Question

A current of $2A$ is increasing at the rate of $4A/s$ through a coil of inductance $2H$. The energy stored in the inductor per unit time is

• A. $2W$
• B. $1W$
• C. $16W$
• D. $4W$

Answer 1

Answer: (C)

$16W$

Energy stored per unit time is
$=\frac{dU}{dt}$
$=\frac{d}{dt}\left(\frac{1}{2}L{i}^2\right)$
$=Li\frac{di}{dt}$
$=2\times 2\times 4$
$=16W$