Current Electricity PYQs Set 2 (PDF)

Set 2 of 25 · Questions 31-60 of 723

In the print window choose “Save as PDF”. The file prints without a web address or date line.

Mere Teacher · Previous Year Questions JEE Main Physics · Current Electricity · Set 2 (Q31-60)
Scan or visit mereteacher.com for free PYQ practice, timed CBT tests, step-by-step solutions and BroBot AI. Answers and solutions are free with a sign-up.
31. $Given below are two statements: Statement-I: The equivalent emf of two nonideal batteries connected in parallel is smaller than either of the two emfs. Statement-II: The equivalent internal resistance of two nonideal batteries connected in parallel is smaller than the internal resistance of either of the two batteries. choose the correct answer from the options given below.$ (1) $Both Statement-I and Statement-II are false$ (2) $Statement-I is false but Statement-II is true$ (3) $Both Statement-I and Statement-II are true$ (4) $Statement-I is true but Statement-II is false$ 32. $When a current of 5mA is passed through a galvanometer having a coil of resistance 15Ω, it shows full scale defection. The value of the resistance to be put in series with the galvanometer to convert it into a voltmeter of range 0 - 10 V is:$ (1) $4.005 \times 1 0^{3}$ (2) $1.985 \times 1 0^{3}$ (3) $2.045 \times 1 0^{3}$ (4) $2.535 \times 1 0^{3}$ 33. $Balancing point of a potentiometer shifts from a length of 60 cm to 40 cm by shunting the cell with a 4 ohm resistance. What is the internal resistance of the cell?$ (1) $1Ω$ (2) $2Ω$ (3) $4Ω$ (4) $6Ω$ 34. $Three resistances 2Ω, 3Ω and 4Ω are connected in parallel. The ratio of currents passing through them when a potential difference is applied across its ends will be$ (1) $6 : 4 : 3$ (2) $4 : 3 : 2$ (3) $6 : 3 : 2$ (4) $5 : 4 : 3$ 35. $As the temperature increases, the electrical resistance [NEET 2022]$ (1) $decreases for both conductors and semiconductors.$ (2) $increases for conductors but decreases for semiconductors.$ (3) $decreases for conductors but increases for semiconductors.$ (4) $increases for both conductors and semiconductors.$ 36. $A copper wire is stretched to make it 0.5 % longer. The percentage change in its electrical resistance if its volume remains unchanged is:$ (1) $2.0 %$ (2) $2.5 %$ (3) $1.0 %$ (4) $0.5 %$ 37. $A motor operating on 100 V draws a current of 1 A. If the efficiency of the motor is 91.6 %, then the loss of power in units of cal / s is$ (1) $6.2$ (2) $2$ (3) $8.4$ (4) $4$ 38. $A thermocouple of negligible resistance produces an e.m.f. of 40 µV/°C in the linear range of temperature. A galvanometer of resistance 10 ohm whose sensitivity is 1µA/div, is employed with the thermocouple. The smallest value of temperature difference that can be detected by the system will be:$ (1) $0.5°C$ (2) $1°C$ (3) $0.1°C$ (4) $0.25°C$ 39. $A milli voltmeter of 25 milli volt range is to be converted into an ammeter of 25 ampere range. The value (in ohm) of necessary shunt will be:$ (1) $0.001$ (2) $0.01$ (3) $1$ (4) $0.05$ 40. $Two metal wires of same length, same area of cross section have conductivities of their material σ_{1} and σ_{2} . If they are connected in series, the effective conductivity is$ (1) $\frac{σ _{1} σ _{2}}{σ _{1} + σ _{2}}$ (2) $\frac{2 σ _{1} σ _{2}}{σ _{1} + σ _{2}}$ (3) $\frac{σ _{1} σ _{2}}{σ _{1} - σ _{2}}$ (4) $\frac{2 σ _{1} σ _{2}}{σ _{1} - σ _{2}}$ 41. $A moving coil galvanometer of resistance 100Ω shows a full scale deflection for a current of 1 mA. The value of resistance required to convert this galvanometer into an ammeter, showing full scale deflection for a current of 5 mA, is____Ω$ (1) $0.5$ (2) $2.5$ (3) $10$ (4) $25$ 42. $Two bulbs rated 25 W 220 V and 100 W 220 V are connected in series to a 440 V supply. Then,$ (1) $100 W bulb fuses$ (2) $25 W bulb fuses$ (3) $both the bulbs fuse$ (4) $neither of the bulb fuses.$ 43. $If the masses of three wires of same material are in the ratio of 1 : 2 : 3 and their lengths are in the ratio of 3:2:1, then electrical resistances of these wires are in the ratio$ (1) $1 : 1 : 1$ (2) $1 : 2 : 3$ (3) $9 : 4 : 1$ (4) $27 : 6 : 1$ 44. $Given below are two statements: Statement I: The equivalent resistance of resistors in a series combination is smaller than least resistance used in the combination. Statement II: The resistivity of the material is independent of temperature. In the light of the above statements, choose the correct answer from the options given below:$ (1) $Both Statement I and Statement II are false$ (2) $Both Statement I and Statement II are true$ (3) $Statement I is true but Statement II is false$ (4) $Statement I is false but Statement II is true$ 45. $A galvanometer has a coil of resistance 200Ω with a full-scale deflection at 20 μA . The value of resistance to be added to use it as an ammeter of range (0 - 20) mA is;$ (1) $0.40Ω$ (2) $0.20Ω$ (3) $0.50Ω$ (4) $0.10Ω$ 46. $A potentiometer is an accurate and versatile device to make electrical measurements of EMF because the method involves$ (1) $potential gradients$ (2) $a condition of no current flow through the galvanometer$ (3) $a combination of cells, galvanometer and resistances$ (4) $cells$ 47. $In a region of uniform electric field of intensity E, an electron of mass m_{e} is released from rest. The distance travelled by the electron in a time t is$ (1) $\frac{2 m _{e} t ^{2}}{e}$ (2) $\frac{eE t ^{2}}{2 m _{e}}$ (3) $\frac{m _{e} g t ^{2}}{eE}$ (4) $\frac{2 E t ^{2}}{e m _{e}}$ 48. $A galvanometer of resistance 20Ω gives a deflection of 5 divisions when 1 mA current flows through it. The galvanometer scale has 50 divisions. To convert the galvanometer into a voltmeter of range 25 volt, we should connect a resistance of$ (1) $1240Ω in series$ (2) $2480Ω in series$ (3) $2180Ω in parallel$ (4) $20Ω in parallel.$ 49. $A galvanometer having a coil resistance of 100 Ω gives a full scale deflection, when a current of 1 mA is passed through it. The value of the resistance, which can convert this galvanometer into ammeter giving a full scale deflection for a current of 10 A, is:$ (1) $2$ (2) $0.1$ (3) $3$ (4) $0.01$ 50. $A galvanometer having a resistance of 20Ω and 30 divisionon both sides has figure of merit 0.005 ampere/division. Theresistance that should be connected in series such that itcan be used as a voltmeter upto 15 volt, is:$ (1) $100Ω$ (2) $120Ω$ (3) $80Ω$ (4) $125Ω$ 51. $Specific resistance of a conductor increases with$ (1) $increase in temperature$ (2) $increase in cross‐section area$ (3) $increase in cross‐section and decrease in length$ (4) $decrease in cross‐section area.$ 52. $The difference of temperature in a material can convert heat energy into electrical energy.To harvest the heat energy, the material should have$ (1) $high thermal conductivity and high electrical conductivity$ (2) $low thermal conductivity and low electrical conductivity$ (3) $high thermal conductivity and low electrical conductivity$ (4) $low thermal conductivity and high electrical conductivity$ 53. $The velocity of charge carriers of current (about 1 ampere) in a metal under normal conditions is of the order of$ (1) $a fraction of mm/sec$ (2) $velocity of light$ (3) $several thousand meters/second$ (4) $a few hundred meters per second$ 54. $The deflection in galvanometer falls to (\frac{1}{4})^{th} when it is shunted by 3Ω . If additional shunt of 2Ω is connected to earlier shunt, the deflection in galvanometer falls to$ (1) $\frac{1}{2}$ (2) $(\frac{1}{3})^{rd}$ (3) $(\frac{1}{4})^{th}$ (4) $(\frac{1}{8.5})^{th}$ 55. $The effective resistance of a parallel connection that consists of four wires of equal length, equal area of cross-section and same material is 0.25Ω . What will be the effective resistance, if they are connected in series? [NEET 2021]$ (1) $0.25Ω$ (2) $0.5Ω$ (3) $1Ω$ (4) $4Ω$ 56. $Three copper wires of lengths and cross‐ sectional areas are (l, A), (2 l, A /2) and (l /2, 2 A) . Resistance is minimum in$ (1) $wire of cross‐sectional area 2 A$ (2) $wire of cross‐sectional area \frac{A}{2}$ (3) $wire of cross‐sectional area A$ (4) $same in all three cases.$ 57. $When a resistance of 5 Ω is shunted with a moving coil galvanometer, it shows a full scale deflection for a current of 250 mA, however when 1050 Ω resistance is connected with it in series, it gives full scale deflection for 25 volt. The resistance of galvanometer is________Ω .$ 58. $The current flowing through a conductor connected across a source is 2 A and 1. 2 A at 0°C and 100°C respectively. The current flowing through the conductor at 50°C will be_____x 1 0^{2} mA.$ 59. $First, a set of equal resistors of 10Ω each are connected in series to a battery of emf 20V and internal resistance 10Ω . A current I is observed to flow. Then, the resistors are connected in parallel to the same battery. It is observed that the current is increased 20 times, then the value of n is .$ 60. $A current of 2 A flows through a wire of cross-sectional area 25.0 m m^{2} . The number of free electrons in a cubic meter are 2. 0 x 1 0^{28} . The drift velocity of the electrons is _____x 1 0^{- 6} m s^{- 1} (given, charge on electron = 1.6 x 1 0^{- 19} C).$