A magnet NS is suspended from a spring and while oscillates, the magnet moves in and out of the coil C. The coil is connected to a galvanometer G. Then as the magnet oscillates 

Given data:

Magnet NS from a spring

Oscillate coil =c

Concepts used: magnetic field

Explanation:

As the magnet approaches the coil, the magnetic flux through the coil changes and current is induced in one direction.

When the magnet moves away from the coil, the magnetic flux through the coil also changes, inducing a current in the opposite direction.

So G indicates left and right deflection.

Eddy current losses also reduce the amplitude of the SHM of the magnets, which also reduces the maximum velocity. Therefore, the deflection amplitude of G is also reduced.