Electrostatics of Conductors: Definition, Propteries, Application, Solutions & Class 12 Notes

A conductor is a material that allows the flow of electric charge through it. There are various types of conductors, such as metal, electrolytes, gases, semiconductors, superconductors, etc. Some examples of conductors are metal, silver, aluminium, gold, graphite, etc.

Key results regarding the electrostatics of conductors

Inside a conductor, the electrostatic field is zero

Inside a conductor, the electric field is always zero at an electrostatic equilibrium state. This is because the charges inside the conductor rearrange themselves in such a way that they cancel out any internal electric field.

At the surface of a charged conductor, the electrostatic field must be normal to the surface at every point

At the surface of a conductor, the electric field is always perpendicular to the surface. Due to this, there is no tangential force on the charges and they stay fixed in place on the surface.

The interior of a conductor can have no excess charge in a static situation

In a static condition, the interior of a conductor cannot have an excess charge. When a conductor is neutral, it contains equal amounts of positive and negative charges in every small volume or surface element. If the conductor is charged, the excess charge can only be found on its surface. This property of a conductor is based on Gauss's law, which states that the total electric flux through a closed surface surrounding a volume element inside a conductor is zero. Consequently, there is no net charge within the conductor, and any excess charge is limited to the surface.

The electrostatic potential is constant throughout the volume of the conductor and has the same value (as inside) on its surface

The electrostatic potential inside a conductor is constant throughout its volume and is the same as the potential on its surface. This is because the electric field is zero inside the conductor, and there is no potential difference between any points inside or on the surface. A group of conductor that varies in shape, size, and charge, each conductor has a constant potential. Also, the potential difference of the conductors will vary from one another. In a charged conductor, the electric field appears on its surface. This field leads to an electric field compared to a point outside the surface.

Electrostatic shielding

Electrostatic shielding is a special property of a conductor with cavities. No matter how big or small the cavities are, the electric field within them is always zero. Even if the electric charge or external field are produced on the surface of a conductor, it does not affect the inside. The charge will always be on the surface. Therefore, electrostatic shielding is used to keep sensitive instruments safe from electrical interference.

Below are the applications of electrostatics of conductors.

1. Electrostatic Shielding: Prevents sensitive electronic equipment from external electric fields.
2. Electrostatic Precipitators: Remove pollutants from industrial smoke.
3. Shielding in Cables: Prevents signal loss.
3. Capacitor Design: Storing electric energy.
4. Van de Graff Generator: Generating high voltage for experiments.

5. Lightning Conductors: Directs the lightning to the ground.

Important Links:

Students can find here the links for Class 12 Physics notes.

Class 12 students can find the link to the NCERT solutions for Physics below. Practice the problem to prepare for the exam.