Potential Difference Across an Inductor

Practice Questions:

Question 1: moderate

The network shown in the figure is a part of a complete circuit. If at a certain instant the current i is 5 A and is decreasing at the rate of 10³A/s then \(V_{B}-V_{A}\) is :

1. 5 V

2. 10 V

3. 15 V

4. 20 V

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Question 2: easy

Assertion (A): When a circuit having large inductance is switched off sparking occurs at the switch.

Reason (R): Emf induced in an inductor is given by \( |\text{E}| = \text{L} |\frac{\text{di}}{\text{dt}}| \).

1. (1) Both (A) & (R) are true and the (R) is the correct explanation of the (A)

2. (2) Both (A) & (R) are true but the (R) is not the correct explanation of the (A)

3. (3) (A) is true but (R) is false

4. (4) Both (A) and (R) are false

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When a circuit with large inductance is switched off, \( \text{di/dt} \) is very large. This induces a large \( \text{EMF} = \text{L di/dt} \) across the inductor, causing sparking.

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