Any change in the magnetic field associated with a coil of wire will cause an emf to be induced in the coil. This emf is called induced emf and if the conductor circuit is closed, current will also circulate through the circuit. This current is called induced current. The magnetic field can be changed by following methods:
By moving a magnet towards or away from the coil
By moving the coil into or out of the magnetic field.
By changing the area of a coil placed in the magnetic field