Question

Two coaxial coils are very close to each other and their mutual inductance is $5mH$. If a current $50\sin 500t$ is passed in one of the coils then the peak value of induced e.m.f. in the secondary coil will be

• A. 5000 V
• B. 500 V
• C. 150 V
• D. 125 V

Answer 1

Answer: (D)

$\varphi =Mi$
$\frac{d\varphi }{dt}=\frac{Mdi}{dt}$
$\epsilon =5\times 10^{-3}(50)(500)\cos \omega t$
${\epsilon }_{\max }=125V$