Question

Find the time taken for the current in an inductor to change to 2A from 0A if the power in the inductor is 5W. The value of inductance is 10H.

(a) 1s

(b) 2s

(c) 3s

(d) 4s

I have been asked this question in an interview for internship.

The doubt is from Energy Stored in an Inductor topic in division Inductance in a DC Circuit of Basic Electrical Engineering

Answer 1

Correct choice is (d) 4s

The explanation is: The expression for power in an inductive circuit is:

P = LI^2/2t

Substituting the values from the given question, we get t=4s.