Question

An inductor (L = 100mH), a resistor (R = 100Ω) and a battery (E = 100V) are initially connected in series as shown in the figure. After a long time the battery is disconnected after short circuiting the points A and B. The current in the circuit 1ms after the short circuit is

(a) 1A 

(b) (1/e)A

(c) eA 

(d) 0.1A.

Answer 1

Correct Option(b) (1/e)A

Explanation:

This is a combined example of growth and decay of current in an L-B circuit

[as inductor would be shorted in the steady state]

After this decay of current starts in the circuit, according to the equation,