# 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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# 17-21-080

Me; M

density of exiting radiant flux with respect to area at a point on a real or imaginary surface

where Φe is radiant flux and A is the area from which the radiant flux leaves

Note 1 to entry: For Planckian radiation, Me = σ T4 where σ is the Stefan–Boltzmann constant and T is thermodynamic temperature.

Note 2 to entry: The corresponding photometric quantity is "luminous exitance". The corresponding photon quantity is "photon exitance".

Note 3 to entry: The radiant exitance is expressed in watt per square metre (W⋅m−2).

Note 4 to entry: This entry was numbered 845-01-47 in IEC 60050-845:1987.

Note 5 to entry: This entry was numbered 17-1020 in CIE S 017:2011.

Publication date: 2020-12