Electromagnetic induction is voltage induced by a change in a magnetic field.
Round a wire that has current flowing through it (solenoid) field lines act. The ends of each wire act as the poles.
If the direction of the current in reversed the poles will swap over.
The size of the induced voltage depends on. . .
Strength of magnet.
Area of coil.
Turns of the wire.
The four things spell SATS!
The magnet turns…