## Capacitance

Unit
Electric capacitance determines how much charge the spherical capacitor can store separately when a certain voltage is applied between the two electrodes of the capacitor.

Unit
Radius of the inner charged sphere of the spherical capacitor.

Relative permittivity depends on the medium and indicates the permeability of the electric field. In vacuum it has the value: $$\varepsilon_r ~=~ 1$$. The capacitance of the spherical capacitor can be increased by using a different medium (e.g. air, water, glass) between the inner and outer sphere.
Permittivity of free space is a natural constant and has the value: $$\varepsilon_0 = 8.854 \cdot 10^{-12} \, \frac{\text{As}}{\text{Vm}}$$.