What is Dielectric Constant?

It is also known as Relative permittivity. If two charges q 1 and q 2 are separated from each other by a small distance r. Then by using the coulombs law of forces the equation formed will be

electrostatic 1.28 ———— 2.6

In the above equation electrostatic 1.16 is the electrical permittivity or you can say it, Dielectric constant.

If we repeat the above case with only one change i.e. only change in the separation medium between the charges. Here some material medium must be used. Then the equation formed will be.

electrostatic 2.49 ——2.7
Now after division of equation 2.6 with equation 2.7 we get…
electrostatic 2.50 ——2.8

In the above figure
electrostatic 1.30 is the Relative Permittivity. Again one thing to notice is that the dielectric constant is represented by the symbol(K) but permittivity by the symbol electrostatic 1.30

Now after the division third equation is created. Its we describe this equation then the new definition can be made from this. i.e.
It is the ratio of the force of communication between the two point charges separated from each by a distance using air/Vacuum as a medium to the force of communication between the same charges placed at the same distance and using some material medium.
Faraday has done many experiments on this topic. He found that When we insert some insulating material in the space present between the plates of a capacitor , having its plates fully charged then the capacitance of the capcitor will increase definitely.

bigger electrostatic 2.52
Values of dielectric constant varies with the change in materials. Some of the examples of materials is shown below in the table

Material

Values of K

Air( 1 atm)

1.0006

Amber

2.8

Alcohol

25

Water

81

Hydrogen

1.00026

Germanium

16

Vaccum/Air

1

Metals

Category: Electrostatics

More Questions

2 Responses to " What is Dielectric Constant? "

  1. rohit says:

    if k for mwtal is infinity. then why not thin metal plates are used in capacitor.since C=kC0. then why not metal

  2. sethia says:

    This is because of the large amount of heat produced will eventually melt the metal plate

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