Physics - Understanding Electromagnetic induction (EMI) and electromagnetic force (EMF) - Physics

A circular copper coil is connected to a sensitive galvanometer, which initially shows zero reading, indicating no electricity source in the circuit.

When a bar magnet is moved swiftly towards the coil with its north pole facing it, the galvanometer deflects, showing that current is induced in the coil.

Moving the magnet away from the coil causes the galvanometer to deflect in the opposite direction, indicating current in the reverse direction. Repeating this with the south pole also reverses the deflections.

If the magnet is kept stationary, no deflection is observed. Similarly, moving the coil while the magnet is stationary also produces deflections, demonstrating that relative motion is key.

A relative motion between a magnet and a coil induces a current in the coil. This current is called an induced current and is produced by an induced electromotive force (EMF).

The phenomenon of producing an induced EMF in a closed circuit by the relative motion of a magnet and a coil is known as electromagnetic induction.