# Electrostatics

## Overview of electrostatics and electricity

Electrostatics involves electric charges namely positive and negative charges, the forces between them which is known as electric force, the field that surrounds them, and their behavior in materials. Coulomb's law is the simple relation that governs electrostatic interactions and the field around the charges is described using the concept of the electric field. Coulomb's law is an inverse square law which gives the force between two charges kept at some distance (say r ) apart from each other. Like Coulomb's law, the law of gravitation is also an inverse square law but gravitational interactions are only attractive in nature and electrical interactions are attractive as well as repulsive depending on nature if interacting charges. Charges of the same kind repel each other and charge different kinds, i.e. one charge positive and other negatives, attract each other. One more thing electric interactions are much stronger then gravitational interactions and gravitational force are almost negligible in comparison to the forces of electric origin. This is always true when we study the interactions of atomic and subatomic particles. But when we study objects very large in size say a person, a planet or satellites, the net governing force, in this case, is a gravitational force not electric.

Now coming to the properties of electric charges we know that electric charge is quantized and it also obeys the law of conservation means total charge remains conserved. In what we say electrostatic interactions electric charges are at rest in our frame of reference. Now think what happens when we are at rest in our frame of reference and charge under consideration is moving with velocity v with respect to us such a moving charge leads to the origin of magnetism which we will discuss in a later section.

Again a question what is electricity. Electricity deals with stationary and moving electric charges, the actions of force between these charges, and the electric and magnetic fields generated by them. Electrostatics is simply electricity at rest. Electricity is the backbone of the modern society in which we use various instruments which depends on electric current for their functioning and without it, we would not have telephones, television, household appliances and many more gadgets which are now part of our daily life. In electricity, we study the motion of electric charges, or electric currents and also the voltages that produce currents and the ways to control currents.

We have learned about what electrostatics is and what we study in it. Now we will discuss why we study electrostatics and where it finds its applications. Electric interactions are of immense importance in chemistry and biology and have many technological applications. Concepts of electricity proved to be of basic importance for studying atomic physics, nuclear physics, and solid-state physics. It also finds importance in studying advanced level physics.