What is the Stefan-Boltzmann Constant?
The Stefan-Boltzmann constant is used mostly in equations involving the Stefan Boltzmann law, which states that the energy radiated per unit of surface area of a black body per unit time is proportional to the fourth power of the thermodynamic temperature of that body. One could apply this law to calculate the temperature of the sun, for example. In its standard use, the Stefan-Boltzmann constant uses the symbol σ, and has units of W/(m2.K4). Its value is 5.670400×10-8. One can also derive the Stefan-Boltzmann constant both by experiment and from the standard Boltzmann constant. Mathematically, this amounts to the following: σ = (2.π5.kb4) / (15.h3.co2) where kb is the Boltzmann constant (1.3×10-23 J/K), h is the Planck constant (6.26×10-34 J.s), and co is the speed of light (3×108 m/s). The Stefan-Boltzmann law uses this constant in the following way, relating the radiant flux of a black body to temperature with this formula: j* = σT4 where j* is the radiant flux of a perfect black bo
