# Basic Knowledge of Polarisation of Dielectrics

Physics

## definition

### Polarisation

When an electric field is applied there is small displacement of bound charges creating small  electric dipoles within the dielectric. This phenomenon is called Polarization.
The polarisation of a region is defined as the dipole moment per unit volume.
For linear isotropic dielectrics, it is given by

where is the dielectric susceptibility of the dielectric medium

## definition

### Electric susceptibility

Polarisation in a dielectric is given by:
where
Electric susceptibility of the medium
External electric field
Electric susceptibility is related to the molecular properties of the substance.
It is also given by:

where dielectric constant of the medium