Stefan-Boltzmann Law
Stefan-Boltzmann law states that the total emissive power of a blackbody,
Eb,
is given by:
Eb
= s
T4
where s
is the stefan-Boltzmann constant and T is the absolute temperature of
the blackbody. The value of the Stefan-Boltzmann constant is 5.67x10-8 W/m2
K4 or 3.3063
x 10-15 Btu/s.in2.F4.
The spectral variation of blackbody radiation is described by the Planck distribution.
Integrating the Planck distribution law over all wavelengths (l)
gives the Stefan-Boltzmann law.
When a blackbody of a surface area (A) is immersed in a medium with
ambient temperature Ta,
the net rate of heat radiated by the blackbody is given by:
Qradiation = s A ( Ts4
- Ta4 ), Ts> Ta .
where:
Ts = Absolute temperature
of the blackbody
Ta = Absolute temperature
of the surrounding medium (ambient temperature)
Related Topics
Basic
Radiation Definitions
Radiation
Emission from Real Surfaces
Radiation
Exchange Between Surfaces
Examples
of Radiation from Surfaces