power emitted, transferred or received as radiation. SI unit is J s-1 = W.
- Mathematical definition: P = dQ/dt. If the @R05039@ Q is constant over the time interval, P = Q/t.
- In @R05115@, flux (Φ) is used with the same units as P. The symbol Φ is reserved for @Q04991@ in @P04588@. Therefore, the use of flux (Φ) is not recommended.
PAC, 2007, 79, 293. 'Glossary of terms used in photochemistry, 3rd edition (IUPAC Recommendations 2006)' on page 410 (https://doi.org/10.1351/pac200779030293)