Electromagnetic induction is the production of voltage in a conductor when there is relative motion between the conductor and the magnetic field.
When a solenoid is connected to a galvanometer as shown
If the North pole of a strong magnet is moved towards the coil, the galvanometer deflects for a short time to the right. The deflection shows that there is induced current or voltage in the coil.
If the South pole of the magnet is moved towards the coil, the galvanometer deflects to the left. When the magnet is stationary in the solenoid, no deflection takes place.