radio wave A very low frequency electromagnetic wave (from roughly 30 kilohertz to 100 gigahertz). Radio waves are used for the transmission of radio and television signals; the microwaves used in radar and microwave ovens are also radio waves. Many celestial objects, such as pulsars, emit radio waves. See more at electromagnetic spectrum. |
Waves at the end of the electromagnetic spectrum with the lowest frequency (less than 300 megahertz) and the longest wavelength (from a few feet to many miles). Because of their low frequency, radio waves carry very little energy compared to other electromagnetic waves. (See Planck's constant.)
Note: Radio waves can pass through the atmosphere and therefore are very useful for communication. Commercial, short-wave, and citizens' band radio are broadcast with radio waves, as is television.