permittiviteitsconstante
Permittiviteitsconstante, in electromagnetism often referred to simply as the permittivity, is the property of a material that relates the electric displacement field D to the electric field E: D = ε E. The absolute permittivity ε has units of farads per meter (F/m). In vacuum, the vacuum permittivity ε0 is a fundamental constant, approximately 8.854187817×10^-12 F/m. For a homogeneous, isotropic dielectric, ε = εr ε0, where εr is the relative permittivity (the dielectric constant) of the material and is dimensionless.
The permittivity determines how electric fields interact with a medium. It appears in Coulomb’s law for charges
In general, ε can be frequency-dependent and, in anisotropic materials, represented by a tensor εij. Materials exhibit