Question

The current decays from 5A to 2A in 0.01s in a coil. The emf induced in a coil nearby it is 30V. Calculate the mutual inductance of the coils

• A. 0.1H
• B. 0.2H
• C. 0.5H
• D. 0.01H

Answer 1

The correct option is A 0.1H

$e=-\frac{d\varphi }{dt}=-M\frac{di}{dt}$
$30=-M\left[\frac{2-5}{0.01}\right]$
$30\times {10}^{-2}=3M$
$M=0.1H$