Question

1.a)What is a dielectric and dielectric breakdown?

b)What’s leakage current?

c)Define dielectric constant and permittivity

Answer 1

A) dielectric materials does not allow electric current to flow throw them. In other words number of free electrons is very very less to carry the current.

It means that all electrons are strongly bounded to nucleus of the atom.

If we apply a large potential difference across a dielectric medium, the electrons will get release from its strong nuclear attraction and becomes a free electron.

At this potential suddenly more number of electrons will release from nuclear attraction and due to large availability of free electrons, the insulator become conductor.

Hence we can define the dielectric breakdown as the potential applied to a dielectric where it changes its basic character of insulator to conductor.

B) If any device is not properly grounded, the current that flows through a available grounding conductor or through the surface of an insulator is called leakage current.

C) Dielectric constant is the ratio of capacity of parallel plate capacitor with dielectric medium to capacity of same capacitor without dielectric medium.

It can also be defined as the ratio of electrostatic force between two charges separated at a certain distance to the force between same two charges separated at same distance is dielectric medium.

Permittivity: It is the ability of a substance to store electrical energy in it.