Editing Relative permittivity (section)

{{Short description|Measure of the electric polarizability of a dielectric, compared with that of a vacuum}}
{{Relative permittivity table}}
[[File:Water relative static permittivity.svg|thumb|right|Temperature dependence of the relative static permittivity of water]]

The '''relative permittivity''' (in older texts, '''dielectric constant''') is the [[permittivity]] of a material expressed as a ratio with the [[vacuum permittivity|electric permittivity of a vacuum]]. A [[dielectric]] is an insulating material, and the dielectric constant of an insulator measures the ability of the insulator to store electric energy in an electrical field.

Permittivity is a material's property that affects the [[Coulomb force]] between two point charges in the material. Relative permittivity is the factor by which the electric field between the charges is decreased relative to vacuum.

Likewise, relative permittivity is the ratio of the [[capacitance]] of a [[capacitor]] using that material as a [[dielectric]], compared with a similar capacitor that has vacuum as its dielectric. Relative permittivity is also commonly known as the dielectric constant, a term still used but deprecated by standards organizations in engineering<ref name=IEEE1997/> as well as in chemistry.<ref name="IUPAC"/>