Preferred Label : radiance;
Detailed label : radiance, L;
IUPAC definition : radiant power, P, u leaving or passing through /u a small transparent element of
surface in a given direction from the source about the solid angle Ω, divided by the
solid angle and by the orthogonally projected area of the element in a plane normal
to the given beam direction, dS dS cos θ;
Scope note : equivalent to l ¿ ¿ l¿ , wherel¿is the spectral radiance at wavelength
¿.; for a parallel beam it is the radiant power, p, of all wavelengths leaving or passing
through a small element of surface in a given direction from the source divided by
the orthogonally projected area of the element in a plane normal to the given direction
of the beam, ¿.mathematical definition in this case: s¿ pif the radiant power
is constant over the surface area considered, p s¿ . si unit
is w m-2.; mathematical definition: l ¿ s¿ p ¿ s¿ p for a
divergent beam propagating in an elementary cone of the solid angle¿containing the
direction ¿.si unit is w m-2 sr-1.;
Origin ID : R05037;
See also
radiant power, P, u leaving or passing through /u a small transparent element of
surface in a given direction from the source about the solid angle Ω, divided by the
solid angle and by the orthogonally projected area of the element in a plane normal
to the given beam direction, dS dS cos θ
