| quotient of the radiant energy dR incident on a sphere of cross-sectional area da |
Ψ = dR/da
Note 1 to entry: It is the time-integral of the energy flux.
Note 2 to entry: This quantity is expressed in joules per square metre (J/m2).
Note 3 to entry: This entry was numbered 393-14-28 in IEC 60050-393:2003.