Electromagnetic Induction

Notes

Electromagnetic Induction

1. Electromagnetic Induction

When there is relative motion between a coil and a magnet, current is induced in the coil. This current is known as induced current.

The phenomenon of production of electric current is known as electromagnetic induction.

2. Faraday's Experiments

First Experiment

In this experiment, one coil containing one galvanometer and a bar magnet are used.

Step 1: A bar magnet is brought closer to the coil. Hence, magnetic flux is linked with the coil. Due to this, the galvanometer shows deflection in a particular direction.

Step 2: Now, the magnet is moved away from the coil. Hence, magnetic flux is linked with the coil, and due to this the galvanometer shows deflection in the direction opposite to the direction of previous deflection.

Step 3: When the bar magnet is stationary, there is no deflection in the galvanometer because there is no change in magnetic flux linked with the coil.

Conclusion

The current is induced in the coil only if there is a change in the magnetic flux.

Second Experiment

In this experiment, one coil containing one galvanometer and another coil which is in the shape of a solenoid and connected to a source of current with a switch are used.

Step 1: One coil is brought closer to the other coil. Hence, magnetic flux is linked with the coil. Due to this, the galvanometer shows deflection in a particular direction.

Step 2: Now, the coil is moved away from the other coil. Hence, magnetic flux is linked with the coil. Due to this, the galvanometer shows deflection in the direction opposite to the direction of previous deflection.

Step 3: When the coil is stationary, there is no deflection in the galvanometer because there is no change in magnetic flux linked with the coil.

Conclusion

The current is induced in the coil only if there is a change in magnetic flux.

Third Experiment

In this experiment, one coil containing one galvanometer and another coil which is also in the shape of a solenoid connected to a source of current with a switch are used.