Mutual Inductance question from JEE Main 2013 (9 Apr, Shift 1)

Answer: (b)

1. $V = -M\dfrac{dI}{dt}$, so the slope of $I(t)$ is opposite in sign to $V$ and proportional to it.
2. First part: $V > 0$, starting and ending at zero, so $I$ falls with zero slope at both ends (a smooth cosine-like fall).
3. Second part: $V$ is a negative constant, so $I$ rises linearly.
4. After that $V = 0$, so $I$ stays constant. Only graph C has this shape.
5. So the answer is (b) C.