## What is electromagnetic induction?

Generation of electricity in a conductor when a magnetic field is cutting with the conductor is known as electromagnetic induction.

• Some sources can generate electricity by rotating or else by moving them. e.g.: – bicycle dynamo, electric generators

## Let’s identify how electricity is generated in a dynamo.

### You will need –

A coiled copper wire, a bar magnet, and a galvanometer.

### Method –

• Connect both ends of the coil to the galvanometer.
• Then move one end of the bar magnet, into and out of the coil.
• Thereafter, observe the indicator of the galvanometer for its deflection / movement.

### Observations –

The indicator of the galvanometer is getting to deflecting.

## Conclusion –

The electric current was generated by, moving a magnet inside the wire coil. In dynamo, electricity is generated in the same manner.

The process of electricity generation in dynamo is electromagnetic induction.

The generation of electricity in a conductor, when the magnetic field is cutting with the conductor, is known as electromagnetic induction.

Now you have seen that an electric current could be generated by the moving magnet inside the coil of wire in the above activity.

In bicycle dynamo, generators, hydropower stations, and wind power stations, electricity is generated in the same manner as above

## How to make an efficient dynamo?

The efficiency of the dynamo can be increased by increasing the number of turns of the coil and the power of the magnet.

• Increase the number of turns of the coil and repeat the activity.
• Observe the amount of movement of the galvanometer indicator.

Observations –

The indicator of the galvanometer deflects more than the initial practical.

Do the activity again with a powerful magnet and note down the observations.

Observations –

The indicator of the galvanometer deflects more than the initial practical.

## Dynamos

Equipment that generates electricity can be grouped as given below,

according to the way they generate electricity.

1. Electric cells and batteries: – Equipment that generates electricity by

a chemical reaction.

2. Dynamo: – Equipment that generates electricity by rotating or moving.

3. Solar cell: – Equipment that generates electricity by using solar energy

## Bicycle Dynamo

There is a conducting coil and a permanent magnet in between in a bicycle dynamo.

The magnet in the dynamo rotates when the rear wheel of the bicycle rotates. There, electricity is generated in the conducting coil.

Thus, it will be clear to you, that electricity is generated in the bicycle dynamo, according to the principle of electromagnetic induction.