rayonnement électromagnétique

CONT: La gamme des longueurs d'onde des rayonnements électromagnétiques est très étendue depuis les rayons cosmiques jusqu'aux ondes hertziennes en passant par les rayons gamma, les rayons X, la lumière ultraviolette, le visible et l'infrarouge.
OBS: Les deux mots «radiation» et «rayonnement» ne représentent pas des notions complètement distinctes; le premier est employé de préférence lorsque l'on considère essentiellement l'aspect corpusculaire, le second désignant surtout l'aspect ondulatoire électromagnétique.

CONT: The word radiation is commonly used in several distinct although related senses. First, it is a term for the process by which energy is transferred and is able to exert an effect at a distance without the need for any physical connection between source and receiver. In this broad sense, radiation includes energy transfer both by electromagnetic waves (as in the case of gamma rays, ultra-violet rays or radio waves) and by energetic particles (such as alpha or beta particles emitted from nuclei in the process of radioactive decay). The more precise terms ""electromagnetic radiation"" and ""particulate radiation"" differentiate between these two phenomena.
CONT: Electromagnetic radiation differs from other forms, such as alpha radiation, beta radiation and neutron radiation in that photons have zero charge and zero mass.