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Question
With the help of neat diagram, explain how non-polar dielectric material is polarised in external electric field of increasing intensity. Define polarisation in dielectrics.
Solution
If a dielectric (non-polar) molecule is placed in an external electric field, a small induced dipole moment is created because the positive charge in each atom is pushed in the direction of the field and negative charge is pushed in the opposite direction as shown in the figure.
Polarization is the amount of induced surface charge per unit area or the surface density of polarization charges appearing at right angles to applied external electric field.
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