If a current change of 6 A in one coil causes the flux in the second coil of 2000 turns to change by \( 12 \times 10^{-4}\,\mathrm{Wb} \) per turn, the mutual inductance of the pair of coils would be
Answer & explanation
Correct answer: option 2
The correct answer is Option (2) → 0.4 H
The mutual inductance is the total flux linked with the second coil per unit current change in the first, \( N_{2}\Phi_{2} = M I_{1} \).
\( \displaystyle M = \frac{N_{2}\,\Delta\Phi_{2}}{\Delta I_{1}} = \frac{2000\times12\times10^{-4}}{6} = \frac{2.4}{6} = 0.4\,\mathrm{H} \)