Question

What is polarization of charge? With the help of a diagram show why the electric eld between the plates of the capacitor reduces on introducing a dielectric slab. Dene dielectric constant on the basis of these fields.

Answer 1

Polarisation of charge: When an dielectric material is placed in the external electric field then, charge is induced in the dielectric material, hence an induced electric field is set up between the plates in the opposite direction to the external field. This is called polarisation of the charge.

This fig, shows the dielectric slab between the plates of the capacitor. Since an opposite field is induced between the plates, hence net electric field is decreased between the plates of the capacitor. dieletric constant of the capacitor is k.