Short Answer:

Coulomb’s law states that the force between two electric charges depends on the size of the charges and the distance between them. The force increases when the charges are large and decreases when the distance between them increases.

This force acts along the line joining the two charges. If the charges are of the same type, they repel each other, and if they are of different types, they attract each other.

Detailed Explanation:

Coulomb’s law

Coulomb’s law explains the force of attraction or repulsion between two electric charges. It is one of the most important laws in electrostatics. According to this law, 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. This means that if the charges increase, the force also increases. Similarly, if the distance between the charges increases, the force becomes weaker.

Mathematically, Coulomb’s law is written as:

F = k × (q₁ × q₂) / r²

Here,
F is the force between the charges,
q₁ and q₂ are the magnitudes of the charges,
r is the distance between the charges,
k is a constant (called Coulomb’s constant).

The value of k depends on the medium between the charges. In vacuum or air, its value is approximately 9 × 10⁹ N·m²/C².

This law shows that electric force is very sensitive to distance. For example, if the distance is doubled, the force becomes one-fourth. This is because of the inverse square relation.

Nature of force

The force described by Coulomb’s law can be either attractive or repulsive. This depends on the type of charges involved.

If both charges are positive or both are negative, the force is repulsive. This means the charges push each other away. On the other hand, if one charge is positive and the other is negative, the force is attractive. In this case, the charges pull each other closer.

The force always acts along the straight line joining the two charges. This is called a central force. It does not depend on the direction of motion but only on the position of the charges.

Another important point is that Coulomb’s law applies only to point charges or charges that are very small compared to the distance between them. For larger bodies, the law is applied by considering them as collections of small charges.

The medium between the charges also affects the force. In materials other than air or vacuum, the force is reduced due to the presence of a dielectric medium. This is why the value of k changes in different materials.

Coulomb’s law is similar to Newton’s law of gravitation in form, but the forces are different in nature. Gravitational force is always attractive, while electric force can be both attractive and repulsive.

Conclusion:

Coulomb’s law is a basic law of electrostatics that describes how electric charges interact with each other. It shows that force depends on charge and distance. This law is very useful in understanding electric fields, circuits, and many electronic devices.