radiant exitance, \(M\)

Synonym: radiant emittance
@[email protected], \(P\), 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 \(\text{W m}^{-2}\).
  1. Mathematical definition: \(M = \text{d}P/\text{d}S\). If the @[email protected] \(P\) is constant over the surface area considered, \(M = P/S\).
  2. Equivalent to the integration of the @[email protected] leaving a source over the solid @[email protected] and over the whole @[email protected] range. Mathematical definition: \(M = \int_{\lambda}M_{\lambda}\, \text{d}\lambda\), where \(M_{\lambda}\) is the @[email protected] at @[email protected] \(\lambda\).
  3. Same as spherical radiant @[email protected] Formerly called radiant emittance.
PAC, 2007, 79, 293. (Glossary of terms used in photochemistry, 3rd edition (IUPAC Recommendations 2006)) on page 409 [Terms] [Paper]