EXERCISE # 1 NEETIIT.COM. 10. Three copper wires of length and cross sectional area (L, A), (2L, A/2) and (L/2, 2A). Resistance is minimum

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1 CUENT ELECTICITY 1. Specific resistance of a wire depends on its (1) mass (2) length (3) area of cross section (4) None of the above 2. When the temperature increases, the resistance of a wire (1) decreases (2) increases (3) first increases than decreases (4) remains constant 3. There are two wires of the same length and of the same material and radii r and 2r. The ratio of their specific resistance is (1) 1 : 2 (2) 1 : 1 (3) 1 : 4 (4) 4 : 1 4. If the length and cross-section of a wire is doubled, then the resistance will (1) become half (2) increase two times (3) remain unchanged (4) increase four times 5. V-i graph for an ohmic resistance is EECISE # 1 (1) straight line (2) hyperbola (3) parabola (4) circle 6. Three wires each have resistance 2, if we connect 2 in series with one parallel to the combination the equalent resistance is (1) 4/3 (2) 3/4 (3) 6 (4) 3 7. When a resistance wire is passed through a die the cross section area decreases by 1%, the change in resistance of the wire is (1) 1% decrease (2) 1% increase (3) 2% decrease (4) 2% increase 8. When the resistance of copper wire is 0.1 and the radius is 1 mm, then the length of the wire is (specific resistance of copper is ohm x m) (1) 10 cm (2) 10 m (3) 100 m (4) 100 cm 9. There are five resistances of 1 ohm each. If the initial three resistance are joined in parallel and rest two are joined in series, then the final resistance is (1) 3 ohm (2) 8 ohm (3) 7/3 ohm (4) 5 ohm 10. Three copper wires of length and cross sectional area (L, ), (2L, /2) and (L/2, 2). esistance is minimum in (1) wire of cross sectional area (2) wire of area /2 (3) wire of cross sectional area 2 (4) same in all three cases Que For the following circuits, the potential difference between and Y in volt is 2? 3? ? 2? 2 Y (1) 1 (2) 1 (3) 2 (4) 2 Page - 1

2 CUENT ELECTICITY ? 3? 2? 1? Y 13. (1) 2 (2) 3 (3) 6 (4) 9 Y 10? 10? 20V (1) 10 (2) 20 (3) 0 (4) For the following circuits, the potential difference between and Y in volt is 1? 1? 1.5? 20V (1) 0.1 (2) 0.2 (3) 0.3 (4) 0.4 Y 1? 15. The resistance of P, Q, S arms of a Wheatstone bridge are 5, 15, 20 and 60. cell of 4 volt emf and internal resistance is connected with them, then the current flowing (in ampere) is (1) 0.1 (2) 0.2 (3) 1 (4) 2 Question 16 to 26 for following circuits the value of total resistance between and Y in ohm is 16. (Take = 3 ) Y (1) (2) 2 (3) 3 (4) /2 3? 7? 10? 10? 5? Y (1) 2 (2) 3 (3) 4 (4) Y (1) 4 (2) 8 /3 (3) (4) 3 Page - 2

3 CUENT ELECTICITY Y (1) (2) 4 (3) 5 (4) ? 3? 9? Y 4? 6? (1) 5 (2) 3.33 (3) 3 (4) Y (1) 1.5 (2) 2 (3) 3 (4) Kirchoff s first law is based on conservation of : (1) Energy (2) Charge (3) oth (1) & (2) (4) None of these (1) 2 (2) 4 (3) 6 (4) 8 10? 10? 10? Y 10? (1) 10 (2) 20 (3) 30 (4) 7? 25. 3? 10? 10? Y 30? (1) 10 (2) 20 (3) 30 (4) 40 Page - 3

4 CUENT ELECTICITY ? 10? 30? 30? 20? 20? 10? 30? Y (1) 5 (2) 10 (3) 15 (4) Find the equivalent resistance of the following network 2? 2? (1) 4/3 (2) 6/3 (3) 10/3 (4) 8/3 eading of ammeter in ampere for the following circuit is (Q. 28 to 29) ? 12V 3? 6? (1) 4 (2) 3 (3) 1 (4) ? 25? 2? 5? 1.4 (1) 0.4 (2) 1 (3) 0.6 (4) The value of i 1 /i 2 for a given diagram is 4? i 2 P i 1 (1) P? Q? S (2)? S P? Q (3) P? Q? S 4? Q S C i (4)? S P? Q 1? 1? 31. eading of ammeter in ampere for the following circuit is 1.5? 1? 2V Y (1) 0.8 (2) 1 (3) 0.4 (4) 2 Page - 4

5 CUENT ELECTICITY 32. The resistivity of materials is expressed in (1) ohm (2) ohm/meter (3) ohm/meter2 (4) ohm-meter 33. piece of copper wire having resistance is cut into 10 pieces of equal length. These pieces are connected in parallel. The effective resistance of the combination will be (1) (2) (3) 10 (4) The resistance of a wire of cross-section a and length is ohm. The resistance of another wire of the same material and of the same length but cross-section 4a will be (1) 4 (2) (3) (4) wire is stretched to n times its length. Then the resistance now will increase by (1) n times (2) 1/n times (3) n 2 times (4) 1/n 2 times 36. The resistance of wire is ohm. The wire is stretched to half of its diameter. The resistance of the wire will now be (1) 4 (2) 64 (3) /4 (4) ccording to the Kirchoff s laws in any analytic circuit, if the direction of current i is assumed opposite, then the value of current will be (1) i (2) 2 i (3) i (4) zero 38. The potential gradient of a potentiometer wire is defined as (1) the fall of potential per unit length (2) the fall of potential per unit area (3) the fall in potential across the ends of wires (4) None of the above 39. The unit of potential gradient is (1) volt (2) volt/ampere (3) volt/meter (4) volt x meter 40. The unit of potential gradient is similar to (1) resistance (2) current (3) potential (4) intensity of electrical field 41. The length of the potentiometer wire is kept larger so that the value of potential gradient may (1) increase (2) decrease (3) remain uniform all over the length of its wire (4) None of the above 42. For the same potential difference, a potentiometer wire is replaced by another one of a high specific resistance. The potential gradient then ( r = h = 0) (1) decreases (2) remains same (3) increases (4) data is incomplete 43. If the current in a potentiometer increases, the position of the null point will (1) be obtained at a larger length than the previous one (2) be equal to the previous length (3) be obtained at a smaller length than the previous (4) None of the above 44. The sensitivity of a potentiometer is increased by (1) increasing the emf of the cell (2) increasing the length of potentiometer wire (3) decreasing the length of potentiometer wire (4) None of the above Page - 5

6 CUENT ELECTICITY 45. In a potentiometer wire, whose resistance is 0.5 ohm/m, a current of 2 ampere is passing. The value of potential gradient in volt/m will be (1) 0.1 (2) 0.5 (3) 1.0 (4) The 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/m of the wire will be (1) 1.0 (2) 0.2 (3) 0.1 (4) The length of a potentiometer wire is 10 m and a p.d. of 2 volt is applied to its ends. If the length of its wire is increased by 1 m, the value of potential gradient in volt/m will be (1) 0.18 (2) 0.22 (3) 1.3 (4) The ratio of resistance of two wires is 1 : 2. If current in the two is same, the ratio of the potential gradients will be (1) 2 : 1 (2) 1 : 4 (3) 4 : 1 (4) 1 : The potential gradient of potentiometer is 0.2 volt/m. current of 0.1 amp is flowing through a coil of 2 ohm resistance. The balancing length in meters for the p.d. at the ends of this coil will be (1) 2 (2) 1 (3) 0.2 (4) The emf of a standard cell is 1.5 volt and its balancing length is 7.5 m. The balancing length in meters for a 3.5 ohm resistance, through which a current of 0.2, flows will be (1) 3.5 (2) 5.0 (3) 5.7 (4) In the following circuit, the reading in volt of the voltmeter will be 12V Y 40 cm 60 cm 4.8volt (1) 7.2 (2) 4.8 (3) 6 (4) Consider the circuit of figure containing seven resistors. Then the equivalent resistance between points and is G (1) 3 25 (2) (3) In the above circuit(), the effective resistance between points and C is (1) 3 25 (2) (3) In the above circuit(), the effective resistance between points and D is (1) (2) 25 3 (3) 45 8 (4) (4) (4) For the mesh of resistors shown in figure () the effective resistance between and E is (1) 3 25 (2) (3) (4) Page - 6

7 CUENT ELECTICITY 56. For the circuit shown in figure (), the equivalent resistance between points and F is 95 (1) 24 (2) (3) The potential difference between the points and in figure will be (4) None of the above 2 (1) V 3 8 (2) V 9 4 (3) V 3 (4) 2 V 58. The appropriate material to be used in the construction of resistance boxes out of the following is (1) Copper (2) Iron (3) Manganin (4) luminium 59. current of 4.8 is flowing in a conductor. The number of electrons passing through any cross-section per second is (1) (2) (3) (4) The dimensions of a block are 1 cm x 1 cm x 100 cm. If the specific resistance of its material is ohm metre, then the resistance between the opposite rectangular faces is (1) 2 10 (2) 2 10 (3) 2 10 (4) In the circuit diagram shown below, the magnitude and direction of the flow of current respectively would be (1) 3 7 amp. from a to b via e (2) 3 7 amp. from b to a via e (3) 1.0 amp. from b to a via e (4) 1.0 amp. from a to b via e 62. What is the equivalent resistance in ohms between points and? (1) 15.4 (2) 2.7 (3) 12.0 (4) coil has a resistance of 50 and 20 0 C. t 40 0 C, its resistance becomes 51. The temperature coefficient of the wire at 20 0 C is (1) 0.01 (2) (3) (4) Which of the following statement is true both for a series and a parallel d.c. circuits? (1) Powers are additive (2) Voltages are additive (3) Currents are additive (4) None of the above Page - 7

8 65. If each resistance in the figure is 9 ohm, then reading of the ammeter is CUENT ELECTICITY (1) 5 (2) 8 (3) 2 (4) For what value of unknown resistance, the potential difference between and D will be zero in the arrangement of figure shown. (1) 4 ohm (2) 2 ohm (3) 3 ohm (4) 6 ohm 67. cell is balanced at 100 cm of a potentiometer wire when the total length of the wire is 400 cm. If the length of the potentiometer wire is increased by 100 cm, then the new balancing length for the cell will be (1) 100 cm (2) 125 cm (3) 80 cm (4) 250 cm 68. current of 2 amp is flowing in the primary circuit of a potentiometer wire having resistance of 0.2 ohm/m. In a coil when current of 1 flows, then potential difference across its terminals are balanced at 2.5 m of the potentiometer wire. The resistance of the coil is (1) 1 ohm (2) 2.5 ohm (3) 0.4 ohm (4) 5.0 ohm 69. Two wires of same dimension but resistivities 1 and 2 are connected in series. The equivalent resistivity of the combination is (1) (2) 1/2 ( ) (3) 1 2 (4) 2( ) 70. cell of e.m.f. E is connected across a resistance r. The potential difference between the terminals of the cell is found to be V. The internal resistance of the cell must be (1) 2(E V)V r (2) 2(E V)r E (3) ( E V)r V NSWE KEY (4) (E V) r Q ns Q ns Q ns Q ns Q ns Page - 8

9 EECISE # 2 CUENT ELECTICITY 1. There are eight resistances of ohm each. Two-two resistances are connected in parallel to form couples and these couples are connected in series, then the total resistance of this combination is : [MP PET 87] (1) 2 (2) 2 (3) 4 (4) 8 2. eading of ammeter in ampere for the following circuit is : (1) 1 (2) 1 2 2V i V (3) For the following circuit the potential difference between x and y in volt is : V x DC V 100 [PET 87] y (4) 3 (1) 10 (2) 50 (3) 100 (4) 0 4. The value of total resistance between x and y in ohm is : x y [PET 87] [PET 87, MP PMT 99] C (1) (2) 3 (3) 4 (4) 5 Page - 9

10 CUENT ELECTICITY 5. The following diagram shows the circuit for the comparision of e.m.f. of the cells. The circuit can be corrected by: [PET 88] E h E 1 (1) eversing the terminals of E (2) eversing the terminals of E 1 (3) eversing the terminals of E 2 (4) eversing the current in h. E 2 6. Two similar cells are connected first in series and then in parallel, the ratio of balancing length on the potentiometer wire will be : (1) 1:2 (2) 2:1 (2) 1 : 4 (4) 4 : 1 7. In the following circuit, the reading of the voltmeter will be : (in volt) (1) 7.2 (2) 4.8 (3) 6 (4) 4 12V 40cm 4.8V G h V 60cm 8. The resistance of a wire is 50 ohm Then the graph between log V and log I is : (1) straight line (2) parabola (3) hyperbola (4) circle G [PMT 88] [PET 88] [PET 89] 9. The resistance of wire is 20 ohm. The wire is stretched to three times of its length.. Then the resistance will be : (1) 6.67 (2) 60 (3) 120 (4) 180 [MP PET 89, 2001, PMT 2001] 10. In the following diagram, the deflection in the galvanometer in a potentiometer circuit is zero, then : (1) E 1 > E 2 E h [PET 90] (2) E 2 > E 1 (3) E 1 = E 2 (4) E 1 + E 2 = E E 1 E 2 G G Page - 10

11 CUENT ELECTICITY 11. In the following circuit, the resistance of a voltmeter is 10,000 and that of an ammeter is 20. If the reading of an ammeter is 0.1 amp. and that of voltmeter is 12 volt, then the value of is : (1) 122 (2) 100 (3) 118 (4) 116 V 12. Value of Current i in the following circuit is : (1) 13 (2) (3) 9 (4) none of the above Which of the following wires of the same material will have higher resistance : i (1) radius is 1 mm and the length is 40 m. (2) radius is 2 mm and the length is 40 m. (3) radius is 1 mm and the length is 80 m. (4) radius is 2 mm and the length is 80 m. [PET 90] [PET 90] [PET 91] 14. The resistance of galvanometer is G ohm and the range is 1 volt. The value of resistance used to convert it into a voltmeter of range 10 volt is : (1) 9G (2) G (3) 1 9 G (4) 10 G [PET 91] 15. The total resistance between x and y in ohm is : [PET 91] (1) 1 (2) 4 (3) (4) The reading of mmeter in ampere for following circuit is : x 8 6 y (1) [PET 92] (2) 1.5 (3) zero (4) 2 8 2V Page - 11

12 CUENT ELECTICITY 17. The emf of a standard cell is balanced at 150 cm length of a potentiometer wire. When this cell is shunted by a 2ohm resistance, the null point is obtained at 100 cm. The value of internal resistance of the cell is : (1) 0.1 ohm (2) 1 ohm (3) 2 ohm (4) 0.5 ohm [MP PET 93] 18. There are two wires of same material but length and diameter of first wire are double of the second wire. Then the resistance of first wire will be : [MP PMT 93] (1) double of the resistance of the second wire. (2) half of the resistance of the second wire. (3) equal to the resistance of the second wire. (4) fourth times the resistance of the second wire. 19. If the length of the wire is doubled, then the specific resistance will be : [PMT 93] (1) two times (2) 1 2 times (3) foure times (4) same 20. The resultant resistance of n resistance wires each of r ohm is, when they are connected in parallel. When these n resistance are connected in series, the resultant resistance will be : [PMT 93] (1) n (2) 2 n (3) n (4) n galvanometer of resistance 100 gives full deffection for a current The value of shunt required to convert it into a ammeter of range 1 ampere, is : [MP PMT 93] (1) 1 (2) 10 3 (3) 1 5 (4) % of the main current passes through the galvanometer. If the resistance of the galvanometer is G, then the resistance of the shunt will be : [NCET 90, PET 93] (1) G 50 (2) G 4 (3) 50G (4) 9G 23. Kirchhoff 's first and second law shows the conservation of : [MP PET 93, PET 2001] (1) linear momentum and angular momentum. (2) charge and energy. (3) mass and energy. (4) charge and linear momentum. 24. Four resistances are connected in a circuit as shown in the following diagram.the value of the current in ampere in 4ohm and 6ohm resistance are : [MP PET 93] (1) 2 and 4 (2) 1 and 2 (3) 1and 1 (4) 2 and 2 20V In the following circuit diagram the value of resistance for the potential difference between and D is zero : [MP PET 93] (1) 4 ohm (2) 6 ohm (3) 8 ohm (4) 9 ohm D 3 C Page - 12

13 CUENT ELECTICITY 26. The e.m.f. of a cell is 2.0 volt and the internal resistance is 0.1ohm. It is connected with a resistance of 3.9ohm. Then potential difference across the cell is : [MP PET 93, PMT 2000] (1) 0.20V (2) 1.90 V (3) 1.95 V (4) 2.00 V 27. In the following circuit the resultant e.m.f. between is : E 3 E 1 E 2 E 3 (1) E 1 +E 2 +E 3 +E 4 (2) E 1 +E 2 +2E 3 +E 4 (3) E +E + E E E (4) E 4 1 +E E The sensitivity of a potentiometer is increased by (1) increasing the emf of the cell. (2) increasing the length of the potentiometer wire. (3) decreasing the length of potentiometer wire. (4) none of the above. E 4 [MP PET 94] 29. potential gradient is created in the wire by a standared cell for the comparision of emf's of two cells in a potentiometer experiment. Which possibility of the following will cause failure of the experiment. (1) the emf of the standard cell is higher than that of the other cells. (2) the diameter of the wires is equal and similar, (3) the number of wires is ten. (4) the emf of the standard cell is less than those of both the cells. [MP PMT 94] 30. voltmeter of 998 ohm resistance is connected to a cell of emf 2 volt, having internal resistance of 2 ohms, The error in measuring emf will be : [MP PMT 94] (1) V (2) V (3) V (4) V 31. The specific resistance of a metal wire is cm., the length is 198 cm and the resistance is 7. The radius of wire is : [MP PET 94] (1) 2.4 cm (2) 0.24 cm (3) cm (4) 24 cm 32. Which of the following statement is wrong : (1) the resistance of a voltmeter is high. (2) the resistance of an ammeter is low. (3) an ammeter is connected in parallel with a conductor in the circuit. (4) a voltmeter is connected in parallel with a resistance in the citcuit. [MP PET 94] Page - 13

14 CUENT ELECTICITY 33. The resistance of the galvanometer is 25 it gives a full scale deflection when a current of 10m is passed through it. The value of resistance used in series to convert it into voltmeter of range 100 volt is : (1) 10,000 (2) (3) 975 (4) 9975 [MP PET 94] 34. Which of the statment is wrong : [MP PMT 94] (1) when all resistance are equal, then the sensitivity of wheatstone bridge is maximum. (2) when the galvanometer and the cell are interchanged, then the balancing of wheat stone bridge will be effected. (3) Kirchoff's first law for the currents meeting at the Junctions in an electric circuit shows the conservation of charge. (4) heostat can be used as potential divider. 35. In a meter bridge the null point is obtained at the middle point of the wire. If in one gap the resistance is 10, then the value of resistance in the other gap is : [MP PET 94] (1) 10 (2) 5 (3) 1 5 (4) new electric store house of 1.5 emf of a flash gives a current of 15, when it is connected with an electric ammeter of 0.0, then the value of internal resistance of the electric store house is : [MP PET 94] (1) 0.04 (2) 0.06 (3) 0.10 (4) In a torch there are two cells each of 1.45 volt and Each cell gives a current to filament of a lamp of 1.5, then the value of current in ampere is : [MP PET 94] (1) (2) (3) (4) In a potentiometer experiment a voltage source is balanced at 60cm length where as a 3 volt battery is balanced at 45cm length. What is the voltage of unknown voltage source : [PMT 95] (1) 3V (2) 4V (3) 4.5V (4) 6V 39. potential difference V is applied across a copper wire of diameter d and length L. when only d is doubled, the drift velocity : [MP PMT 95] (1) increases two times (2) decreases 1 2 times (3) does not change (4) decreases 1 4 times 40. Find the potential difference between and Y in volt is : [PET 95] Y 2 2 (1) 1 (2) 1 (3) 2 (4) 2 Page - 14

15 CUENT ELECTICITY 41. cell of e.m.f. 2V and negligible internal resistance is connected to resistor 1 and 2 as shown in the figure. The resistance of the Voltmeter, 1 and 2 are 80, 40 and 80 respectively. The reading of the Voltmeter is : [HU 95] (1) 1.78 V (2) 1.60 V (3) 0.80 V (4) 1.33 V 2V E V Potentiometer wire length is 10 m, having a total resistance of 10 If a battery of emf 2 volt (negligible internal resistance) and a rheostat is connected to it then potential gradient is 20mV/m find the resistance applied through rheostat : [PMT 96] (1) 90 (2) 990 (3) 40 (4) In a potentiometer, a standard cell of 1.1V is balanced through a length of 7.04m For calibration of ammeter the resistance of 1 is balanced through a length of 0.64m if the reading of ammeter is 0.11amp. Then error in measurment is... [PMT 96] (1) 0.01 (2) 0.01 (3) 1.0 (4) When a voltmeter is conected across the terminals of a cell, it measure 9 Volt. If a resistance of 1.5 is connected across the terminals of a cell as shown in figure. Then current flowing through this resistance is : V 9V =1.5 (1) 1.3 (2) 6 (3) 9 (4) 12 [HU 96] 45. The resistance of a coil in a platinum resistance thermometer at 0 C is 5 ohm and at 100 C it is 5.75 ohm. Its resistance at an unknown temperature is 5.15 ohm. Then the unknown temperature will be : (1) 40 C (2) 10 C (3) 15 C (4) 20 C [HU 97] 46. Eight identical cells each of potential E and internal resistance r are connected in series to form a closed circuit. n ideal voltmeter connected across 2 cells will read : [HU 97] (1) 13 E (2) zero (3) 2 E (4) 10 E 47. P, Q is a uniform wire of resistance 2000 and M the mid point of PQ. voltmeter of resistance 1000 is connected between P and M. The reading of the voltmeter, when, the potential difference applied between PQ is 150 volt will be. [KCET 97] (1) 150 volt (2) 100 volt (3) 75 volt (4) 50 volt P V M Q Page - 15

16 CUENT ELECTICITY 48. Two rods and made up of same metal have same length. The ratio of their resistances is 1 : 2. If these rods are immersed in water then loss in weight will be : [PMT 97] (1) more in (2) more in (3) same is and (4) in the ratio 1 : student connects a voltmeter, ammeter and resistance according to the circuit given. If the voltmeter reading is 20 V and ammeter reading is 4, then the resistance will be : [PMT 97, JIPME 99] (1) equal to 5 (2) more than 5 (3) less than 5 (4) more of less depending on the material of wire 50. potentiometer wire of 10 m length and having a resistance of 1 ohm/m is connected to an accumulator of emf 2.2 volt and a high resistance box. To obtain a potential gradient of 2.2mV/m, the value of resistance used from the resistance box is : [PET 97] (1) 790 ohm (2) 810 ohm (3) 990 ohm (4) 1000 ohm 51. For two wires and of same material and of same mass, the radius of is double that of. If the resistance of wire is 34 then that of will be : [PET 97] (1) 544 (2) 272 (3) 68 (4) In the following circuit if V V = 4V, then the value of resistance in ohms will be : [PET 97] (1) 5 (2) 10 (3) 15 (4) V 5V 53. For the network of resistance shown in the fig. the equivalent resistance of the network between the points and is 18. The value of unknown resistance is : [PET 97] (1) 8 (2) 10 (3) 16 (4) When a potential difference is applied across the ends of a linear metallic conductor : [MP PET 97] (1) the free electrons are accelerated continuously from the lower potential end to the higher potential end of the conductor (2) the free electrons are accelerated continuously from the higher potential end to the lower potential end of the conducotr (3) the free electrons acquire a costant drift velocity from the lower potential end to the higher potential end of the conductor. (4) the free electrons are set in motion from their position of rest 10 Page - 16

17 CUENT ELECTICITY 55. current of 2 is flowing through a cell of e.m.f. 5 V and internal resistance 0.5 from negative to positive electrode. If the potential of negative electrode is 10 V, the potential of positive electrode will be : (1) 5 V (2) 14 V (3) 15 V (4) 16 V [MP PMT 97] cells, each of e.m.f. 5 V and internal resitance 1, are to be arranged so as to produce maximum current in a 25 resistance. Each row is to contain equal number of cells. The number of rows should be : [MP PMT 97] (1) 2 (2) 4 (3) 5 (4) In the circuit shown below, the cell has an e.m.f. of 10 V and internal resistance of 1. The other resistances are shown in the fig. The potential difference V V is : [MP PMT 97] E=10V r=1 (1) 6 V (2) 4 V (3) 2 V (4) 2 V Two resistance 1 and 2 are made of different materials. The temperature coefficient of the material of 1 is and of the material of 2 is. The resistance of the series combination of 1 and 2 will not change with temp., then ratio of resistance of two wire at 0 C will be : [MP PMT 1997] (1) (2) (3) (4) 59. In the arrangment of resistances shown below. The effective resistance between points and is [MP PMT 1997] (1) 20 (2) 30 (3) 90 (4) resistance of 4 and a wire of length 5 m and resistance 5 are joined in series and connected to a cell of e.m.f. 10V and internal resistance 1. Parallel combination of two identical cells is balanced across 300 cm of the wire. The e.m.f. E of each cell is : [MP PMT 1997] 10V,1 E 3m 5,5m E G (1) 1.5 V (2) 3.0 V (3) 0.67V (4) 1.33 V Page - 17

18 CUENT ELECTICITY 61. The resistance of a galvanometer is 50 and the current required to give full scale deflection is 100. In order to convert it into an ammeter, reading upto 10, it is necessary to put a resistance of : (1) in parallel (2) in parallel(3) 10 5 in series (4) 99, 950 in series 62. The resistivity of a wire depends on its : (1) length (2) area of cross section (3) shape (4) material [MP PMT 1997] [MP PET/PMT 1998] 63. The conductivity of a super conductor is : (1) infinite (2) very large (3) very small (4) zero 64. Electromotive force of a cell is basically a (1) force (2) power (3) work (4) current capacity [MP PET/PMT 98] [HU 98] 65. battery of 10 V and internal resistance 0.5 is conneted across a variable resistance. The value of for which the power delivered in its maximum state, is equal to : (1) 0.5 (2) 1 (3) 1.5 (4) 2 [HU 98] 66. galvanometer has a resistance G and current i a flowing in it, produces full scale deflection. If S 1 is the value of shunt which converts it into an ammeter of range 0 i and S 2 is the value of the shunt for the range 0 2i. Then the ratio S S 1 2 will be : 1 i ia (1) 1 (2) 2 (3) 2 2i ia 2i ia (4) i ia [KCET 98] 67. esistance of a galvanometer coil is 8 and 2 shunt resistance is connected with it. If main current is 1 then the current flow through 2 resistance will be %& (1) 0.2 (2) 0.8 (3) 0.1 (4) Which of the following is scalar : (1) current (2) velocity (3) force (4) acceleration [IPMT 98] [PMT 99] 69. In a Neon discharge tube Ne + ions move to the right each second, while electrons move to the left per sec., electron charge is C. The current in the discharge tube : [MP PET 99] (1) 1 towards right (2) 0.66 towards right (3) 0.66 towards left (4) zero 70. Constanton wire is used in making standard resistances, because its : (1) specific resistance is low (2) density is high (3) temperature coeff. of resistance is negligible (4) melting point is high [MP PET 99] Page - 18

19 CUENT ELECTICITY 71. When a resistance of 2 ohm is connected across the terminals of a cell, the current is 0.5. When the resistance is increased to 5 ohm, the current is The e.m.f. of the cell is : (1) 1.0 V (2) 1.5 V (3) 2.0 V (4) 2.5 V [MP PMT 99] 72. Two nonideal batteries are connected in parallel consider the following statements : [MP PMT 99] () The equivalent emf is smaller than either of the two emfs () The equivalent internal resistance is smaller than either of the two internal resistances (1) both and are correct (2) is correct but is wrong (3) is correct but is wrong (4) both and are wrong 73. Equivalent resistance of series combination : (1) is equals to mean of individual resistors (2) is less than the lesser one (3) is in between the smaller and bigger resistors (4) is sum of individual resistors 74. The net resistance of a voltmeter should be large to ensure that : (1) it does not get over heated (2) it does not draw excessive current (3) it can measure large potential difference (4) it does not appriciably change the potential difference to be measured 75. The current in 8 resistance is (as per given circuit) (1) 0.69 (2) 0.92 (3) V 8 6V 6 E 6 [MP PMT 99] [MP PMT 99] [IPMT 99] (4) The value of for which power in it is maximum (1) 3 (2) 6 (3) 12 (4) 9 [IPMT 99] 77. The current conduction in a discharge tube is due to : [IPMT 99] (1) electrons only (2) + ve ions and ve ions (3) ( ve) ions and electrons (4) (+ ve) ions and electrons Page - 19

20 78. If each resistance in the fig. is of 9 then reading of ammeter is : CUENT ELECTICITY [PMT 2000] 9V (1) 5 (2) 8 (3) 2 (4) In fig. battery E is balanced on 55 cm length of potentiometer wire but when a resistance of 10 is connected in parallel with the battery then it balances on 50 cm length of the potentiometer wire then internal resistance r of the battery is : [PET 2000] (1) 1 (2) 3 (3) 10 (4) If i = 0.25 amp. in fig then value of is : (1) 48 (2) 12 (3) 120 (4) 42 E i 12V 2V r 1m [PET 2000] 81. car battery of e.m.f. 12V and internal resistance , receives a current of 60 from an external source, then terminal potential difference of battery is : [IPMT 2000] (1) 32 V (2) 10 V (3) 15 V (4) 50 V 82. copper wire stretched so as to make it 0.1% longer. The percentage increase in the resistance of the wire is : (1) 1.0 (2) 2.0 (3) 0.1 (4) 0.2 [MP PMT 2000] ,000 electrons are passing per minute through a tube of radius 1cm. The resulting current is : [MP PET 2000] (1) (2) (3) 10 9 (4) Seven resistances are connected as shown in the figure.the equivalent resistance between and is : [MP PET 2000] (1) 3 (2) 4 (3) 4.5 (4) 5 Page - 20

21 CUENT ELECTICITY 85. t what temperature will the resistance of a copper wire become three times its value at 0 C [Temperature coefficient of resistance for copper = per C] : (1) 400 C (2) 450 C (3) 500 C (4) 500 C [MP PET 2000] 86. In the circuit shown below, the internal resistance of the battery is 1.5 and V P and V Q are the potentials at P and Q respectively, what is the potential difference between the points P and Q : [MP PET 2000] (1) zero (2) 4 volt (V p > V Q ) (3) 4 volt (V Q > V P ) (4) 2.5 volt (V Q > V P ) 20V, Two cells, each of e.m.f. E and internal resistance r, are connected in parallel across a resistor. The power dissipated in the resistor is maximum if : [MP PET 2000, 2001 JIPME 95, MU 2002] 3r r (1) = r (2) = 2r (3) (4) cylindrical wire is stretched such that its length gets doubled but volume remains same, the resistance of wire becomes : [PMT 2000] (1) four times (2) remains same (3) half (4) becomes double 89. In a network as shown in the figure the potential difference across the resistance 2 is (the cell has an emf of E and has no internal resistance) : (1) 2E (2) 4E 7 (3) E P Q E [HU 2000] (4) E 90. There are free electrons per cm 3 in copper. The current in the wire is 0.21 (e = C). Then the drifts velocity of electrons in a copper wire of 1 mm 2 cross section, will be : (1) m/s (2) m/s (3) m/s (4) none of these [HU 2000] 91. In a typical Wheatstone network the resistance in cyclic order are = 10, = 5, C = and D = 4 for the bridge to be balanced. [KCET 2000] =10 =5 D= C= (a) 10 should be connected in parallel with (b) 10 should be connected in series with (c) 5 should be connected in series with (d) 5 should be connected in parallel with (1) a, b (2) b, c (3) a, c (4) all Page - 21

22 CUENT ELECTICITY 92. In the circuit shown here, what is the value of the unknown resistor so that the total resistance of the circuit between points 'P' and 'Q' is also equal to : [MP PET 2001] (1) 3 (2) 39 (3) P 3 Q 3 (4) battery has e.m.f. 4V and internal resistance 'r'. When this battery is connected to an external resistance of 2 ohms, a current of 1 amp. flows in the circuit. How much current will flow if the terminals of the battery are connected directly : (1) 1 (2) 2 (3) 4 (4) infinite [MP PET 2001] 94. In the circuit shown here, E 1 = E 2 = E 3 = 2V and 1 = 2 =4 ohms. The current flowing between points and through battery E 2 is : E 1 E 2 1 E 3 2 (1) zero (2) 2 amp from to (3) 2 amp from to (4) none of the above [MP PET 2001] 95. is a potentiometer wire of length 100 cm and its resistance is 10 ohm. It is connected in series with a resistance = 40 ohm and a battery of e.m.f. 2V and negligible internal resistance. If a source of unknown e.m.f. E is balanced by 40 cm length of the potentiometer wire, the value of E is: [MP PET 2001] (1) 0.8 V (2) 1.6 V (3) 0.08 V (4) 0.16 V 96. Three resistance of values 2, 3 and 6 are to be connected to produce an effective resistance of. This can be done by connecting : 40cm E (1) 3 resistance in series with the parallel combination of 2 and 6 (2) 6 resistance in series with the parallel combination of 2 and 3 (3) 2 resistance in series with the parallel combination of 3 and 6 (4) 2 resistance in parallel with the parallel combination of 3 and 6 2V [KCET 2001] 97. battery of electro motive force E is connected in series with a resistance and a voltmeter. n ammeter is connected in parallel with the battery [KCET 2001] (1) neither the ammeter nor the voltmeter will be damaged. (2) both ammeter and voltmeter are likely to be damaged. (3) only voltmeter is likely to be damaged. (4) only ammeter is likely to be damaged. Page - 22

23 CUENT ELECTICITY 98. Two resistance wires on joining in parallel the resultant resistance is 6 ohm. One of the wire breaks, the 5 effective resistance is 2 ohm. The resistance of the broken wire was : [MP PMT 2001, JIPME 98] (1) 3 5 ohm (2) 2 ohm (3) 6 5 ohm (4) 3 ohm 99. The temperature coefficient of resistance of a wire is per degree celcius. t 300 K its resistance is 1 ohm. The resistance of the wire will be 2 ohm at following temperature : [MP PMT 2001] (1) 1154 K (2) 1127 K (3) 600 K (4) 1400 K 100. If specific resistance of a potentiometer wire is 10 7 m and current flow through it is 0.1 amp., cross sectional area of wire is 10 6 m 2 then potential gradient will be : [IPMT 2001] (1) 10 2 volt/m (2) 10 4 volt/m (3) 10 6 volt/m (4) 10 8 volt/m 101. The resistance of each arm of the wheat stone bridge is 10. resistance of 10 is connected in series with galvanometer then the equivalent resistance across the battery will be : [IPMT 2001] (1) 10 (2) 15 (3) 20 (4) Copper and silicon are cooled from 300 K to 60K, the specific resistance : [IPMT 2001] (1) decrease in copper but increase in silicon (2) increase in copper but decrease in silicon (3) increase in both (4) decrease in both 103. There is a current of 40 ampere in a wire of 10 6 m 2 area of cross-section. If the number of free electron per m 3 is 10 29, then the drift velocity will be : [PUNJ PMT 2001] (1) m/s (2) m/s (3) m/s (4) m/s 104. n ammeter and a voltmeter are joined in series to a cell. Their readings are and V respectively. If a resistance is now joined in parallel with the voltmeter : [KCET 2002] (1) voth and V will decrease. (2) both and V will increase. (3) will increase, V will decrease. (4) will decrease, V will increase cell supplies a current of 0.9 through a 2 resistor and a current of 0.3 through a 7 resistor. The internal resistance of the cell is : [KCET 2002] (1) 1.0 (2) 0.5 (3) 2.0 (4) The current voltage graph for a given metallic conductor at two different temperatures T 1 and T 2 are as shown in the figure. Then : [KCET 2002, MU 2004] I T 1 T 2 V (1) T 1 > T 2 (2) T 1 = T 2 (3) nothing can be said about T 1 and T 2 (4) T 1 < T galvanometer of 100 resistance gives complete deflection on flowing 10 m current. What should be the value of shunt so that it can measure 100 m : [MP PET 2002] (1) (2) 9.9 (3) 1.1 (4) 4.4 Page - 23

24 CUENT ELECTICITY 108. For changing the range of a galvanometer with G ohm resistance from V volt to nv, what will be the value of resistance connected in series to it : [MP PET 2002] (1) (n 1)G (2) G n (3) ng (4) G n Specific resistance of a conductor increases with : [IPMT 2002] (1) increase in temperature. (2) increase in cross section area (3) increase in cross section and decrease in length. (4) decrease in cross section area For a cell terminal potential difference is 2.2 V when circuit is open and reduces to 1.8 V when cell is connected to a resistance of = 5 then determine internal resistance of cell is : [IPMT 2002] (1) 10 9 (2) 9 10 (3) 11 9 (4) To convert a galvanometer into a voltmeter one should connect a : (1) high resistance in series with galvanometer. (2) low resistance in series with galvanometer. (3) high resistance in parallel with galvanometer. (4) low resistance in parallel with galvanometer. [IPMT 2002] 112. N identical cells whether joined together in series or in parallel, give the same current, when connected to an external resistance of ''. The internal resistance of each cell is : (1) r = n (2) r = (3) r = n (4) r = n 2 [PMT 2002] 113. The potential difference between the points and in the following circuit shown in the figure : [PMT 2002] 5 2V 5 (1) 2 volt 3 (2) 4 volt (3) 8 volt 9 (4) 2 volt 114. In the potentiometer experiment if deflection in galvanometer is measured zero then current will become zero in: (1) potentiometer wire (2) galvanometer circuit (3) main circuit (4) cell [PMT 2002] 115. Length of a potentiometer wire is kept more and uniform to achive : [PMT 2002] (1) uniform and more potential gradient (2) non-uniform and more potential gradient (3) uniform and less potential gradient (4) non-uniform and less potential gradient Page - 24

25 CUENT ELECTICITY 116. The balancing length is obtained at 78.4 cm length while measuring the potential difference at the ends of a resistance wire. When same potential difference is measured with a voltmeter, it shows 1.20 volt. If a standard cell of emf volt is balanced at 63.2 cm, the error in voltmeter reading in volt will be : (1) 0.06 (2) (3) 0.03 (4) [PMT 2002] 117. Consider four circuits shown in the figure below. In which circuit power dissipated is greater (Neglect the internal resistance of the power supply) : [OISS JEE 2002] (1) E (2) 118. The equivalent resistance across is : E (3) E (1) 1 (2) 2 (3) 3 (4) (4) E [OISS JEE 2002] 119. There are three voltmeters of the same range but of resistance 10000, 8000 and 4000 respectively. The best voltmeter among these is the one whose resistance is : [KEL PET 2002] (1) (2) 8000 (3) 4000 (4) all are equally good 120. When a voltmeter and an ammeter are connected respectively across the terminals of a cell, measures 5 V and 10. Now only a resistance of 2 is connected across the terminal of the cell. The current flowing through this resistance is : (1) 7.5 (2) 5.0 (3) 2.5 (4) 2.0 [JIMPE 2003] 121. Thirteen resistance each of resistance ohm are connected in the circuit as shown in the figure. The effective resistance between and is : (1) 4 3 (2) 2 (3) [KCET 2003] (4) 2 3 Page - 25

26 CUENT ELECTICITY 122. group of N cells whose emf varies directly with the internal resistance as per the equation E N = 1.5 r N are connected as shown in the figure. The current I in the circuit is (1) 5.1 (2) 0.51 (3) 1.5 (4) 0.15 N r 1 r N r 3 r [KCET 2003] 123. galvanometer has resistance 36. If a shunt of is added with this, then fraction of current that passes through galvanometer is : (1) 1 4 (2) 1 9 (3) 1 10 r (4) 1 40 [PMT 2003] 124. If 10 6 electrons/s are flowing through an area of cross section of 10 4 m 2 then the current will be : (1) (2) (3) (4) [PMT 2003] 125. The terminal voltage is E when a current of 2 is flowing through 2 resistance, then the internal resistance of 2 cell is : (1) 1 (2) 2 (3) 3 (4) 4 [PMT 2003] voltmeter has range 1V. Find the additional resistance which has to join in series in voltmeter to increase the range of voltmeter to 100 V : (1) 10 (2) 1 (3) 99 (4) [PMT 2003] 127. The 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 : [IEEE 2003] (1) 300% (2) 200% (3) 100% (4) 50% 128. 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 e.m.f. of a battery whose internal resistance is 0.5. If the balance point is obtained at = 30 cm from the positive end, the e.m.f. of the battery is : [IEEE 2003] (1) 30E 100 (2) 30E (3) 30E ( ) (4) 30(E 0.5) 100 Page - 26

27 CUENT ELECTICITY 129. Three unequal resistors in parallel are equivalent to a resistant 1 ohm. If two of them are in the ratio 1 : 2 and if no resistance value is fractional, the largest of the three resistance in ohms is : [EMCET 2003] (1) 4 (2) 6 (3) 8 (4) Express which of the following setups can be used to verify Ohm's law : [IIT SC. 2003] h V (1) E h (3) V E V (2) E h (4) E 131. In the shown arrangement of the experiment of the meter bridge if C corresponding to null deflection of galvanometer is x, what would be its value if the radius of the wire is doubled : [IIT SC. 2003] (1) x (2) x 4 (3) 4x (4) 2x h The current in a conductor varies with time t as I = 2t + 3t 2 amp. where I is ampere and t in second. Electric charge flowing through a section of the conductor during t = 2 sec to t = 3 sec is : [OISS JEE 2003] (1) 10 C (2) 24 C (3) 33 C (4) 44 C 133. If the ammeter in the given circuit reads 2, the resistance is : [OISS JEE 2003] (1) 1 ohm (2) 2 ohm (3) 3 ohm (4) 4 ohm 134. esistance in the two gaps of a meter bridge are 10 ohm and 30 ohm respectively. If the resistances are interchanged the balance point shifts by : [OISS JEE 2003] (1) 33.3 cm (2) cm (3) 25 cm (4) 50 cm x 3 6 C G 6V V Two wires of resistance 1 and 2 at 0 C have temperature coefficient of resistance 1 and 2, respectively. These are joined in series. The effective temperature coefficient of resistance is : [MP PET 2003] (1) (2) 1 2 (3) (4) Page - 27

28 136. In the circuit shown below. The reading of the voltmeter V is : CUENT ELECTICITY [MP PET 2003] 2 h + V (1) 12 V (2) 8 V (3) 20 V (4) 16 V 137. The equilvalent resistance and potential difference between and for the circuit is respectively : [JIMPE 2004] 2.5 (1), 8V (2) 8, 4V (3) 2, 2 V (4) 16, 8V 138. n unknown resistance 1 is connected in series with a resistance of 10. This combination is connected to one gap of a metre bridge while a resistance 2 is connected in the other gap. The balance point is at 50 cm. Now, when the 10 resistance is removed the balance point shifts to 40 cm. The value of 1 is (in ohms) : (1) 20 (2) 10 (3) 60 (4) 40 [KCET 2004] 139. The electric resistance of a certain wire of iron is. If its length and radius both are doubled, then : (1) the resistance will be halved and the specific resistance will remain unchanged (2) the resistance will be halved and the specific resistance will be doubled (3) the resistance and the specific resistance, will both remain unchanged (4) the resistance will be doubled and the specific resistance will be halved 140. galvanometer acting as a voltmeter will have : [IPMT 2004] [IPMT 2004] (1) a high resistance in series with its coil (2) a low resistance in parallel with its coil (3) a low resistance in series with its coil (4) a high resistance in parallel with its coil 141. bullet of mass 2 g. is having a charge of 2 C. Through what potential difference must it be accelerated, starting from rest, to acquire a speed of 10 m/s? [IPMT 2004] (1) 50 kv (2) 5 V (3) 50 V (4) 5 kv Page - 28

29 CUENT ELECTICITY 142. battery is charged at a potential of 15V for 8 hours when the current flowing is 10. The battery on discharge supplies a current of 5 for 15 hours. The mean terminal voltage during discharge is 14 V. The "Watt hour" efficiency of the battery is : [IPMT 2004] (1) 80% (2) 90% (3) 87.5% (4) 82.5% 143. Five equal resistances each of resistance are connected as shown in the Figure. battery of V volts is connected between and. The current flowing in FCE will be : [IPMT 2004] (1) V C (2) V 2 (3) 2V (4) 3V 144. galvanometer of 50 ohm resistance has 25 divisions. current of ampere gives a deflection of one D division. To convert this galvanometer into a voltmeter having a range of 25 volts, it should be connected with a resistance of : F (1) 245 in parallel (2) 2550 in series (3) 2450 in series (4) 2500 in parallel E [IPMT 2004] volt battery is connected to the terminals of a three metre long wire of uniform thickness and resistance of 100 ohm. The difference of potential between two points on the wire separated by a distance of 50 cm will be : (1) 3 volt (2) 1 volt (3) 1.5 volt (4) 2 volt [IPMT 2004] 146. esistance of an ideal voltmeter is : [PMT 2004] (1) zero (2) less than 1 ohm (3) more than 1 ohm (4) infinite 147. Potentiometer is used for measuring : [PMT 2004] (1) potential difference (2) current (3) internal resistance (4) none of these 148. Find potential of J with : respect to G (1) 40 V (2) 60 V (3) 20 V (4) 30 V 60V 0V 6 32 J G [PMT 2004] Page - 29

30 CUENT ELECTICITY 149. Eels are able to generate current with biological cells called electroplaques. The electroplaques in an Eel are arranged in 100 rows,each row stretching horizontally along the body of the fish containing 5000 electroplaques. The arrangement is suggestively shown below. Each electroplaques has an emf of 0.15 V and internal resistance of The water surrounding the Eel completes a circuit between the head and its tail. If the water surrounding it has a resistance of 500, the current an Eel can produce in water is about : [IIMS 2004] 0.15V rows 5000 electroplaques per row 500 (1) 1.5 (2) 3.0 (3) 15 (4) Two batteries, one of emf 18 volts and internal resistance 2 and the other of emf 12 volt and internal resistance 1, are connected as shown. The voltmeter V will record a reading of : (1) 18 volt (2) 30 vol (3) 14 volt (4) 15 volt 2 1 V 18V 12V [IPMT 2005] 151. When a wire of uniform cross-section a, length and resistance is bent into a complete circle, resistance between any two of diametrically opposite points will be : [IPMT 2005] (1) 2 (2) 4 (3) For the network shown in the figure the value of the current i is : (4) 4 [IPMT 2005] (1) 18 V 5 (2) 5 V 9 (3) 9 V 35 i 6 V 2 3 (4) 5 V 18 Page - 30

31 CUENT ELECTICITY 153. In potentiometer experiment when terminals of the cell is at distance of 52cm, then no current flows through it. When 5 shunt resistance is connected in it then balance length is at 40 cm. The internal resistance of the cell is : [PMT 2005] (1) 5 (2) (3) 52 8 (4) potentiometer wire has resistance 40 and its length is 10m. It is connected by a resistance of 760 in series. If emf of battery is 2V then potential gradient is : [PMT 2005] (1) V/m (2) V/m (3) V/m (4) V/m 155. In the circuit shown, if a conducting wire is connected between points and, the current in this wire will : [IPMT 2006] (1) flow from to (2) flow in the direction which will be decidedby the value of V (3) be zero (4) flow from to 1 V 156. The resistance of an ammeter is 13 and its scale is graduated for a current upto 100 amps. fter and additional shunt has been connected to this ammeter it becomes possible to measure currents upto 750 amperes by this meter. The value of shunt-resistance is : 3 [IPMT 2007] (1) 2 k (2) 20 (3) 2 (4) wire of resistance 12 ohms per meter is bent to form a complete circle of radius 10 cm. The resistance between its two diametrically opposite points, and as shown in the figure, is : [IPMT 2009] (1) 6 (2) 0.6 (3) 3 (4) See the electrical circuit shown in this figure. Which of the following equations is a correct equation for it? (1) 1 (i 1 + i 2 ) + i 1 r 1 = 0 [IPMT 2009] (2) 1 (i 1 + i 2 ) i 1 r 1 = 0 (3) 2 i 2 r 2 1 i 1 r 1 = 0 (4) 2 (i 1 + i 2 ) + i 2 r 2 = 0 i 1? 1 r 1 i 2 r 2? 2 Page - 31

32 CUENT ELECTICITY 159. galvanometer having a coil resistance of 60 shows full scale deflection when a current of 1.0 amp passes through it. It can be converted into an ammeter to read currents upto 5.0 amp by :- [IPMT 2009] (1) putting in parallel a resistance of 15 (2) putting in parallel a resistance of 240 (3) putting in series a resistance of 15 (4) putting in series a resistance of student measures the terminal potential difference (V) of a cell (of emf and internal resistance r) as a function of the current (I) flowing through it. The slope, and intercept, of the graph between V and I, then respectively, equal :- (1) and r (2) and r (3) r and (4) r and [IPMT 2009] 161. Two resistance has cofficient of temprature expentions are 1 & 2. If both are connected in series and parallel than temprature cofficient of resistance of combination will be (1) 1 1 2, (2), 1 2 (3) , 1 2 [IPMT-2010] 1 2 (4) None 162. The resistance of the four arms P, Q, and S in a Wheatstone s bridge are 10 ohm, 30 ohm, 30 ohm and 90 ohm, respectively. The emf and internal resistance of the cell are 7 volt and 0.5 ohm respectively. If the galvanometer resistance is 50 ohm, the current drawn from the cell will be : [NEET-2013] (1) 0.1 (2) 2.0 (3) 1.0 (4) wire of resistance 4 ohm is stretched to twice its original length. The resistance of stretched wire would be (1) 8 (2) 16 (3) 2 (4) 4 [NEET-2013] 164., and C are voltmeters of resistance, 1.5 and 3 respectively as shown in the figure. When some potential difference is applied between and Y, the voltmeter readings are V, V and V C respectively. Then C [IPMT-2015] (1) V = V V C (2) V V V C (3) V = V = V C (4) V V = V C 165. cross a metallic conductor of non-uniform cross section a constant potential difference is applied. The quantity which remains constant along the conductor is : [IPMT-2015] (1) Drift velocity (2) Electric field (3) Current density (4) Current 166. potentiometer wire has length 4 m and resistance 8. The resistance that must be connected in series with the wire and an accumulator of e.m.f. 2V, so as to get a potential gradient 1 mv per cm on the wire is: (1) 44 (2) 48 (3) 32 (4) 40 Y [IPMT-2015] Page - 32