Transfer of Energy by EM Waves (AQA GCSE Physics): Revision Notes

Electromagnetic waves are transverse waves. They transfer energy from the source of the waves to an absorber.

For example, infrared waves are emitted from the sun. The sun is a source of electromagnetic radiation. The infrared waves travel to the Earth and heat up the air. The air is the absorber.

Key Points Electromagnetic waves are transferred by vibrations of electric and magnetic fields. This means they do not require a medium to travel through. Hence, electromagnetic waves can travel through a vacuum such as space.

There are lots of types of electromagnetic waves that form a continuous spectrum of electromagnetic radiation. Different types of electromagnetic waves have different frequencies, wavelengths and properties. But all electromagnetic waves travel at the same speed – the speed of light. The full spectrum of electromagnetic waves is shown below.

Humans can only see a very small portion of the electromagnetic spectrum. The waves in this portion are called visible light.