# e-ILV

The e-ILV provides free access to all the terms and definitions contained in the international standard CIE S 017:2020 ILV: International Lighting Vocabulary, 2nd edition.

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# 17-21-040

photon flux

Φp; Φ

rate of photon number per time interval

where Np is photon number, transmitted or received, and t is time

Note 1 to entry: Photon flux, Φp, is related to radiant flux, Φe, of monochromatic radiation by

where h is the Planck constant, and ν is the frequency of the corresponding electromagnetic wave.

Note 2 to entry: For a beam of radiation whose spectral distribution is or , the photon flux can be expressed by , where h is Planck's constant and c0 is the speed of light in vacuum.

Note 3 to entry: The corresponding radiometric quantity is "radiant flux". The corresponding photometric quantity is "luminous flux".

Note 4 to entry: The photon flux is expressed in second to the power minus one (s−1).

Note 5 to entry: This entry was numbered 845-01-26 in IEC 60050-845:1987.

Note 6 to entry: This entry was numbered 17-927 in CIE S 017:2011.

Publication date: 2020-12