(N/A) The figure shows a bar magnet and a helical coil of wire connected to a galvanometer.
When there is no relative motion between the bar magnet and the coil,as shown in part $(a)$,the galvanometer shows zero deflection,indicating no current is flowing.
However,when the magnet moves toward the coil,as in part $(b)$,an induced current is generated in the coil.
As the magnet approaches,the magnetic field lines passing through the coil increase,and this change in magnetic flux induces the current.
When the magnet moves away from the coil,a current is also induced,but its direction is reversed because the magnetic flux through the coil decreases.
Thus,it is the change in the magnetic field (or magnetic flux) linked with the coil that generates the induced current.