Stefan's law


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Stefan's law

(steff -ănz) (Stefan-Boltzmann law) The law relating the total energy, E , emitted over all wavelengths, per second, per unit area of a black body, with the temperature, T , of the body:
E = σT 4

σ is Stefan's constant, which has the value 5.6705 × 10–8 W m–2 K–4. The law can be derived from Planck's radiation law (see black body), but was first deduced by Josef Stefan in 1879 and then derived from thermodynamics by Ludwig Boltzmann in 1884. See also luminosity.

References in periodicals archive ?
It is known that the emissivity of gases can fall with temperature in clear violation of Stefan's law [24].
In some climate models [5, 6], the radiation which the Earth emits is deduced by applying Stefan's law [12], at a given effective temperature, thereby treating the globe as a uniform blackbody source.
Note, in this regard, that Stefan's law invokes a 4th power temperature dependence [12].
Consequently, we can see that Stefan's law does not hold for gases [7].
In this essay, it becomes apparent that Stefan's Law of thermal emission does not hold for liquids and gases.