ) heater is meant to operate at
( 200 V . ) How many units of electrical
energy will it consume in a month (of 30
days) if it operates 10 h daily at the specified voltage ( (200 vee) ? )
12
1443Calculate the power of an electric bulb which consumes 2400 Jin a minute
( A cdot 80 w )
B. 120 W
( c cdot 60 w )
D. ( 40 mathrm{w} )
12
1444Five identical resistor are initially arranged a shown in the figure be clear
lines. If two similar resistances
are added as shown by the dashed lines
then change in resistance in final and
initial arrangement is
( mathbf{A} cdot 2 Omega )
B. ( 1 Omega )
( c cdot 3 Omega )
D. ( 4 Omega )
12
1445A cylindrical rod is reformed to half of its original length keeping volume constant. If its resistance before this
change were ( R ), then the resistance after
reformation of rod will be.
( A cdot R )
в. ( R / 4 )
c. ( 3 R / 4 )
D. ( R / 2 )
12
1446Human nails are good insulators
A . True
B. False
12
1447In the following figure the current
through ( 4 Omega ) resistor is
( 4 cdot 1.4 mathrm{A} )
B. ( 0.4 mathrm{A} )
( c cdot 1.0 A )
D. 0.7
12
1448What is the current drawn from the
source in the given circuit?
( A cdot 2 A )
B. 1.5
( c cdot 4 A )
D. 3 A
12
1449A transformer with turns ratio ( frac{N_{1}}{N_{2}}= ) ( mathbf{5 0} )
( frac{w}{1} ) is connected to a 120 volt ( A C ) supply
If primary and secondary circuit resistance are ( 1.5 k Omega ) and ( 1 Omega )
respectively then find out power out put
A ( .5 .76 mathrm{w} )
B. ( 11.4 mathrm{w} )
c. ( 2.89 mathrm{w} )
D. ( 7.56 mathrm{w} )
12
1450The electron beam in a television
picture tube travels a distance lin evacuated space of the tube. If the speed of the electrons is ( v ) and the beam
current is i, then the number of
electrons in the beam at any instant will
be
A. ( frac{i l}{e v} )
в. ( frac{i}{l e v} )
c. ( frac{v}{i l e} )
D. ( frac{e}{i l v} )
12
1451Two cells of the same emf ( e ) but
difference internal resistances ( r_{1} ) and
( r_{2} ) are connected in series with an
external resistance ( R ). The potential
drop across the first cell is found to be
zero. The external resistance ( boldsymbol{R} ) is
A ( cdot r_{1}-r_{2} )
в. ( r_{1} / r_{2} )
( c cdot r_{1} r_{2} )
D. ( r_{1}+r_{2} )
12
1452A 10 m long potentiometer wire is
connected to a battery having a steady voltage. A Leclanche cell is balanced at
( 4 m ) length of the wire. If the length is kept the same, but its cross-section is doubled, the null point will be obtained
at:
( mathbf{A} cdot 8 m )
в. ( 4 m )
c. ( 2 m )
D. None of these
12
1453For a cell the graph between the potential difference (V) across the
terminals of the cells and the current (I)
drawn from the cell is shown in the
figure. The emf and the internal
resistance of the cell are:
12
1454In a potentiometer of 10 wires, the
balance point is obtained on the ( 7^{t h} )
wire. To shift the balance point to ( 9^{t h} ) wire, we should.
A. Decrease resistance in the main circuit
B. Increase resistance in the main circuit
c. Decrease resistance in series with the cell whose emf is to be measured
D. Increase resistance in series with the cell whose emf is to be determined
12
1455A circular conductor is made of a
uniform wire of resistance ( 2 times )
( 10^{-3} ) ohm / meter and the diameter of
this circular conductor is 2 meter. Then
the resistance measured between the
ends of the diameter is (in ohms):
A ( cdot pi times 10^{-3} )
В. ( 2 pi times 10^{-3} )
c. ( 4 pi times 10^{-3} )
D. ( 4 times 10^{-3} )
12
1456Find emf of the cell ( E_{2} )
A. ( 2 v )
B. 1.5
( c cdot 1 v )
D. 1.75 V
12
1457Potentiometer wire Pq of length Im is
connected to a standard cell ( boldsymbol{E}_{1} ) Another
cell of E2 of emf1.02v/s connected as
shown in the circuit diagram with a
resistance ‘r’ and with a switch ‘s’. With
the switch ( mathrm{S} ) open, null position is
obtained at a distance of ( 51 mathrm{cm} ) from
p,Calculate
A. Potential gradient of the wire.
B. emf of the cell
C. When switch S is closed, will null point moves towards p or ( Q ? )
D. insufficient data
12
1458For determination of resistance of a coil
which of two methods is better Ohm’s
Law method or metre bridge method?
12
1459Three equal resistors, connected across a source of e.m.f. together dissipate 10 watt of power. What will be the power
dissipated in watts if the same resistors are connected in parallel across the same source of e.m.f.
A . ( 10 V )
в. ( 10 / 3 V )
c. ( 30 V )
D. ( 90 V )
12
1460An electric heater operating at ( 220 mathrm{V} ) boils ( 5 l ) of water in 5 minutes. If it is
used on a ( 110 mathrm{V} ) line, it will boil the
same amount of water in:
A . 10 minutes
B. 20 minutes
c. 5 minutes
D. 1 minute
12