Symbols:Greek/Epsilon/Vacuum Permittivity
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Vacuum Permittivity
- $\varepsilon_0$
The vacuum permittivity is the physical constant denoted $\varepsilon_0$ defined as:
- $\varepsilon_0 := \dfrac {e^2} {2 \alpha h c}$
where:
- $e$ is the elementary charge
- $\alpha$ is the fine-structure constant
- $h$ is Planck's constant
- $c$ is the speed of light defined in $\mathrm m \, \mathrm s^{-1}$
Of the above, only the fine-structure constant $\alpha$ is a measured value; the others are defined.
It can be defined as the capability of an electric field to permeate a vacuum.
From Value of Vacuum Permittivity, it has the value:
- $\varepsilon_0 = 8 \cdotp 85418 \, 78128 (13) \times 10^{-12} \, \mathrm F \, \mathrm m^{-1}$ (farads per metre)
The $\LaTeX$ code for \(\varepsilon_0\) is \varepsilon_0
.
Variant
- $\Gamma_e$
Vacuum permittivity can also be seen denoted as $\Gamma_e$ in some older works.
The $\LaTeX$ code for \(\Gamma_e\) is \Gamma_e
.
Sources
- 1969: J.C. Anderson, D.M. Hum, B.G. Neal and J.H. Whitelaw: Data and Formulae for Engineering Students (2nd ed.) ... (previous) ... (next): $3.$ Physical Constants