Question

A series R-L circuit with R = 30Ω and L = 15H has a constant voltage V = 60V applied at t = 0 as shown in the figure. Determine the current (A) in the circuit at t = 0^+.

(a) 1

(b) 2

(c) 3

(d) 0

This question was posed to me by my college professor while I was bunking the class.

My query is from DC Response of an R-L Circuit in chapter Transients of Network Theory

Answer 1

Correct answer is (d) 0

For explanation: Since the inductor never allows sudden changes in currents. At t = 0^+ that just after the initial state the current in the circuit is zero.