1

Work sheet jee model. Chapter 3

JEE MAIN - PHYSICS

Section A [4]

1) In the following circuit, the reading of the voltmeter V a) All of these

is: b) Drift velocity of electron increases
c) Electron current decreases.
d) Electric field decreases.

[4] 6) Two batteries of emf 4 V and 8V with internal resistance

a) 8 V b) 12 V 1 ohm and 2 ohm are connected in a circuit with a
c) 16 V d) 20 V resistance of 9 as shown in the figure. The current and
potential difference between the points P and Q are:
2) A galvanometer has a resistance of 3663 ohm. A shunt S
is connected across it such that ( 34
1
) of the total current
passes through the galvanometer. Then, the multiplying
power of the shunt is: [4]
a) 35 b) 34
[4]
c) 33 d) 1
a) 1
A and 9V
3) A potential difference is applied across the ends of a 9
b) 1
A and 4V
metallic wire. If the potential difference is doubled, the 6
c) 1
A and 3V
drift velocity: [4] 3
d) 1
A and 12V
a) Will be doubled
12
7) In the adjoining circuit diagram, the current through the
b) Will remain unchanged
battery and the charge on the capacitor respectively in
c) Will be quadrupled
steady - state are:
d) Will be halved
4) In the given circuit diagram when the current reaches
steady state in the circuit, the charge on the capacitor of
capacitance C will be:

[4]
a) 1 A and 3µ C
b) 17 A and 0µ C
c) 11 A and 3µ C
d) 67 A and 12
7 µ C
[4]
8) A uniform copper wire of length 1 m and cross - sectional
a) CE area 5× 10 - 7 m2 carries a current of 1 A. Assuming
b) CE (r1r+r)
1
that there are 8 × 1028 free electron/m3 in copper, how
c) r1
CE (r2 +r) long will an electron take to drift from one end of the
d) r2
CE (r+r wire to the other? [4]
2)
a) 0.8× 103 s b) 1.6× 103 s
5) In the given figure, a battery of emf E is connected across c) 3.2× 10 s 3
d) 6.4× 103 s
a conductor PQ of lengthland different area of cross -
sections having radii r1 and r2 (r2 < r1 ). Choose the correct 9) In an electrolyte 3.2× 1018 bivalent positive ions drift
option as one moves from P to Q: to the right per second while 3.6 × 1018 monovalent
negative ions drift to the left per second. Then, the
current is: [4]
a) 0.45 amp to the right
b) 1.6 amp to the right
c) 0.45 amp to the left
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d) 1.6 amp to the left E2 . The internal resistances of the two batteries are r1
and r2 respectively:
10) In the following circuit diagram the potential difference
across the plates of the capacitor C is:

[4]
a) E2 r2 < E1 (R + r2 ) b) E2 r1 > E1 (R + r2 )
[4] c) E1 r1 > E2 (R + r1 ) d) E1 r2 > E2 (R + r1 )
a) 1.0 volt b) 1.5 volt
c) Zero d) 2.5 volt 18) Thermal speed of free electrons is of the order of: [4]
a) 105 m/sec b) 100 m/sec
11) A wire of resistance R1 is drawn out so that its length c) 10 - 2
cm/sec d) Zero
is increased by twice of its original length. The ratio of
19) A resistance R is to be measured using a meter bridge.
new resistance to original resistance is: [4]
a) 1 : 9 b) 4 : 1 The student chooses the standard resistance S to be 100
c) 9 : 1 d) 3 : 1 Q. He finds the null point at l1 = 2.9 cm. He is told to
attempt to improve the accuracy. Which of the following
12) A potential difference V is applied to a conductor of is a useful way? [4]
length l and radius r. When l is doubled without chang-
ing the potential difference, then the drift velocity is: a) He should change S to 1000Ω and repeat the exper-
[4] iment.
a) Quadrupled b) Halved b) He should give up hope of a more accurate mea-
c) Unchanged d) Doubled surement with a meter bridge.
c) He should change S to 3Ω and repeat the experiment.
13) During an experiment with a meter bridge, the galvanome- d) He should measure l1 more accurately.
ter shows a null point when the jockey is pressed at 40.0
cm using a standard resistance of 90Ω , as shown in the 20) Which of the following will NOT be observed when
scale used in the meter bridge is 1 mm. The unknown a multimeter (operating in resistance measuring mode)
resistance is probes connected across a component, are just reversed?
i. Multimeter shows an equal deflection in both cases
i.e. before and after reversing the probes if the
chosen component is resistor.
ii. Multimeter show’s NO deflection in both cases i.e.
before and after reversing the probes if the chosen
[4] component is capacitor.
a) 135 ± 0.56Ω b) 135 ± 0.23Ω iii. Multimeter shows a deflection, accompanied by a
c) 60 ± 0.15Ω d) 60 ± 0.25Ω splash of light out of connected and NO deflection
14) To get maximum current in resistance of 3 ohms, one on reversing the probes if the chosen component is
can use n rows of m cells (connected in series) connected LED.
in parallel. If the total number of cells is 24 and the iv. Multimeter shows NO deflection in both cases i.e.
internal resistance of a cell is 0.5 ohms then: [4] before and after reversing the probes if the chosen
a) M = 2, n = 12 b) M = 12, n = 2 component is metal wire.
c) M = 8, n = 3 d) M = 6, n = 4 [4]
a) Option (iii) b) Option (ii)
15) What are the potentials at P and Q in the circuit shown c) Option (i) d) Option (iv)
here?
21) A constant voltage is applied between the two ends of
a uniform metallic wire. Some heat is developed in it.
The heat developed is doubled if: [4]

a) Both the length and the radius of the wire are

doubled
[4]
b) Both the length and the radius of the wire are halved
a) 15 volt and +10 volt c) The length of the wire is doubled
b) +10 volt and +5 volt d) The radius of the wire is doubled
c) - 15 volt and - 10 volt
d) - 10 volt and - 5 volt 22) In a closed circuit, the vector sum of total emf is equal
to the sum of the . [4]
16) Drift speed of electrons, when 1.5 A of current flows in
a copper wire of cross - section 5 mm2 is v. If the a) Products of currents and the resistances
electron density in copper is 9 × 1028 /m3 , the value of b) Resistances
v in mm/ s is close to (Take, the charge of an electron c) Products of potential differences
to be = 1.6 × 10 - 19 C) [4] d) Currents
a) 0.02 b) 3
23) Figure below shows a balanced Wheatstone net. Now,
c) 2 d) 0.2
it is disturbed by changing P to 11 ohms. Which of
17) Under what conditions current passing through a resistance the following steps will not bring the bridge to balance
can be increased by short - circuiting the battery of emf again?
 3

[4]

a) Increasing R by 2 ohm [4]

b) Making product RQ = 2200 (ohm)2 a) 9 b) 21.2
c) Increasing S by 20 ohm c) 14.5 d) 11.6
d) Increasing Q by 10 ohm
31) The current in a circuit containing a battery connected to
2Ω resistance is 0.9 A. When a resistance of 7 Ω is
24) A wire of resistance R is cut into n equal parts. These connected to the same battery, the current observed in
parts are then connected in parallel. The equivalent re- the circuit is 0.3 A. Then the internal resistance of the
sistance of the combination will be: [4] battery is: [4]
a) N/R b) R/n2 a) 1Ω b) 0.5Ω
c) R/n d) NR c) 0.1Ω d) 0
32) An electric cable of copper has just one wire of radius
9 mm. Its resistance is 14Ω . If this single copper wire
of the cable is replaced by seven identical well insulated
copper wires each of radius 3 mm connected in parallel,
then the new resistance of the combination will be: [4]
a) 18Ω b) 9Ω
25) c) 126Ω d) 28Ω
In the circuit shown, the resistance r is a variable resis- 33) In the circuit shown below, the current in the IΩ resistor
tance. If for r = fR, the heat generation in r is maximum is
then the value of f is: [4]
a) 34 b) 14
c) 21
d) 1
26) The lamp of a flash light is of 1.5 Q resistance. It uses
3 cells each of 1.5 V and internal resistance 0.25 Q.
What is the net potential difference across the lamp? [4] [4]
a) 1.5 V b) 4.5 V a) 0.13 A, from Q to P b) 1.3 A, from P to Q
c) 3V d) 2.25 V c) 0 A d) 0.13 A, from P to Q
27) Two square metal plates A and B are of the same thick- 34) Thirteen resistances each of resistance R ohm are con-
ness and material. The side of B is twice that of A. nected in the circuit as shown in the adjoining figure.
These are connected as shown in series. If the resistances The effective resistance between A and B is:
of A and B are denoted by RA and RB , then (RA /RB ) is:

[4] [4]
a) 1/2 b) 1/1 a) 4R b) 2R
3 Ω 3 Ω
c) 2/1 d) 4/1 c) 2RΩ d) 2Ω
28) Two unknown resistances X and Y are connected to left 35) A potential difference of 10 V is applied across a conduc-
and right gaps of a metre bridge and the balancing point tor of length 0.1 m. If the drift velocity of electrons is 2×
is obtained at 80 cm from left. When a 10Ω resistance 10 - 4 m/s, the electron mobility is m2 V - 1 s - 1 .
is connected in parallel to X the balancing point is 50 [4]
cm from left. The values of X and Y respectively are: a) 3× 10 - 6
b) 1× 10 - 6

[4] c) 4× 10 - 6
d) 2× 10 - 6

36) The maximum current that flows in the fuse wire, before
a) 40Ω , 9 Ω
it blows out, varies with the radius r as: [4]
b) 10Ω , 3 Ω a) R b) R1/2
c) 30Ω , 7.5 Ω c) R 2/3
d) R3/2
d) 20Ω , 6 Ω
37) A 10 V battery with internal resistance of 1 ohm and
29) A wire of resistance R is stretched till its length is double a 15 V battery with internal resistance of 0.6 ohm are
of the original wire. Then, the resistance of the stretched connected in parallel to a voltmeter (see figure). The
wire is: [4] reading in the voltmeter will be close to:
a) 2R b) 8R
c) 16R d) 4R
30) In the given circuit the equivalent resistance between the
points A and B is (in ohm):
 4

44) If the ammeter A shows a zero reading in the circuit

shown below, the value of resistance R is:

[4]
a) 24.5 V b) 12.5 V
c) 11.9 V d) 13.1 V [4]
38) In the circuit shown in figure below, the voltage drop a) 500Ω b) 41.5Ω
across the 15 ohm resistor is 30 volts having the polarity c) 125Ω d) 100Ω
as indicated. Then the value of R must be: 45) Ohm’s law is valid for: [4]
a) Diode when current flows
b) Metallic conductors at low temperature
c) Metallic conductors at high temperature
[4] d) Electrolytes when current passes through them
a) 35 ohm b) 37.5 ohm
46) For ensuring dissipation of same energy in all three re-
c) 10 ohm d) 17.5 ohm
sistors (R1 , R2 , R3 ) connected as shown in figure, their
39) Five identical lamps, each of resistance 1100 ohm are values must be related as
connected to 220 volt as shown in the following figure.
The reading of an ideal ammeter A is:

[4]

[4] a) R2 = R3 and R1 = R42

b) R1 = R2 + R3
a) 220
1100 × 5 amp c) R2 = R3 and R1 = 4R2
b) 220
1100 × 3amp d) R1 = R2 = R3
c) 220
× 2 amp
47) A current of 6 A enters one corner P of an equilateral
1100
d) 220
× 1amp
triangle PQR having 3 wires of resistances 2Ω each and
1100
40) A beam of electrons moving at a speed of 106 m/s along leaves by the corner R. Then, the current I1 and I2 are:
a line produces a current of 1.6 × 10 - 6 A. The number
of electrons in the 1 metre of the beam is: [4]
a) 107 b) 1019
c) 10 6
d) 1013
41) The value of current I in the following circuit is:

[4]
a) 4A, 2A b) 2A, 4A
c) 1A, 2A d) 2A, 3A
[4]
a) 13A b) 3A 48) A steady current is passing through a linear conductor
c) - 3A d) 23A of non - uniform cross - section. The net quantity of
charge crossing any cross - section per second is: [4]
42) In the following figure, the value of resistor to be con-
nected between C and D so that the resistance of the a) Directly proportional to the area of cross - section
entire circuit between A and B does not change with the b) Inversely proportional to the length of conductor
number of elementary sets used is: c) Directly proportional to the length of conductor
d) Independent of area of cross - section
49) The equivalent resistance of the circuit shown below be-

tween points a and b is:

[4] √ [4]
a) R(√3 + 1) b) 3R a) 3.2Ω b) 16Ω
c) R( 3 − 1) d) R c) 20Ω d) 24Ω
43) An electron is moving in a circular path of radius 0.5 m 50) In the following figure the equivalent resistance between
with a period of 10 - 19 s. The current constituted in the A and B is:
circular path is: [4]
a) 0.1 A b) 1.6 A
c) 2.5 A d) 1.9 A
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[4] a) 24Ω b) 6Ω
a) 8Ω b) 2.5Ω c) 8Ω d) 16Ω
c) 5Ω d) 6.8Ω
57) All the bulbs below are identical. Which bulb(s) light(s)
51) The number of dry cells, each of emf 1.5 volt and in- most brightly?
ternal resistance 0.5Ω that must be joined in series with
a resistance of 20 ohm so as to send a current of 0.6
ampere through the circuit is: [4]
a) 10 b) 2
c) 12 d) 8
[4]
52) Two rods are joined end to end, as shown. Both have a) 3 and 4 b) 2 only
a cross - sectional area of 0.01 cm2 . Each is 1 meter c) 1 only d) 1 and 5
long. One rod is of copper with a resistivity of 1.7 ×
10 - 6 ohm - cm, the other is of iron with a resistivity 58) Calculate current i in the adjoining circuit.
of 10 - 5 ohm - cm. How much voltage is required to
produce a current of 1 ampere in the rods?

[4]
[4] a) 0.3 amp b) 0.4 amp
a) 0.00145 V b) 0.0145 V c) 0.1 amp d) 0.2 amp
c) 0.117 V d) 1.7× 10 - 6
V
59) Five cells each of emf E and internal resistance r send
53) Two similar accumulators each of emf E and internal re- the same amount of current through an external resistance
sistance r are connected as shown in the adjoining figure. R whether the (cells
) are connected in parallel or in series.
Then, the potential difference between the points X and Then the ratio Rr is: [4]
Y is: a) 2 b) 15
c) 21
d) 1
60) A galvanometer having a coil resistance of 100Ω gives
a full - scale deflection when a current of 1 mA is
[4] passed through it. The value of the resistance which can
a) E b) 2E convert this galvanometer into ammeter giving a full -
c) 4E d) Zero scale deflection for a current of 10 A, is [4]
54) An ammeter and voltmeter are joined in series to a cell. a) 0.01Ω b) 0.1Ω
The readings are x and y respectively. If resistance is c) 3Ω d) 2Ω
joined in parallel with a voltmeter: [4] 61) The voltage of clouds is 4× 106 volt with respect to
ground. In a lightning strike lasting 1000 ms, a charge
a) X will decrease and y will increase of 4 coulomb is delivered to the ground. The power of
b) Both x and y will increase the lightning strike is [4]
c) Both x and y will decrease a) 20 MW b) 16 MW
d) X will increase and y will decrease c) 80 MW d) 500 MW
55) In a Wheatstone bridge (see figure), resistances P and Q 62) In the adjoining circuit, if a conducting wire is connected
are approximately equal. When R = 400Ω , the bridge between points A and B, the current in this wire will:
is balanced. On interchanging P and Q , the value of R
for balance is 405 Ω . The value of X is close to

[4]
[4] a) Flow from B to A
a) 403.5Ω b) 402.5Ω b) Flow from A to B
c) 404.5Ω d) 401.5Ω c) Flow in the direction which will be decided by the
56) The equivalent resistance of the network shown in the value of V
figure between points A and B is: d) Be zero
63) The equivalent resistance between points A and B in the
following figure is:

[4]
 6

[4]
a) 40Ω b) 5Ω
c) 20Ω d) 10Ω
64) A battery of internal resistance 4Ω is connected to the
network of resistances as shown in figure. In order that
the maximum power can be delivered to the network, the
value of R in Ω should be
[4]
a) 3R√ b) R √
c) R( 3 − 1) d) R( 3 + 1)
71) In the electric network shown, when no current flows
through the 4Ω resistor in the arm EB, the potential
difference between the points A and D will be:
[4]
a) 18 b) 2
c) 4/9 d) 8/9
65) When the key K is pressed at time t = 0, then which of
the following statements about the current I in the resistor
AB of the given circuit is true?

[4]

a) At t = 0, I = 2 mA and with time it goes to 1 mA [4]

b) I oscillates between 1 mA and 2 mA a) 5 V b) 4 V
c) I = 2 mA at all times c) 3 V d) 6 V
d) I = 1 mA at all times 72) Current - voltage characteristics of two elements A and
B are shown in figures (1) and (2) respectively:

66) The H amount of thermal energy is developed by a resis-

tor in 10 s when a current of 4 A is passed through it.
Which of the following graphs represents current - voltage
If the current is increased to 16 A, the thermal energy
characteristics for their series combination? [4]
developed by the resistor in 10 s will be: [4]
a) H4 b) 4H
c) 16 H d) H
67) N cells of emfs E1 , E2 , E3 , En and internal resistance
r1 , r2 , r3 , ..., rn are connected in series to form a closed a)
circuit with zero external resistance. For each cell the
ratio of emf to internal resistance is K, where K is a
constant; the terminal potential of each cell is: [4]
a) K b) Zero
b)
c) K2 d) ∞
68) For a cell the terminal potential difference is 2.2 V when
the circuit is open and reduces to 1.8 V when the cell is
connected to a resistance R = 5Ω . The internal resistance c)
of the cell (r) is: [4]
a) 109 Ω b) 10 9
Ω
c) 9 Ω
5
d) 9 Ω
11

d)
69) When a long straight uniform rod is connected across an
ideal cell, the drift velocity of electrons in it is v. If 73) Three equal resistors, each equal to R, are connected as
a uniform hole is made along the axis of the rod and shown in the following figure; then the equivalent resis-
the same battery is used, then the drift velocity of the tance between points A and B:
electron becomes: [4]
a) < v b) 0
c) V d) > v [4]
a) 2R b) R3
70) In the following figure, the value of resistor to be con- 3
c) R d) 3R
nected between C and D so that the resistance of the
entire circuit between A and B does not change with the 74) In the figure, the equivalent resistance between the points
number of elementary sets used is: A and B is
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75) A current through a wire depends on time as i =α0 t +

βt2 where a α0 = 20 A/s and β = 8 As - 2 . Find the
charge crossed through a section of the wire in 15 s. [4]
a) 11250 C b) 260 C
[4]
c) 2250 C d) 2100 C
a) 8Ω b) 6Ω
c) 4Ω d) 2Ω