Question

An average emf of $20V$ is induced in an inductor when the current in it is changed from $2.5A$ in one direction to the same value in the opposite direction in $0.1$ s. The self-inuctance of the inductor is

• A. $zero$
• B. $0.2H$
• C. $0.4H$
• D. $1H$

Answer 1

The correct option is C $0.4H$

Given that,

Average emf $V=20V$

Current $i=2.5A$

We know that,

$V=L\frac{dI}{dt}$

$20=L\times \frac{5}{0.1}$

$L=\frac{20}{50}$

$L=0.4Henry$

Hence, the self-inductance is $0.4henry$