IEVref: | 723-08-27 | ID: | |

Language: | en | Status: Standard | |

Term: | luminous flux (radiated by a source) | ||

Synonym1: | |||

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Symbol: | Ф
| ||

Definition: | quantity defined by $\Phi ={K}_{\text{m}}{\displaystyle \underset{0}{\overset{\infty}{\int}}V(\lambda )P(\lambda )}\mathrm{d}\lambda $ where:
NOTE – In the SI system of units, where | ||

Publication date: | 1997-03 | ||

Source | |||

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Internal notes: | 2016-03-08: <i>Ф</i> corrected to italic in accordance with the other entries in the IEV. JGO 2016-03-09: "a magnitude" replaced by "quantity" and <i>λ</i> formatted as italic by agreement with VT 60050 convenor. JGO 2017-06-02: Cleanup - Remove Attached Image 723-08-27.gif | ||

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Domain5: |

$\Phi ={K}_{\text{m}}{\displaystyle \underset{0}{\overset{\infty}{\int}}V(\lambda )P(\lambda )}\mathrm{d}\lambda $

where:

*P*(*λ*) is the power spectral density radiated by the source at wavelength *λ*;

*V*(*λ*) is the spectral luminous efficiency for photopic vision;

*K*_{m} is a constant
*λ*) is expressed in watts per metre, the luminous flux *Ф* is expressed in lumens, and *K*_{m} = 683 lm/W.