Question

The magnitude of the induced emf in a coil of inductance $30mH$ in which the current changes from $6A$ to $2A$ in $2s$ is

• A. 0.06 V
• B. 0.6 V
• C. 1.06 V
• D. 6 V

Answer 1

Answer: (A)

The magnitude of induced emf,
$|e|=-L\frac{di}{dt}\Rightarrow e=-30\times 10^{-3}\times \left(\frac{6-2}{2}\right)$
$=-30\times 10^{-3}\times \frac{4}{2}=-0.06V$