what is dielectric? write its different types.
Answers
Answer:
Dielectrics are non-conducting substances which are the insulating materials and are bad conductor of electric current. Dielectric materials can be made to hold an electrostatic charge while dissipating minimal energy in the form of heat. Examples of dielectric are Mica, Plastics, Glass, Porcelain and Various Metal Oxides and even dry air is also example of dielectric.
Dielectrics can be classified as:
Polar Molecules
Non-Polar Molecules
Polar Molecules: Polar Molecules are those type of dielectric in which the possibilities that the positive and negative molecules will coincide with each other is null or zero
The reason why the polar molecules do not coincide with each other is due to their shape, that is they all are asymmetric in shape.
Examples: H2O, CO2, NO2 etc.
When the electric field is not present that is if it is absent then, it causes the electric dipole moment of these molecules in random direction which is responsible for cancellation of these molecules with each other. So, the average dipole moment is zero.
If the external electric field is present, the molecules assemble in the same direction as electric field.
Non-Polar Molecule, unlike polar molecules in non-polar molecules the center of positive charge and negative coincide, that is it is not zero. The molecule then has no permanent (or intrinsic) dipole moment
Example: O2, N2, H2 etc.
When a dielectric slab is placedin an electric field, then the dipole moment is gained by the molecule and the dielectric is said to be polarised.
The Electric Polarization is dipole moment per unit volume of a dielectric material.
The polarization is denoted by P.