6
General Laws
of Radiation
¥All objects above 0 K emit radiant
energy
¥Hotter objects radiate more energy per
unit area than
colder objects, result of 
Stefan-Boltzman Law¥The hotter the radiating body, the
shorter the wavelength
of maximum radiation, result of WienÕs Displacement Law¥Objects that are good absorbers of
radiation are also
good emittersÉtodayÕs lecture!