Mumbai university > FE > SEM 1 > Applied Physics 1

Marks: 5M

Year: May 2014

Different Types of Polarizability in Dielectric are as follows:-

• Electronic polarization
• Ionic polarization
• Orientation polarization
• Total Electric polarization

Electronic Polarization:-

• Electronic polarization occurs due to displacement of the center of the negatively charged electron cloud relative to the positive nucleus of an atom by the electric field.

• When an external electric field is applied, like by placing the dielectric material between the two plates of the parallel plate capacitors, the positively charged nucleus is attracted towards the negative side of the electric field and the negatively charged electron cloud is shifted towards the positive plate.

• In fig. 3.12A, you can see that the centroid of positively charged nucleus and negatively charged electron cloud coincide.

• Fig. 3.12B shows the atom when placed in an external electric field. As you can see from the figure that the centroid of negatively charged electron cloud moves away from the positively charged nucleus thus generating a dipole moment.

• The induced dipole moment is given by

• Mono-atomic gases exhibit this kind of polarization.

• Electronic Polarizability is proportional to the volume of atoms and independent of the temperature.