![Stefan–Boltzmann constant
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Not to be confused with Boltzmann constant.
The Stefan–Boltzmann constant (also Stefan's constant), a physical constant denoted by
the Greek letter σ, is the constant of proportionality in the Stefan–Boltzmann law: the total
energy radiated per unit surface area of a black body in unit time is proportional to the fourth
power of the thermodynamic temperature.
The value of the Stefan–Boltzmann constant is given in SI units by
σ = 5.670373(21)×10−8 W m−2 K−4.[1]
In cgs units the Stefan–Boltzmann constant is:
In US customary units the Stefan–Boltzmann constant is:[2]
The value of the Stefan–Boltzmann constant is derivable as well as experimentally
determinable; see Stefan–Boltzmann law for details. It can be defined in terms of the
Boltzmann constant as:
where:
kB is the Boltzmann constant;
h is the Planck constant;
ħ is the reduced Planck constant;
c is the speed of light in vacuum.
The CODATA recommended value is calculated from the measured value of the gas
constant:
where:
R is the Universal gas constant;
NA is the Avogadro constant;
R∞ is the Rydberg constant;](https://image.slidesharecdn.com/stefanboltzmann-140927231747-phpapp01/85/Stefan-boltzmann-Constant-1-320.jpg)
![ Ar(e) is the "relative atomic mass" of the electron;
Mu is the molar mass constant (1 g/mol by definition);
α is the fine structure constant.
A related constant is the radiation constant (or radiation density constant) a which is
given by:[3]
A simple rule to remember the Stefan–Boltzmann constant is to think "5-6-7-8;" and try not
to forget the negative sign before the final eight.](https://image.slidesharecdn.com/stefanboltzmann-140927231747-phpapp01/85/Stefan-boltzmann-Constant-2-320.jpg)
Stefan–boltzmann Constant
- 1. Stefan–Boltzmann constant From Wikipedia, the free encyclopedia Jump to: navigation, search Not to be confused with Boltzmann constant. The Stefan–Boltzmann constant (also Stefan's constant), a physical constant denoted by the Greek letter σ, is the constant of proportionality in the Stefan–Boltzmann law: the total energy radiated per unit surface area of a black body in unit time is proportional to the fourth power of the thermodynamic temperature. The value of the Stefan–Boltzmann constant is given in SI units by σ = 5.670373(21)×10−8 W m−2 K−4.[1] In cgs units the Stefan–Boltzmann constant is: In US customary units the Stefan–Boltzmann constant is:[2] The value of the Stefan–Boltzmann constant is derivable as well as experimentally determinable; see Stefan–Boltzmann law for details. It can be defined in terms of the Boltzmann constant as: where: kB is the Boltzmann constant; h is the Planck constant; ħ is the reduced Planck constant; c is the speed of light in vacuum. The CODATA recommended value is calculated from the measured value of the gas constant: where: R is the Universal gas constant; NA is the Avogadro constant; R∞ is the Rydberg constant;
- 2. Ar(e) is the "relative atomic mass" of the electron; Mu is the molar mass constant (1 g/mol by definition); α is the fine structure constant. A related constant is the radiation constant (or radiation density constant) a which is given by:[3] A simple rule to remember the Stefan–Boltzmann constant is to think "5-6-7-8;" and try not to forget the negative sign before the final eight.