question_answer

Directions: (46-50)

Polarisation of Dielectric

When an insulator is placed in an external field, the dipoles become aligned. Induced surface charges on the insulator establish a poarization field \[{{\overrightarrow{E}}_{i}}\]in its interior.

The net field \[\overrightarrow{E}\] in the insulator is the vector sum of \[{{\overrightarrow{E}}_{0}}\]and\[{{\overrightarrow{E}}_{i}}\], as shown in the figure.

[a]

[b]

[c]

On the application of external electric field, the effect of aligning the electric dipoles in the insulator is called polarisation and the field \[{{\overrightarrow{E}}_{i}}\], is known as the polarization field. The dipole moment per unit volume of the dielectric is known as polarization \[\left( \overrightarrow{P} \right)\].

For linear isotropic dielectrics, \[\overrightarrow{P}=\chi \overrightarrow{E}\], where 7 \[\chi =\]electrical susceptibility of the dielectric medium.

Which among the following is an example of polar molecule?

A) \[{{O}_{2}}\]

B) \[{{H}_{2}}\]

C) \[{{N}_{2}}\]

D) \[HCl\]