Absorption
The process of converting radiation intercepted by matterto internal thermal energy.
Absorptivity
Fraction of the incident radiation absorbed by matter.Equations 12.39, 12.40, and 12.43.Modifiers: directional, hemispherical, spectral, total.
Blackbody
The ideal emitter and absorber. Modifier referring to ideal behavior.
Denoted by the subscript b
Diffuse
Modifier referring to the directional independence of the intensity associated with emitted, reflected, or incident radiation.
Directional
Modifier referring to a particular direction.Denoted by the subscript .