Electric and magnetic field variations intime and space that propagate through a medium or a vacuum with the wave'spropagation, electric field, and magnetic field vectors forming anorthogonal triad. W
aves in this category are detected by having their fieldquantities measured.
The distribution of electromagnetic waves or radiation arranged according to wavelength and frequency. Electromagnetic wave energy is the product of frequency and wavelength, and thus is a related mea
ns of categorizing the spectrum. Although the Sun's peak radiative output is in visible light band in the midst of the spectrum, the Sun emits energy ranging from short wavelength (high energy) gamma rays to long wavelength (low energy) radio waves.
The electromagnetic (EM) spectrum is the range of all possible electromagnetic radiation. The electromagnetic spectrum (usually just spectrum) of an object is the characteristic distribution of electr
omagnetic radiation from that object.