Symbols:Greek/Epsilon/Vacuum Permittivity

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Vacuum Permittivity


The vacuum permittivity is the physical constant denoted $\varepsilon_0$ defined as:

$\varepsilon_0 := \dfrac {e^2} {2 \alpha h c}$


$e$ 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 .



Vacuum permittivity can also be seen denoted as $\Gamma_e$ in some older works.

The $\LaTeX$ code for \(\Gamma_e\) is \Gamma_e .