Energy radiated in the form of a Wave caused by an Electric Field interacting with a Magnetic Field. Electromagnetic Radiation is the result of the acceleration of a Charged particle. It does not require a material medium, and can travel through a Vacuum. The theory of electromagnetic radiation was developed by Maxwell, James Clerk and published in 1865, although his ideas were not accepted until Heinrich Hertz proved the existence of Radio waves in 1887. In order of decreasing Wavelength and increasing Frequency (see Electromagnetic Spectrum ), the various types of electromagnetic radiation are RADIO waves, Microwave(s) , INFRARED RADIATION, visible Light, ULTRAVIOLET RADIATION, X-Rays, and GAMMA RADIATION. The possible sources of electromagnetic radiation are
directly related to wavelength; long radio waves are produced by large Antennas such as those used by broadcasting stations; much shorter visible light
waves are produced by the Motions of charges within atoms; the shortest waves, those of gamma radiation,
result from changes within the nucleus of the atom. The individual quantum (see Quantum Theory) of electromagnetic radiation is known as the Photon(s).