Explain Dielectric constant.

Dielectric constant: This is also termed as 'Permittivity'. All insulating material possesses an electrical capacitance. Such capacitance of unit depends on dimensions and type of dielectric placed in between the capacitor plates. The capacitance of a parallel plate capacitor may be computed by the formula C = ∈ A/t here ∈ is the permittivity of the material in F/m, A = Area of the plates and t = thickness of dielectric. Therefore permittivity ∈ of a material is a measurement of its capability to form an electrical capacitance of the insulating material, the dimensions of the capacitor being taken equivalent. Dielectric constant or permittivity is not a constant although varies with temperature and frequency and ∈ = C/C_o, here C is capacity in presence of Dielectric and C_o is the capacity in vacuum or air or in the absence of dielectric.