Electromagnetic Induction - Result Question 21
21. 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
(a) $0.138 H$
(b) $138.88 H$
(c) $13.89 H$
(d) $1.389 H$
[2018]
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Answer:
Correct Answer: 21. (c)
Solution:
- (c) From question energy stored in inductor, $U=25 \times 10^{-3} J$
Current, $I=60 mA$
Energy stored in inductor $U=\frac{1}{2} L I^{2}$
$25 \times 10^{-3}=\frac{1}{2} \times L \times(60 \times 10^{-3})^{2}$
$L=\frac{25 \times 2 \times 10^{6} \times 10^{-3}}{3600}=13.89 Hm$
