Formula: Plate Capacitor Energy    Volume    Electric field (E field)   

Formula: Plate Capacitor
Energy in the E-Field of a Charged Plate Capacitor

Electrical energy

The energy that is 'stored' in the plate capacitor. The energy is stored in the electric field between the plates.


The volume enclosed by the two capacitor plates.

Electric field

The E-field indicates how large the electric force on a test charge would be if it were placed at a specific location between the capacitor plates.

Relative permittivity

Relative permittivity is a dimensionless quantity that characterizes the dielectric (non-conductive material) between the capacitor plates. Depending on the material used, the dielectric can be used to effect the capacitance of the capacitor, for example.

In vacuum, the permittivity by definition has the value \( \varepsilon_{\text r} = 1 \). The water has approximately a value of \( \varepsilon_{\text r} \approx 80 \).

Vacuum Permittivity

The vacuum permittivity is a physical constant that appears in equations involving electromagnetic fields. It has the following experimentally determined value: $$ \varepsilon_0 ~\approx~ 8.854 \, 187 \, 8128 ~\cdot~ 10^{-12} \, \frac{\mathrm{As}}{\mathrm{Vm}} $$

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