A current of 15A in the primary coil of a circuit is reduced to zero at a uniform rate in $10^{-6}s$. If the coefficient of the Mutual Inductance is 4 H, what is the Induced emf in the secondary coil?

$6×10^7 V$

The correct answer is Option (3) → $6×10^7 V$

The induced electromagnetic force (emf) of the secondary coil is,

$ε_2=-M\frac{dI_1}{dt}$

and,

$\frac{dI_1}{dt}=\frac{ΔI_1}{Δt}=\frac{15A}{10^{-6}s}=1.5×10^7A/s$

∴ Induced emf, $ε_2=-(4H)×(1.5×10^7A/s)$

$=-6×10^7 V$