Electromagnetic (EM) waves are transverse waves. Their vibrations or oscillations are changes in electrical and magnetic fields at right angles to the direction of wave travel.
All electromagnetic waves:
- transfer energy as radiation from the source of the waves to an absorber
- can travel through a vacuum such as in space
- travel at the same speed through a vacuum or the air
Electromagnetic waves travel at 300,000,000 metres per second (m/s) through a vacuum.
Electromagnetic waves form a continuous spectrum of waves. This includes:
- waves with a very short wavelength, high frequency and high energy
- waves with a very long wavelength, low frequency and low energy
Electromagnetic waves can be separated into seven distinct groups in the spectrum.
Often a phrase is used to help remember the order of the groups of the electromagnetic spectrum such as Roman Men Invented Very Unusual X-ray Guns.
Each group contains a range of frequencies. For example, visible light contains the limited range of frequencies that can be detected by the human eye:
- red light has the lowest frequencies of visible light
- violet light has the highest frequencies of visible light