Definition:Stefan-Boltzmann Constant

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Definition

The Stefan-Boltzmann constant is the constant of proportion that defines the intensity of the thermal radiation emitted by a body in terms of that body's temperature:

$\sigma := \dfrac {2 \pi^5 k^4} {15 c^2 h^3}$

where:

$k$ is Boltzmann's constant
$c$ is the speed of light
$h$ is Planck's constant.




Symbol

$\sigma$

The symbol for the Stefan-Boltzmann constant is $\sigma$.


Its $\LaTeX$ code is \sigma .


Dimension

The Stefan-Boltzmann constant has the dimension $\mathsf {M T^{-3} \Theta^{-4} }$.


Units

The SI unit for the Stefan-Boltzmann constant is given in watts per square metre per kelvin to the $4$th:

$\mathrm {W \, m^{-2} \, K^{-4} }$


Value

The value of the Stefan-Boltzmann constant is:

\(\ds \sigma\) \(\approx\) \(\ds 5 \cdotp 67037 \, 4419 \ldots \times 10^{-8}\) $\mathrm {W \, m^{-2} \, K^{-4} }$ \(\quad\) in SI units
\(\ds \) \(\approx\) \(\ds 5 \cdotp 67037 \, 4419 \ldots \times 10^{-5}\) $\mathrm {erg \, cm^{-2} \, s^{-1} \, K^{-4} }$ \(\quad\) in CGSunits
\(\ds \) \(\approx\) \(\ds 4 \cdotp 76 \times 10^{-13}\) $\mathrm {btu \, ft^{-2} \, \rankine^{-4} }$ \(\quad\) in FPS units


Also see


Source of Name

This entry was named for Josef Stefan and Ludwig Eduard Boltzmann.


Sources