IEVref:845-21-044ID:
Language:enStatus: Standard
Term: radiant intensity
Synonym1:
Synonym2:
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Symbol: Ie
I
Definition: density of radiant flux with respect to solid angle in a specified direction

I e = d Φ e dΩ MathType@MTEF@5@5@+=feaagCart1ev2aqatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbbjxAHXgaruavP1wzZbItLDhis9wBH5garmWu51MyVXgarqqtubsr4rNCHbGeaGqipG0dh9qqWrVepG0dbbL8F4rqqrVepeea0xe9LqFf0xc9q8qqaqFn0lXdHiVcFbIOFHK8Feea0dXdar=Jb9hs0dXdHuk9fr=xfr=xfrpeWZqaaiqaciWacmGadaGadeaabaGaaqaaaOqaaiaadMeadaWgaaWcbaGaaeyzaaqabaGccqGH9aqpdaWcaaqaaiaabsgacqqHMoGrdaWgaaWcbaGaaeyzaaqabaaakeGabaa8niaabsgacqqHPoWvaaaaaa@3F46@

where Φe is the radiant flux emitted in a specified direction, and Ω is the solid angle containing that direction

Note 1 to entry: The definition holds strictly only for a point source.

Note 2 to entry: The distribution of the radiant intensities as a function of the direction of emission, e.g. given by the polar angles (ϑ, φ), is used to determine the radiant flux, Φe, within a certain solid angle, Ω, of a source:

Φ e = Ω I e ( ϑ,φ )sinϑdφ dϑ MathType@MTEF@5@5@+= feaagKart1ev2aqatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbbjxAHX garuavP1wzZbItLDhis9wBH5garmWu51MyVXgaruWqVvNCPvMCG4uz 3bqee0evGueE0jxyaibaieYdi9WrpeeC0lXdh9vqqj=hEeea0xXdbb a9frFj0=OqFfea0dXdd9vqaq=JfrVkFHe9pgea0dXdar=Jb9hs0dXd bPYxe9vr0=vr0=vqpWqaaeaaciWacmGadaGadeaaeaGaauaaaOqaaa baaaaaaaaapeGaeuOPdy0damaaBaaaleaapeGaaeyzaaWdaeqaaOWd biabg2da9maapifabaGaamysa8aadaWgaaWcbaWdbiaabwgaa8aabe aak8qadaqadaWdaeaapeGaeqy0dOKaaiilaiabeA8aQbGaayjkaiaa wMcaaiGacohacaGGPbGaaiOBaiabeg9akjaaykW7caqGKbGaeqOXdO MaaiiOaiaabsgacqaHrpGsaSqaaGWaciab=L6axbqab0Gaey4kIiVa ey4kIipaaaa@550A@ .

Note 3 to entry: The corresponding photometric quantity is "luminous intensity". The corresponding quantity for photons is "photon intensity".

Note 4 to entry: The radiant intensity is expressed in watt per steradian (W·sr−1).

Note 5 to entry: This entry was numbered 845-01-30 in IEC 60050-845:1987.


Publication date:2020-12
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