Electromagnetic Induction Ques 32

32. The current in self inductance $L=40 $ $mH$ is to be increased uniformly from $1 $ $amp$ to $11$ $ amp$ in $4 $ milliseconds. The e.m.f. induced in the inductor during the process is

[1990]

(a) $100$ volt

(b) $0.4$ volt

(c) $4.0$ volt

(d) $440$ volt

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Answer:

Correct Answer: 32.(a)

Solution:

  1. (a) $e=L \frac{d i}{d t}$

Given that $L=40 \times 10^{-3}$ $ H$,

$di=11 A-1 A=10 $ $A$

and $dt=4 \times 10^{-3} $ $s$

$\therefore e=40 \times 10^{-3} \times(\frac{10}{4 \times 10^{-3}})=100$ $ V$