Explanation

This question is based on electromagnetic induction and Lenz’s law, a very important concept for JEE Main, JEE Advanced and IIT JEE.

The direction of induced current depends on whether the net magnetic flux through coil $C_2$ is increasing or decreasing.

Coil $C_1$ carries current in anti-clockwise direction, so it produces magnetic field along the axis in one direction.

Coil $C_3$ carries current in clockwise direction, so it produces magnetic field along the axis in the opposite direction.

Since $C_2$ is exactly midway, the flux through $C_2$ depends on the relative motion of $C_1$ and $C_3$.

If $C_1$ moves towards $C_2$, the magnetic flux due to $C_1$ through $C_2$ increases.

If $C_3$ moves away from $C_2$, the magnetic flux due to $C_3$ through $C_2$ decreases.

Both these changes cause a net increase in magnetic flux through $C_2$ in the direction of the field produced by $C_1$.

According to Lenz’s law, the induced current in $C_2$ will flow in such a direction that it opposes the increase in flux.

To oppose this increase, $C_2$ must produce a magnetic field in the opposite direction, which corresponds to a clockwise current.

Hence, the induced current in $C_2$ is clockwise when:

$C_1$ moves towards $C_2$ and $C_3$ moves away from $C_2$.

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