SCIENCE
1. In the absence of potential difference in a conductor
(A) electrons do not move
(B) electrons do not accelerate
(C) electrons do not acquire a net momentum
(D) electrons do not have any kinetic energy
ANS : C
2. Electric current is due to drift of electrons in
(A) metallic inductors (B) semiconductors
(C) insulator (D) all the above
ANS : A
3. In metals the time of relaxation of electrons
(A) increases with increasing temperature (B) decreases with increasing temperature
(C) does not depend on temperature (D) changes suddenly at 400 K
ANS : B
4. A steady current is passing through a linear conductor of non-uniform cross-section. The net quantity of charge crossing any cross-section per second is
(A) independent of area of cross-section
(B) directly proportional to the length of conductor
(C) directly proportional to the area of cross-section
(D) inversely proportional to the length of conductor
ANS : A
5. The temperature of a metal wire rises when an electric current passes through it because
(A) collision of metal atoms with each other releases heat energy
(B) collision of conduction electrons with each other releases heat energy
(C) when the conduction electrons fall from higher energy level to lower energy level heat energy is released
(D) collision of conduction electrons with the atoms of metal give them energy which appears as heat
ANS : D
6. There is a current of 4.8 ampere in a conductor. The number of electrons that cross any section normal to the direction of flow per second, is
(A) 1019 (B) 2 1019
(C) 3 1019 (D) 7.68 1020
ANS : C
7. Which of the following statements is true?
(A) Insulators do not contain electrons
(B) Some of the electrons in a conductor are free to move through the material
(C) Conductors always contain more electrons than insulators
(D) The atoms in a conductor can move about but those in an insulator cannot move
ANS : C
8. A current of 5 amp exists in a 10 ohm resistance for 4 min. How many coulomb pass through any cross-section of the resistor in this time?
(A) 12 coulombs (B) 120 coulombs
(C) 1200 coulombs (D) 12000 coulombs
ANS : C
9. A current I flows through the cylindrical conductor. Then, the ratio of potential difference along AB and BC is (A) 1 : 1 (B) 1 : 2 (C) 1 : 4 (D) 1 : 3 |
|
ANS : B
10. Resistivity of a material depends on
(A) temperature (B) electric field
(C) shape of the material (D) size of the material
ANS : A
11. The i-V graph of a conductor at two different temperatures T1 and T2 is given. Then (A) T1 = T2 (B) T1 > T2 (C) T1 < T2 (D) T1 T2 |
|
ANS : C
12. The V-i graph is given for two conductors of same area and length. If 1 and 2 are the conductivities of the conductors 1 and 2 respectively,1/2 = (A) 2 : 1 (B) 3 : 1 (C) |
|
ANS : D
13. The minimum ratio of the resistances between the opposite faces of the rectangular solid conductor is (A) 1 : 9 (B) 1 : 18 (C) 1 : 6 (D) 1 : 12 |
|
ANS : A
14. A wire of length 100 cm carries a steady current i. The potential at the ends of the wire is +5 V and 25 V. The value of potential at x = 30 cm is (A) 6.5 V (B) 11 V (C) 3.5 V (D) 4V |
|
ANS : D
15. The ratio of masses of two aluminum wires is 2 : 1 and their corresponding ratio of lengths is 1 : 2. Then, the ratio of their resistances is
(A) 1 : 4 (B) 2 : 1
(C) 1 : 1 (D) 1 : 8
ANS : D
16. The value of the resistance RAB of the metallic plate is proportional to (A) l (B) t/l2 (C) t-1 (D) l/t |
|
ANS : B
17. A material B has twice the specific resistance of A. A circular wore 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 lB / lA of their respective lengths must be :
(A) 1 (B) 
(C) 
(D) 2
ANS : D
18. Express which of the following set-up can be used to verify ohm’s law?
(A) |
| (B) |
|
(C) |
| (D) |
|
ANS : A
19. When a piece of wire of resistance R is joined end to end with an identical wire, the resistance of the new wire is R1, say; when these wires are joined in parallel the new resistance is R2. Then R1/R2 =
(A) 2 : 1 (B) 4 : 1
(C) 1 : 2 (D) 1 : 1
ANS : B
20. When a wire of resistance R is pulled through in order to double its length, the new resistance of the wire will be
(A) R (B) 3R
(C) 4R (D) 2R
ANS : C
21. The effective resistance between A and B is
(A) R (B) 3R
(C) R/3 (D) none of these
ANS : C
22. Te value of RAB is (A) 9R (B) 4.5R (C) 2R (D) none of these |
|
ANS : C
23. The value of RAB is (A) R (B) R/2 (C) 2R (D) 2R/3 |
|
ANS : B
24. A uniform wire of resistance 20 ohm having resistance 1 /m is bent in the form of a circle as shown in the figure. If the equivalent resistance between M and N is 1.8 , then the length of the shorter section is : |
|
(A) 2 m (B) 5 m
(C) 1.8 m (D) 18 m
ANS : A
25. RAB is equal to : (A) (C) |
|
ANS : D
26. RAB is equal to : (A) R (B) 2R (C) |
|
ANS : C
27. RAB is equal to : (A) 3 (B) 1 (C) |
| |
ANS : D 28. There are N number of resistors each of resistance R connected between the centre and periphery of a (A) NR (B) (C) ANS : D | ||
conducting ring. The effective resistance between A and B is :
29. RAB is equal to : (A) (C) |
|
ANS : D
30. The value of RAB is : (A) R (B) 2R (C) 4R (D) none of these |
|
ANS : A
31. The resistance of the series combination of two resistances is S, when they are joined in parallel, the total resistance is P. If S = nP then the minimum possible value of n is :
(A) 2 (B) 3
(C) 4 (D) 1
ANS : C
32. An electric current is passed through a circuit containing two wires of the same material, connected in parallel. If the lengths and radii are in the raio of 
and 
, then the ratio of the current passing through the wires will be :
(A) 8/9 (B) 1/3
(C) 3 (D) 2
ANS : B
33. The terminal potential difference of the cell of emf and internal resistance r while carrying a current i is (A) – ir (B) + ir (C) ir (D) |
|
ANS : A
34. The terminal voltage between A and B is (A) 6.1 V (B) 5.9 V (C) 6 V (D) zero |
|
ANS : B
35. The terminal voltage between A and B is (A) ir (B) 0 (C) + ir (D) |
|
ANS : B
36. The effective emf between A and B assuming 1 > 2 is (A) 1 (B) 2 (C) |
|
ANS : A
37. The terminal potential difference of a cell is greater than its emf, when it is
(A) being charged (B) on open circuit
(C) being discharged (D) being either charged or discharged
ANS : B
38. Five cells, each of emf E and internal resistance r are connected in series. If due to over sight, one cell is connected wrongly, then the equivalent emf and internal resistance of the combination is
(A) 5E and 5r (B) 3E and 3r
(C) 3E and 5r (D) 5E and 3r
ANS : C
39. A circuit whose resistance R is connected to n similar cells. If the current in the circuit is the same whether the cells are connected in series or in parallel, then the internal resistance r of each cell is given by
(A) r = (R/n) (B) r = nR
(C) r = R (D) r = (1/R)
ANS : C
40. A primary cell has emf 2 volt. When short-circuited it gives a current of 4 amp. Its internal resistance in ohm will be
(A) 0.5 (B) 2
(C) 5 (D) 8
ANS : A
41 To get maximum current through a resistance of 2.5 , one can use m rows of cells, each row having n cells. The internal resistance of each cell is 0.5 . What are the values of n and m if the total number of cells is 45?
(A) m = 3, n = 15 (B) m 5, n = 9
(C) m = 9, n = 5 (D) m = 15, n = 3
ANS : A
42. Two identical cells connected in series send 10 amp current through a 5 resistor. Wen they are connected in parallel, they send 8 amp current through the same resistance. What is the internal resistance of each cell?
(A) zero (B) 2.5
(C) 10 (D) 1.0
ANS : B
43. The terminal potential difference of a cell is greater than its emf, when it is
(A) being charged (B) on open circuit
(C) being discharged (D) being either charged or discharged
ANS : A
44. The value of current I in the given circuit is : (A) 3 A (B) 13 A (C) 23 A (D) –3 A |
|
ANS : B
45. The current in the branch CD in the circuit shown below will (A) I1+I2 (B) I1+I3 (C) I2+I3 (D) I1–I3 ANS : C |
|
46. In the given current distribution, what is the value of I ? (A) 3 A (B) 8 A (C) 2 A (D) 5 A |
|
ANS : C
47. The Kirchhoff’s first law 
and second law 
, where the symbols have their usual meanings, are respectively based on :
(A) conservation of charge, conservation of momentum
(B) conservation of energy, conservation of charge
(C) conservation of momentum, conservation of charge
(D) conservation of charge, conservation of energy
ANS : D
48. The potential difference between A and B in the following figure is
(A) 32 V (B) 48 V
(C) 24 V (D) 14 V
ANS : B
49. If R = 1 , the current in the branch x is (A) very large (B) 0 (C) ½ A (D) indeterminate |
|
ANS : C
50. In the figure shown below the current passing through 6 resistor is : (A) 0.40 amp (B) 0.48 amp (C) 0.72 amp (D) 0.80 amp |
|
ANS : B
51. R = ? (A) 2.5 (B) 3 (C) 2 (D) 1.2 ANS : C |
|
52. The current flowing the through resistance of 2 ohm in the figure is : (A) 1.2 A (B) 1.4 A (C) 0.4 A (D) 1.0 A |
|
ANS : D
53. The magnitude of I in ampere unit is : (A) 0.1 (B) 0.3 (C) 0.6 (D) 0.5
|
|
ANS : A
54. A 3 volt battery with negligible internal resistance is connected in a circuit as shown in the figure. The current i, in the circuit will be : (A) 1 A (B) 1.5 A (C) 2 A (D) 1/3 A |
|
ANS : B
55. The total current supplied to the circuit by the battery is : (A) 4 A (B) 2 A (C) 1 A (D) 6 A |
|
ANS : A
56. The current i drawn from the 5 volt source will be : (A) 0.33 A (B) 0.5 A (C) 0.67 A (D) 0.17 A |
|
ANS : B
57. Find the value of current through 2 resistance for the given circuit is : (A) 5 A (B) 2 A (C) zero (D) 4 A |
|
ANS : C
58. The three resistances of equal value are arranged in the different combinations shown in figure. Arrange them in increasing order of power dissipation :
(I) |
| (II) |
|
(III) |
| (IV) |
|
(A) III < II < IV < I (B) II < III < IV <I
(C) I < IV < III < II (D) I < III < II < IV
ANS : A
59. A resistance of 2 is connected across one gap of a meter-bridge (length of the wire is 100 cm) and an unknown resistance greater than 2 is connected across the other gap. When the resistances are interchanged, the balance point shifts by 20 cm. Neglecting any corrections, the unknown resistance is :
(A) 2.5 (B) 3.2
(C) 7 (D) none of these
ANS : D
60. The length of a wire of a potentiometer is 100 cm,and the emf of its standard cell is E volt. It is employed to measure the emf of a battery whose internal resistance is 0.5 . If the balance point is obtained at l = 30 cm from the positive end, the emf of the battery is :
(where i is the current in the potentiometer wire)
(A) 
(B) 
(C) 
(D) 
ANS : D
61. In a meter bridge experiment 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) 40 cm (B) 80 cm
(C) 50 cm (D) 70 cm
ANS : C
62. In a potentiometer experiment the balancing with a cell is at length 240 cm. On shunting the cell with a resistance of 2 , the balancing length becomes 120 cm. The internal resistance of the coil is :
(A) 0.5 (B) 40
(C) 200 (D) 400
ANS : C
63. In a Wheatstone’s bridge, three resistances P, Q and R connected in the three arms and the fourth arm is formed by parallel combination of S1 and S2 then condition for the bridge to be balanced will be :
(A) 
(B) 
(C) 
(D) 
ANS : B
64 Show in the figure below is a meter bridge set up with null deflection in the galvanometer. The value of the unknown resistor R is : (A) 13.75 (B) 220 (C) 110 (D) 55 |
|
ANS : B
65. In the given circuit, no current is passing through the galvanometer. If the cross-sectional diameter of AB is doubled then for null point of galvanometer the value of AC would : (A) x (B) x/2 (C) 2x (D) none of these |
|
ANS : A
66. In an experiment to measure the internal resistance of a cell by a potentiometer, it is found that the balance point is at a length of 2m, when the cell is shunted by a 5 resistance and at a length of 3 m, when the cell is shunted by a 10 resistance. The internal resistance of the cell is then
(A) 1.5 (B) 10
(C) 15 (D) 1
ANS : B
67. The potential gradient along the length of a uniform wire is 10 volt per metre. B and C are two points at 30 cm and 60 cm on a metre scale along the wire. The potential difference between B and C will be
(A) 3 volt (B) 0.4 volt
(C) 7 volt (D) 4 volt
ANS : A
68. A potentiometer wire has a resistance of 4 ohm and is connected to a cell of steady emf 2 volt and internal resistance of 1 ohm. This potentiometer can measure a maximum voltage of
(A) 2 volt (B) 1.9 volt
(C) 1.6 volt (D) 1.0 volt
ANS : C
69. For a cell of emf 2 V, a balance is obtained for 50 cm of the potentiometer wire. If the cell is shunted by a 2 resistor and the balance is obtained across 40 cm of the wire, then the internal resistance of the cell is
(A) 0.25 (B) 0.50
(C) 0.80 (D) 1.00
ANS : B
70. The potentiometer is more sensitive when
(A) emf of main circuit battery is higher (B) specific resistance of wire is higher
(C) wire is thinner (D) wire is longer
ANS : D
71. For a measuring potential difference a potentiometer is better than a voltmeter because
(A) uses a long wire
(B) works on the principle of Wheatstone bridge
(C) does not disturb the potential difference under measurement
(D) uses a battery of larger emf in the main circuit
ANS : C
72. In the given circuit, the voltmeter records 5 V. The resistance of the voltmeter (in ohms) is : (A)200 (B) 100 (C) 10 (D) 50 ANS : B |
|
73. A voltmeter has resistance G ohms and range V volt. The value of resistance used in series to convert into a voltmeter of range nV is :
(A) nG (B) (n – 1) G
(C) 
(D) 
ANS : B
74. An ammeter has resistance G ohms and a range of I A. The value of parallel shunt resistance connected to the ammeter to increase its range to nIA is :
(A) nG (B) (n – 1) G
(C) (D) 
ANS : D
75. If an ammeter is to be used in place of a voltmeter, then we must connect ammeter with a:
(A) low resistance in parallel (B) high resistance in parallel
(C) high resistance in series (D) low resistance in series
ANS : C
76. An ammeter reads upto 1 ampere. Its internal resistance is 0.81 ohms. To increase the range of 10 amp value of the required shunt is :
(A) 0.03 (B) 0.3
(C) 0.9 (D) 10.0
ANS : D
77. In the circuit, the galvanometer G shows zero deflection. If the batteries A and B have negligible internal resistance, the value of the resistor R will be :
(A) 100 (B) 200
(C) 1000 (D) 500
ANS : A
78. In the circuit shown here the readings of the ammeter and voltmeter are (A) 6 A, 60 V (B) 0.6 A, 6 V (C) (6/11)A, (60/11)A (D) (11/6) A, (11/60) A ANS : D |
| |
79. In the circuit shown, the reading of the voltmeter V is (A) 12 V (B) 8 V (C) 20 V (D) 16 V |
| |
ANS : A
80. Two resistances of 400 and 800 are connected in series with a 6 volt battery of negligible internal resistance. A voltmeter of resistance 10,000 is used to measure the potential difference across 400 . The error in the measurement of potential difference in volts approximately is
(A) 0.01 (B) 0.02
(C) 0.04 (D) 0.05
ANS : C
81. A voltmeter reading upto 1000 mV 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 V (B) 0.001V
(C) 0.1 V (D) 0.01 V
ANS : D
82. In the figure, if the ammeter reads 5 A and voltmeter reads 50 V, then the resistance R is (A) 10 (B) > 10 (C) 5 (D) < 10 |
|
ANS : B
83. A, B and C are voltmeters of resistance R, 1.5 R and 3R respectively. When same potential difference is applied between x and y, the voltmeter readings are VA, VB and VC. Then (A) VA = VB = VC (B) VA VB = VC (C) VA = VB VC (D) VA + VB = VC |
|
ANS : A
84. An ammeter and voltmeter are joined in series to a cell. the readings are x and y respectively. If a resistance is joined in parallel with voltmeter
(A) both x and y will increase
(B) both x and y will decrease
(C) x will decrease and y will increase
(D) x will increase and y will decrease
ANS : D
85. In the given circuit, the voltmeter records 5 V. The resistance of the voltmeter (in ohms) is (A) 200 (B) 100 (C) 10 (D) 50 |
|
ANS : C
86. If cut a wire into two equal parts, for a given voltage compared to its initial power loss, the power dissipation will be
(A) equal (B) halved
(C) doubled (D) four times
ANS : D
87. Two cells of emf 4 V and 6 V are connected to an external load R = ¾ ohm. If = ¼ ohm the power dissipated in the load is (A) 3 J/s (B) 1/3 J/s (C) 1 J/s (D) none of these |
|
ANS : A
88. For maximum power dissipated in the external load of resistance R, R = (A) (C) ANS : D |
|
89 N identical bulbs each of power P are connected in parallel. The total power dissipation is
(A) NP (B) N2P
(C) 
(D) 
ANS : A
90. If N identical bulbs each of power P are connected in series, the total power dissipation is
(A) 
(B)
(C) PN (D) P
ANS : B
91. Two electric bulbs of powers P1 and P2 are connected in parallel; then the effective power of the combination is :
(A) 
(B) 
(C) 
(D) 
ANS : A
92. Two electric bulbs of powers P1 and P2 are connected in series, the effective power is :
(A) 
(B)
(C) (D) P1 + P2
ANS : C
93. Two heater coils when connected separately, boil water in minimum times t1 and t2.when they are connected parallel, the combination takes minimum times t to boil water; then t=
(A) 
(B) 
(C) 
(D) (t2/t1)(t1 + t2)
ANS : C
94. A cell develops same power in the external circuit when connected with two resistors r1 and r2 separately. The internal resistance of the cell is :
(A) 
(B) 
(C) 
(D) 
ANS : A
95. A wire when connected to 220 V mains supply has power dissipation P1. Now the wire is cut into two equal pieces which are connected in parallel to the same supply. Power dissipation in this case is P2. Then P2😛1 is :
(A) 1 (B) 4
(C) 2 (D) 3
ANS : B
96. If in the circuit, power dissipation is 150 W, then R is : (A) 2 (B) 6 (C) 5 (D) 4 |
|
ANS : B
97. A 220 volt, 1000 watt bulb is connected across a 110 volt mains supply. The power consumed will be :
(A) 750 watt (B) 500 watt
(C) 250 watt (D) 1000 watt
ANS : C
98. A 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) four times (B) double times
(C) halved (D) one fourth
ANS : B
99. An energy source will supply will supply a constant into the load if its internal resistance is:
(A) very large as compared to the lad resistance (B) equal to the resistance of the lad
(C) non-zero but less then the resistance of the load (D) zero
ANS : D
100. A 100 W bulb B1 and two 60 W bulb B2 and B3, are connected to a 250 V source, as shown in the figure. Now W1,W2 and W3 are the out put powers of the bulbs B1,B2 and B3 respectively. Then : (A) W1 > W2 = W3 (B) W1 > W2 > W3 (C) W1 < W2 = W3 (D) W1 < W2 < W3 |
|
ANS : B