Name: Capacitance of a Parallel Plate Capacitor
Uploaded: 2019-07-19
Duration: 4 min 13 s
Description: Capacitors are available in various shapes and sizes. In this video, we will learn how to calculate the capacitance of a parallel plate capacitor.

Question

Explain the behaviour of dielectrics in an external field.

Accepted Answer

Dielectrics, in general, can be described as materials that are very poor conductors of electric current. They are basically insulators and contain no free electron. Dielectrics can be easily polarised when an electric field is applied to it. Thus, their behaviour in an electric field is entirely different from that of conductors.

When an external electric field is applied, there is some displacement of the bound charges, thus creating small electric dipoles within the dielectric. This phenomenon is known as polarisation. The electric field inside and outside a dielectric gets modified due to the presence of dipoles.

A dielectric may be made up of polar or non-polar molecules. But the net effect of an external field is almost the same, i.e., the external field will compel the molecules to align their dipole moments along its own direction. Although the dielectric is polarised, yet as a whole, it remains electrically neutral.

Explain the behaviour of dielectrics in an external field.

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