Question

The magnetic potential energy stored in a certain inductor is $25\text{mJ}$, When the current in the inductor is $60\text{mA}$ This inductor is of inductance-

• A. $0.138\text{H}$
• B. $138.88\text{H}$
• C. $1.389\text{H}$
• D. $13.89\text{H}$

Answer 1

The correct option is D $13.89\text{H}$

Energy stored in the inductor is,

$E=\frac{1}{2}L{i}^2$

$25\times {10}^{-3}$ = $\frac{1}{2}L\times (60\times {10}^{-3}{)}^2$

$L=\frac{50\times {10}^{-3}}{36\times {10}^{-4}}$ = $\frac{500}{36}$

$\therefore L=13.89\text{H}$

<!--td {border: 1px solid #ccc;}br {mso-data-placement:same-cell;}--> Hence, $\left(B\right)$ is the correct answer.