Electrostatics: Definition, Coulomb’s Law, Electric Feild, Examples and More

Electrostatics is the study of stationary electric charges. Electric charge is the charge associated with matter that causes it to create and experience a magnetic and electric effect. When a plastic rod is rubbed with fur or a glass rod is rubbed with silk, pieces of paper are attracted, indicating that both rods are electrically charged.

Electrostatics is a branch of physics that studies electromagnetic phenomena that occur when electric charges are at rest, i.e. when there are no moving charges after a static equilibrium has been formed. The electrostatic phenomena in physics refer to the behaviour of slow-moving or stationary electric charges.

Furthermore, because this phenomenon is caused by the forces exerted by electric charges on one another, it is defined by Coulomb's Law of Electrostatics. As a result, understanding the idea of electrostatic requires knowledge of electric charge and Coulomb's Law.

On that note, let’s learn about exploring electrostatics (Coulomb’s law of Electrostatics) and important related concepts with examples for better understanding.

Coulomb's Law

An experimental law governs the calculation of the force between two stationary charges. Coulomb's law states that opposite charges and like charges always repel one another, with the force of the repelling force being inversely proportional to the square of the distance between them and directly proportional to the product of the charges.


To understand this concept, consider two electrically charged particles that are close to each other. An attraction or repulsion force will act on the particles depending on the nature of their charge (positive or negative). This force between two electrically charged bodies can be calculated using Coulomb's Law, which was developed by Charles-Augustin de Coulomb. 

Coulomb's Law Formula

Let Q1 and Q2 represent the charges of the two electrically charged entities, and 'd' represents the distance between their centres. If the electrically charged bodies are put in a permittivity medium, the force can be described as:

F = k ((Q1/Q2)/d2)


Q1, Q2 = charges

f = electric force

k = Coulomb constant

r = distance of separation

Electric field

Electric field lines make the electric field easier to see. Field lines have a positive charge at the beginning and a negative charge at the end. Electric field lines run parallel to its direction, and their density serves as a gauge for the strength of the electric field at any particular point.

The smallest unit charge is 1.6021 x 10-19 Coulomb (C), and we denote charge with the letter "q" or "Q". A proton and an electron both have one charge.

Positively Charged Particles

The positive ions are more prevalent in these particles than the negative ones. This indicates that there are more protons than electrons in the universe. When a positively charged particle needs to be neutralized, nearby electrons approach it until the ratio of protons to electrons is equal.

Negatively Charged Particles

Similar to protons, there are more electrons than there are. Since protons are immobile and unable to interact with negatively charged particles, electrons must move to the surrounding particles or the ground in order to neutralise negatively charged particles.

Neutral Particles

Protons and electrons are present in an equal proportion in neutral particles. They contain protons, neutrons, and electrons, but the proportion of positive to negative ions is equal.

Electrostatics Examples

There are countless examples of electrostatic phenomena:

The attraction of plastic wrap to your hand after removing it from a package.

Paper's attraction to a charged scale.

Grain silos appear to have exploded spontaneously.

Electronic component failure during manufacturing.

Use of a photocopier with a laser printer.