TYPES OF POLARIZATION

Engineering physics

1. TYPES OF POLARIZATION MADE BY AAKASH TOMAR ENG21DS0001

2. WHAT IS DIELECTRIC POLARIZATION When an electric field is applied across a dielectric material then the dielectric material becomes polarized . This mechanism is called dielectric polarization.

3. TYPES OF POLARIZATION There are four types of polarization Electronic polarization Ionic polarization Orientational polarization Space charge polarization

4. Electronic Polarization

5. Expression for Electronic Polarization

6. Hence electronic polarizability is directly proportional to cube of the radius of the atom

7. Ionic polarization

8. Orientational Polarization When an electric field is applied on an dielectric material with permanent dipole moment ( μ ), the applied field tries to orient the dipole along its direction . The orientational polarization is given by αo is orientation polarizability

9. Thus the orientational polarizability is a temperature dependent term and is inversely proportional to the absolute temperature of the dielectric material. It is slow process compare to ionic and electronic polarization. All the molecular dipoles are oriented randomly when there is no Electric field. In the presence of the electric field these dipoles orient themselves in the direction of field as a result the net dipole moment becomes enormous.

10. Space charge polarization When an electric field is applied to a bulk dielectric material the charges in the material diffuse to a considerable distance with response to the applied field . This is very slow process and contribution to the total polarization from space charge polarization is neglizible .

11. Total Polarization Total Polarization is the sum of polarizations due to electronic ,ionic, orientational and space charge polarizabilities.

12. THANK YOU