Radiation

Radiation (radiant energy): energy in the form of electromagnetic waves. Different forms of radiation comprise the electromagnetic spectrum and are characterised by their different wave frequency and wavelength. Radiation is emitted from matter in the form of photons .

The following types of radiation make up the electromagnetic spectrum (in order of decreasing energy and increasing wavelength): cosmic rays, gamma rays , x-rays , UV (ultraviolet) rays, visible light rays, infrared, microwave, radio (Hertzian) waves and electric waves. These electromagnetic waves have no mass and are not electrically charged. The shortest wavelength forms of radiation are most penetrating and are the most damaging to living tissue.

See Also

Radioactivity , Conduction and Convection .