Stefan-Boltzmann constant

The Stefan-Boltzmann constant is a constant of proportionality, σ = [math] 5.67 \times 10^{-8} \frac{W}{m^2K^4}[/math] which gives how much power is radiated by an object at a given temperature.[1] It is a physical constant involved in the calculations regarding blackbody radiation in the Stefan-Boltzmann law. The constant defines the power per unit area emitted by a blackbody as a function of its temperature.[2]

This constant was first calculated in 1879 by physicist Josef Stefan, and later again in 1884 by physicist Ludwig Boltzmann who took a more thermodynamic approach.[3] The Stefan-Boltzmann constant isn't a fundamental constant but is actually made of other constants (see the derivation from the Plank radiation formula on hyperphysics), which are used together often enough to be treated as a single constant.


References

  1. Kenneth Krane. Modern Physics, 3rd ed. Hoboken, NJ, USA: John Wiley & Sons, 2012.
  2. Marc L. Kutner. Astronomy: A Physical Perspective, 2nd ed. New York, USA: Cambridge University Press, 2003
  3. Encyclopedia Brittanica. (2015, Mar.7). Stefan-Boltzmann Law [Online]. Available: http://www.britannica.com/EBchecked/topic/564843/Stefan-Boltzmann-law