A pair of adjacent coils has a mutual inductance of 2.0 H. If the current in one coil changes from 0 to 30 A in 0.5 s, the change of the magnetic flux linked with the other coil would be
Answer & explanation
Correct answer: option 4
The correct answer is Option (4) → \( 60\,\mathrm{Wb} \)
By the definition of mutual inductance, the flux linked with the second coil is proportional to the current in the first coil.
\( \displaystyle \Phi_2 = M I_1 \;\Rightarrow\; \Delta\Phi_2 = M\,\Delta I_1 \)
\( M = 2.0\,\mathrm{H} \)
\( \Delta I_1 = 30 - 0 = 30\,\mathrm{A} \)
\( \displaystyle \Delta\Phi_2 = 2.0 \times 30 = 60\,\mathrm{Wb} \)
The time of 0.5 s is not needed for the change of flux; it is needed only for the induced emf.
Note: NTA picked this question from an NCERT (2026-27) exercise and changed the figures. Do not ignore NCERT while practising numericals.
NCERT (2026-27):
Exercises – …
