The Electromagnetic Spectrum

The electromagnetic spectrum is the distribution of electromagnetic radiation according to energy or equivalently, by virtue of the relations in the previous section, according to frequency or wavelength. The following table gives approximate wavelengths, frequencies, and energies for selected regions of the spectrum.

Spectrum of Electromagnetic Radiation
Region Wavelength
(Angstroms)		 Wavelength
(centimeters)		 Frequency
(Hz)		 Energy
(eV)
Radio > 109 > 10 < 3 x 109 < 10-5
Microwave 109 - 106 10 - 0.01 3 x 109 - 3 x 1012 10-5 - 0.01
Infrared 106 - 7000 0.01 - 7 x 10-5 3 x 1012 - 4.3 x 1014 0.01 - 2
Visible 7000 - 4000 7 x 10-5 - 4 x 10-5 4.3 x 1014 - 7.5 x 1014 2 - 3
Ultraviolet 4000 - 10 4 x 10-5 - 10-7 7.5 x 1014 - 3 x 1017 3 - 103
X-Rays 10 - 0.1 10-7 - 10-9 3 x 1017 - 3 x 1019 103 - 105
Gamma Rays < 0.1 < 10-9 > 3 x 1019 > 105

In the table, the notation "eV" stands for electron-volts, a common unit of energy measure in atomic physics. Animation: regions of the electromagnetic spectrum