Electromagnetic Induction - Result Question 29

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29. A varying current in a coil changes from 10A to zero in $0.5 sec$. If the average e.m.f induced in the coil is $220 V$, the self-inductance of the coil is

======= ####29. A varying current in a coil changes from 10A to zero in $0.5 sec$. If the average e.m.f induced in the coil is $220 V$, the self-inductance of the coil is

3e0f7ab6f6a50373c3f2dbda6ca2533482a77bed:content/english/neet-pyq-chapterwise/physics/electromagnetic-induction/electromagnetic-induction—result-question-29.md (a) $5 H$

(b) $6 H$

(c) $11 H$

(d) $12 H$

[1995]

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Answer:

Correct Answer: 29. (c)

Solution:

  1. (c) Initial current $(I_1)=10 A$; Final current $(I_2)$ $=0$; Time $(t)=0.5 sec$ and induced e.m.f. $(\varepsilon)=$ $220 V$.

Induced e.m.f. ( $(\varepsilon)$

$=-L \frac{d I}{d t}=-L \frac{(I_2-I_1)}{t}=-L \frac{(0-10)}{0.5}=20 L$

or, $L=\frac{220}{20}=11 H$

[where $L=$ Self inductance of coil]