Electric Displacement

Physics

definition

Electric Displacement

Electric displacement is given as:

where:
External electric field
Polarisation 
Permittivity of free space

It is related to the free charge density by,

Note:
1. Electric Displacement is directly related to the free surface charge density in a medium instead of the electric field.
2. On change of medium of an electric field, electric field changes but electric displacement remains the same.

definition

Relationship between Electric Displacement and Electric field

Electric displacement is given by:

where
Permittivity of the medium