electromagnetic spectrum

[Image:spectrum.png|right|frame|Legend γ = Gamma rays HX = Hard X-rays SX = Soft X-Rays EUV = Extreme ultraviolet NUV = Near ultraviolet Visible light NIR = Near infrared MIR = Mid infrared FIR = Far infrared  Radio waves EHF = Extremely high frequency (Microwaves) SHF = Super high frequency (Microwaves) UHF = Ultra high frequency VHF = Very high frequency HF = High frequency MF = Medium frequency LF = Low frequency VLF = Very low frequency VF = Voice frequency ELF = Extremely low frequency]]
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Noun
1. the entire frequency range of electromagnetic waves
(hypernym) spectrum
(part-meronym) radio frequency

The range of frequencies of electromagnetic radiation from zero to infinity. Note: The electromagnetic spectrum was, by custom and practice, formerly divided into 26 alphabetically designated bands. This usage still prevails to some degree. However, the ITU formally recognizes 12 bands, from 30 Hz to 3000 GHz. New bands, from 3 THz to 3000 THz, are under active consideration for recognition. Refer to the figure below.

the range of electromagnetic wave - wavelengths. There is no theoretical limit on the range of wavelengths in the electromagnetic spectrum.

The entire range of electromagnetic radiation . It ranges from the longest wavelength radiation, radio waves, through microwaves , infrared, visible light, ultravolet, x-rays and finally to the shortest wavelength radiation, gamma rays. Although all the forms of electromagnetic radiation propagate at the speed of light , the shorter wavelength radiations carry more energy per photon than the longer wavelength radiations.