[Resolving angular radiation coefficient. Resolving angle factor]
Ratio of the radiant flux leaving the surface (area element) of one body and arriving at the surface (area element) of another body, taking into account multiple reflections in the system; to the natural radiant flux leaving the surface (area element) of the first body in all possible directions within a hemispherical solid angle.
Comment. 1. We distinguish between "elemental," "local," and "average" resolving angle factors.
2. The medium filling the system is assumed to be transparent.