Why do like charges repel and unlike charges attract?

Like charges repel and unlike charges attract due to the electromagnetic force, one of the four fundamental forces of nature.

The concept of charges and their interactions is a fundamental aspect of physics. It is governed by the electromagnetic force, which is one of the four basic forces in the universe, alongside gravity, the strong nuclear force, and the weak nuclear force. This force is described by Coulomb's Law, which states that the force between two charges is directly proportional to the product of their charges and inversely proportional to the square of the distance between them.

Charges are either positive or negative. When two charges are the same, they are referred to as 'like charges'. When they are different, they are 'unlike charges'. According to the principles of electromagnetism, like charges repel each other, while unlike charges attract each other. This is because the electromagnetic force between like charges is outward, pushing them apart, while the force between unlike charges is inward, pulling them together.

This principle is observable in many everyday phenomena. For instance, when you rub a balloon against your hair, it becomes negatively charged by gaining electrons. If you then bring the balloon near your hair, the negatively charged balloon and the negatively charged hair repel each other, causing your hair to stand on end. Conversely, if you bring the negatively charged balloon near a positively charged object, they will attract each other.

In essence, the interaction between charges is a fundamental aspect of the physical world, governing everything from the structure of atoms to the behaviour of electricity. Understanding why like charges repel and unlike charges attract is key to understanding many aspects of physics.