| the entire spectrum, considered as a continuum, of all kinds of electric, magnetic, and visible radiation, from gamma rays having a wavelength of 0.001 angstrom to long waves having a wavelength of more than 1 million km. |
The family of electromagnetic waves. The electromagnetic spectrum, starting from the waves with the longest wavelengths (and least energy), consists of radio waves, microwaves, infrared radiation, visible light, ultraviolet radiation, x-rays, and gamma radiation. Members of the family differ from one another only in their wavelength, or frequency. For example, the wavelength of blue light is roughly half that of red light, but the waves corresponding to the two colors are otherwise identical.