Question

What is the polarization of a dielectric on application of electric field?

Answer 1

When a dielectric material is subjected to an electric field, the molecules or atoms within the material respond to the field by reorienting or shifting their internal charges. This process is called polarization.

Here's how it works:

1. Polarization in Dielectrics: A dielectric material consists of atoms or molecules that have positive and negative charges. In the absence of an external electric field, these charges are randomly distributed, and the material has no net dipole moment (i.e., it's not polarized).
   

1. Effect of Electric Field: When an external electric field is applied, it causes the positive and negative charges in the atoms or molecules to move in opposite directions. This results in the formation of electric dipoles. The alignment of these dipoles in the direction of the electric field is called polarization.
   

1. Polarization Vector: The degree of polarization of a dielectric is usually described by a polarization vector (P), which represents the dipole moment per unit volume of the material. The polarization depends on the strength of the applied electric field and the properties of the dielectric material.
   

1. Dielectric Constant: The material's ability to polarize in response to the applied electric field is quantified by its dielectric constant (ε). A higher dielectric constant means the material can polarize more easily and store more electrical energy.
   

In simpler terms:

1. The electric field "distorts" the charge distribution in the dielectric material, creating tiny dipoles (pairs of positive and negative charges).
   

1. This distortion is what we call polarization.
   

1. The stronger the electric field, the greater the polarization, as more dipoles align in the direction of the field.
   

This process is crucial in many applications, such as capacitors, where dielectrics are used to increase the capacitor's ability to store charge.