### NEET Solved Paper 2018 Question 21

##### Question: The magnetic potential energy stored in a certain inductor is 25 mJ, when the current in the inductor is 60 mA. This inductor is of inductance [NEET - 2018]

#### Options:

A) 1.389 H

B) 138.88 H

C) 0.138 H

D) 13.89 H

## Show Answer

#### Answer:

Correct Answer: D

#### Solution:

Energy stored in inductor $ \text{U=}\frac{1}{2}L{l^{2}} $ $ 25\times 1{0^{-3}}=\frac{1}{2}\times L\times {{(60\times {10^{-3}})}^{2}} $

$ \text{L=}\frac{\text{25 }\times\text{ 2 }\times\text{ 1}{0^{6}}\times\text{ 1}{0^{\text{-3}}}}{3600} $ $ \text{=}\frac{500}{36} $

$ \text{= 13}\text{.89 H} $