Chapter-2|Electrostatic Potential and Capacitance| NCERT 12th Physics:
Electrostatics of Conductors:
Conductors are the materials through which electric charges can flow easily.
When a conductor is placed in electrostatic field, the conductors show the following properties.
1. Inside a conductor, electrostatic field is zero.
2. At the surface of a charged conductor, electrostatic field must be normal to the surface at every point.
3. The interior of the conductor can have no access charge in the static situation.
4. Electrostatic potential is constant throughout the volume of the conductor and has the same value (as inside) on its surface.
5. Surface charge density could be different at different points.
The phenomenon of protecting a certain region of space from external electric field is called electrostatic shielding.
When we placed a hollow conductor in an external electric field, then electric field inside the conductor is zero.
So to protect some instruments from external field, They are enclosed in hollow conductor.
These are the substance which do not allow physical movement of electric charges through them when an external field is applied.
For Exp- Diamond, Glass, Wax, etc.
The rubbed insulators were able to retain charges placed on them, So they were called dielectrics.
Insulators are also called dielectrics, when an electric field is applied, induced charges appear on the surface of the dielectrics. Hence, it can be said that dielectrics are the insulating materials which transmit the electric effect without conducting.