Dielectric constant. Dielectric constant of a medium is defined as the ratio of the electrostatic force between the two charges placed at a certain distance apart in vacuum to the force between the same two charges placed at the same distance apart in the medium. Dielectric constants of some common media are as follows:
Vacuum - 1.00000
Air - 1.00054
Water - 78
Paper - 3.5
Mica - 5.4
