Electrostatics

Electrostatics

What is Electrostatics? 

Study of stationary electric charges at rest is known as electrostatics. An electroscope is used to detect the charge on a body. Pith ball electroscope is used to detect a charge and to know the nature of the charge. Gold leaf electroscope which was invented by Bennet detects a charge and the nature of the charge and determines the quantity of the charge

〽️Conductors, Insulators, and Semiconductors

✏️ A body in which electric charge can easily flow through is called conductor (e.g. metals).

✏️ A body in which electric charge cannot flow is called insulator or dielectric. (e.g. glass, wool, rubber, plastic, etc.)

✏️ Substances which are intermediate between conductors and insulators are called semiconductors. (e.g. silicon, germanium, etc)

〽️Dielectric Strength: It is the minimum field intensity that should be applied to break down the insulating property of insulator.

✏️ Dielectric strength of air = 3 x 106 V/m

✏️ Dielectric strength of Teflon = 60 × 106 Vm–1

The maximum charge a sphere can hold depends on the size and dielectric strength of the medium in which the sphere is placed.

✏️ The maximum charge density of a sphere of radius ‘R’ in terms of electric intensity E at a distance in free space is Eε0(R/r)2.

✏️ When the electric field in the air exceeds its dielectric strength air molecules become ionized and are accelerated by fields and the air becomes conducting.