Question

The flux linked with a coil is $0.8Wb$ when a $2A$ current is flowing through it. If this current begins to increase at the rate of $400A/s$, the induced emf in the coil will be

• A. $20V$
• B. $40V$
• C. $80V$
• D. $160V$

Answer 1

The correct option is D $160V$

$\varphi =Li$
$0.8=L\times 2$
$L=\frac{0.8}{2}=0.4$
$emf=L\frac{di}{dt}$
$=0.4\times 400$
$=160V$