Question

obtain an expression for the intensity of an electric field at a point due to point charge

Answer 1

Answer:

Consider a point charge q called SOURCE CHARGE placed at a point ‘O’ in space. To find its intensity at a point ‘p’ at a distance ‘r’ from the point charge we place a test charge 'q'.

The force experienced by the test charge q’ will be:

F = Eq’----(1)

According to coulomb's law the electrostatic force between them is given by:

Putting the value of 'F' we get : www.citycollegiate.com

This shows that the electric intensity due to a point charge is directly proportional to the magnitude of charge q and inversely proportional to the square of distance.

EFFECT OF DIELECTRIC MEDIUM

If there is a medium of dielectric constant (er) between the source charge and the field charge,intensity at a point will decrease er times i.e.