Current Electricity MCQ Questions and Answers for Practice

1. If a power of 100 watt is being supplied across a potential difference of 200 V, current flowing is

1. 4.1666666666666664E-2
2. 20 A
3. 2A
4. 0.5 A

2. A 5A fuse wire can with stand a maximum power of 1W in circuit. The resistance of the fuse wire is:

1. 0.4 Ω
2. 0.04 Ω
3. 0.2 Ω
4. 5 Ω

3. A carbon resistance is having a following coding green, orange, black, gold. The resistance of resistor is

1. 53 x 10⁰ ± 10%
2. 53 x 10 ± 10%
3. 53 x 10⁰ ± 5%
4. 53 x 10¹ ± 5%

4. A cell of emf E is connected with an external resistance R, then p.d. across cell is V. The internal resistance of cell will be

1. (V-E)R/V
2. (V-E)R/E
3. (E-V)R/E
4. (E-V)R/V

5. A steady current flows in a metallic conductor of non-uniform cross-section. The quantities/quantity constant along the length of the conductor is/are

1. Current and drift speed
2. Current only
3. Current, electric field and drift speed
4. Drift speed only

6. A uniform w ire connected across a supply produces heat H per second. If wire is cut into three equal parts and all the parts are connected in parallel across the same supply, the heat produced per second will be :

1. 3 H
2. H3
3. H/9
4. 9 H

7. A wire of resistance 3 Ω is cut into three pieces, which are then joined to form a triangle. The equivalent resistance between any corners of the triangle is :

1. 1/2 Ω
2. 1/3 Ω
3. 2/3 Ω
4. 3/2 Ω

8. An electric heater is connected to the voltage supply. After few seconds, current gets its steady value then its initial current will be

1. slightly less than its steady current
2. zero
3. equal to its steady current
4. slightly higher than its steady current

9. An electric heating element consumes 500 W, when connected to a 100 V line. If the line voltage becomes 150 V, the power consumed Will be:

1. 1000 W
2. 1125 W
3. 500 W
4. 750 W

10. At what temperature will the resistance of a copper wire become three times its value at 0⁰C? (Temperature coefficient of resistance for copper = 4 x 10^-3 per^oC)

1. 500^oC
2. 550^oC
3. 400^oC
4. 450^oC

11. By increasing the temperature, the specific resistance of a conductor and semiconductor

1. Increases, decreases
2. Decreases for both
3. Increases for both
4. Decreases for both

12. Calculate the amount of charge flowing in 2 minutes in a wire of resistance 10 ? when a potential difference of 20 V is applied between its ends

1. 20 C
2. 4C
3. 120 C
4. 240 C

13. For a metallic wire, the ratio V/i (V = the applied potential difference, i = current flowing) is

1. Decreases as the temperature rises
2. Increases or decreases as temperature rises, depending upon the metal
3. Independent of temperature
4. Increases as the temperature rises

14. If a certain piece of copper is to be shaped into a conductor of minimum resistance, its length (L) and cross-sectional area shall respectively be :

1. 2L, 2A
2. 2l, A/2
3. L, 2A
4. L/2, 2A

15. If n cells each of emf e and internal resistance r are connected in parallel, then the total emf and internal resistance will be

1. n ε, r/n
2. n ε, nr
3. ε, r/n
4. ε, nr