Planck's Law - This is a derived formula, from the German physicist Max Planck, that portrays the amount of radiation emitted by a blackbody as theoretically determined by its temperature. It is an equation that produces a curve, termed Planck's blackbody radiation curve, which illustrates that the warmer a body is, the greater is its blackbody emission at each wavelength and the shorter is the wavelength at which emissions peak.
[An Introduction to Three-Dimensional Climate Modeling; Warren Washington and Claire Parkinson; page 13; 1986; University Science Books; Mill Valley, California.]
[Atmospheric Science; John Wallace and Peter Hobbs; pages 281 and 287; 1977; Academic Press, Inc; New York.] 
Atmospheric Chemistry Glossary