Question

When the current changes from $+2A$ to $-2A$ in $0.05second$, an e.m.f. of $8V$ is induced in a coil. The coefficient of self-induction of the coil is

• A. $0.2H$
• B. $0.4H$
• C. $0.8H$
• D. $0.1H$

Answer 1

The correct option is D $0.1H$

Induced EMF= $\Sigma =|-\frac{\delta \varphi }{\delta t}|=+\frac{\delta }{\delta t}\left(LI\right)+L\frac{\delta I}{\delta t}$

$\Rightarrow 8=L\left(\frac{2-(-2)}{0.05}\right)$

$\Rightarrow L=0.1H$ .