radiant exitance, \(M\)

Synonym: radiant emittance
https://doi.org/10.1351/goldbook.R05041
Radiant power, P, emitted at all wavelengths by an element of surface containing the source point under consideration divided by the area of the source. SI unit is W m-2.
Notes:
  1. Mathematical definition: \(M = \text{d}P/\text{d}S\). If the @R05046-2@ \(P\) is constant over the surface area considered, \(M = P/S\).
  2. Equivalent to the integration of the @R05046-3@ leaving a source over the solid @A00346@ and over the whole @W06659@ range. Mathematical definition: \(M = \int_{\lambda}M_{\lambda}\, \text{d}\lambda\), where \(M_{\lambda}\) is the @S05825@ at @W06659@ \(\lambda\).
  3. Same as spherical radiant @E02264@. Formerly called radiant emittance.
Source:
PAC, 2007, 79, 293. 'Glossary of terms used in photochemistry, 3rd edition (IUPAC Recommendations 2006)' on page 409 (https://doi.org/10.1351/pac200779030293)