Q. No.Current in a circuit falls from \(5.0\) A to \(0\) A in \(0.1\) s. If an average emf of \(200\) V is induced, the self-inductance of the circuit is:
1. \(4\) H
2. \(2\) H
3. \(1\) H
4. \(3\) H
The back emf induced in a coil, when current changes from 1 ampere to zero in one milli-second, is 4 volts. The self-inductance of the coil is:
1.
2.
3.
4.
The current through a choke coil increases from zero to 6 A in 0.3 seconds and an induced emf of 30 V is produced. The inductance of the coil is:
| 1. | 5 H | 2. | 2.5 H |
| 3. | 1.5 H | 4. | 2 H |
A long solenoid has 1000 turns. When a current of 4 A flows through it, the magnetic flux linked with each turn of the solenoid is 4 x 10-3 Wb. The self-inductance of the solenoid is:
1. 3 H
2. 2 H
3. 1 H
4. 4 H
A coil of resistance 20 and inductance 5 H has been connected to a 200 V battery. The maximum energy stored in the coil is:
| 1. | 250 J | 2. | 125 J |
| 3. | 500 J | 4. | 100 J |
Given below are two statements: one is labelled as Assertion (A) and the other is labelled as Reason (R):
| Assertion (A): | Self-inductance is called the inertia of electricity. |
| Reason (R): | It is on account of self-inductance that the coil opposes any change in current passing through it. |
In the light of the above statements choose the correct answer from the options given below:
| 1. | Both (A) and (R) are true and (R) is the correct explanation of (A). |
| 2. | Both (A) and (R) are true but (R) is not the correct explanation of (A). |
| 3. | (A) is true but (R) is false. |
| 4. | Both (A) and (R) are false. |
The current I in an inductance coil varies with time t according to the graph shown in the figure. Which one of the following plots shows the variation of voltage in the coil with time?
| 1. |  |
2. |  |
| 3. |  |
4. |  |
The number of turns in a coil of wire of fixed radius & length is 600 and its self-inductance is 108 mH. The self-inductance of a coil of 500 turns will be:
1. 74 mH
2. 75 mH
3. 76 mH
4. 77 mH
A 10 H inductor carries a current of 20 A. How much ice at 0°C could be melted by the energy stored in the magnetic field of the inductor?
Latent heat of ice is 2.26 × J/kg.
| 1. | 0.08 kg | 2. | 8.8 kg |
| 3. | 0.88 kg | 4. | 0.44 kg |
A coil is wound of a frame of rectangular cross-section. If the linear dimensions of the frame are doubled and the number of turns per unit length of the coil remains the same, then the self inductance increases by a factor of:
| 1. | 6 | 2. | 12 |
| 3. | 8 | 4. | 16 |
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