| a wave produced by the acceleration of an electric charge and propagated by the periodic variation of intensities of, usually, perpendicular electric and magnetic fields. |
Waves composed of undulating electrical fields and magnetic fields. The different kinds of electromagnetic waves, such as light and radio waves, form the electromagnetic spectrum. All electromagnetic waves have the same speed in a vacuum, a speed expressed by the letter c (the speed of light) and equal to about 186,000 miles (or 300,000 kilometers) per second.
