Fields Of Force. Newton’s universal gravitational law and Coulomb’s law enable us to calculate the magnitude as well as directions of the gravitational and electric forces.

Now, two questions arise,

1. What are the origins of these forces?
2. How are these forces transmitted from one mass to another or from one charge to another?

The answer to the first question is still unknown as the existence of these forces is accepted as it is.

That is why they are called the basic forces of nature.

To describe the answer to the second question, Micheal Faraday introduced the concept of an electric field.

According to this theory, an electric field exists around an electric charge.

This electric field is considered to be a force field that exerts a force on the other charges as they enter the field.

For example, a charge q produces an electric field around itself and this field exists whether or not any other charges interfere with the space.

But if any other charges do not interfere with the field, the force can not be tested.

Thus, the charge q     is bought into the field and the field exerts a force on the charge q.

The electric field intensity can be expressed as 

E=Fq 

F is the force experienced by the charge qand the test charge must be very small so it does not distort the field.