
324 Heat Transfer: Thermal Management of Electronics
where I
e
is the total intensity of the emitted radiation at all wavelengths,
(13.14)
13.2 BLACKBODY RADIATION
A blackbody is a conceptual surface dened as the perfect emitter and absorber of
radiation energy. It is dened by the following three characteristics:
1. A blackbody emits maximum radiation energy at a given temperature and
wavelength. No surface can emit more radiation than a blackbody at the
same temperature.
2. A blackbody absorbs all the radiation energy that reaches its surface.
3. A blackbody emits radiation energy uniformly in all directions. This means