Features of waves – WJECThe electromagnetic spectrum

The electromagnetic spectrum is a group of seven types of wave that are made up from electric and magnetic fields. The properties of the waves in the spectrum depend on their wavelength and frequency. Higher frequencies transmit higher energies.

Although the wavelength and frequency of these waves are all different, all regions of the electromagnetic spectrum transfer energy. Another thing that they have in common is that they all travel at the same speed through a vacuum (space), which is the speed of light or about 300,000,000 m/s (metres per second) also 3 × 10⁸ ms^-1.

You will need to learn the order of the spectrum for the exam. You also need to know what the different waves are used for.

The term radiation can be used for both electromagnetic waves and for energy given out by radioactive materials. Short wavelength parts of the electromagnetic spectrum (ultraviolet, X-ray and gamma ray) are able to interact with atoms and to damage cells by the energy that they carry. This type of radiation is known as ionising radiation.