A coil with a self-inductance of 6.0 H is connected to a dc battery through a switch. As soon as the switch is closed, the rate of change of current is 2.0 A/s. What is the emf induced in this coil at this
Instant?
A) 6.0 V
B) 0.0 V
C) 12 V
D) 3.0 V
E) 0.33 V

Question

Quizplus · Accepted Answer

The induced emf in a coil is given by the formula $ \varepsilon = -L \frac{dI}{dt} $, where $ L $ is the self-inductance and $ \frac{dI}{dt} $ is the rate of change of current. Substituting the given values, $ \varepsilon = -6.0 \, \text{H} \times 2.0 \, \text{A/s} = -12 \, \text{V} $. The negative sign indicates the direction of the induced emf, which is not required here, so the magnitude is 12 V.

A Coil with a Self-Inductance of 6