Self-inductance: At what rate would the current in a 100-mH inductor have to change to induce an emf of 1000 V in the inductor?
A) 100 A/s
B) 1 A/s
C) 1000 A/s
D) 10,000 A/s
E) 10 A/s

Question

Quizplus · Accepted Answer

The formula for emf induced in an inductor is given by 
emf = - L(dI/dt)
where L is the inductance, I is the current and (dI/dt) is the rate of change of current. 
Rearranging the formula, we get 
(dI/dt) = - emf/L = -1000/0.1 = -10000 A/s
Since the question asks for the magnitude of the rate of change of current, we take the absolute value which is 10000 A/s. So the answer is D.

Self-Inductance: at What Rate Would the Current in a 100-MH