Radiant flux

The radiant energy emitted, reflected, transmitted, or received, per unit time.

In radiometry, radiant flux or radiant power is the radiant energy emitted, reflected, transmitted or received, per unit time, and spectral flux or spectral power is the radiant flux per unit frequency or wavelength, depending on whether the spectrum is taken as a function of frequency or of wavelength. The SI unit of radiant flux is the watt (W), that is the joule per second (J/s) in SI base units, while that of spectral flux in frequency is the watt per hertz (W/Hz) and that of spectral flux in wavelength is the watt per meter (W/m)—commonly the watt per nanometre (W/nm).

Key Terms

radiant energy
radiant flux
radiant power
spectral flux
spectral power
unit time

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Radiant flux
Radiant power


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Sources & Credits

Last modified on June 22 2020
Content adapted from Wikipedia
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