Coulomb’s law l Explanation Statement Formulas Principle...

Coulomb’s law

The force between two charged bodies was studied by Coulomb in 1785.
Coulomb’s law states that the force of attraction or repulsion between two point charges is directly proportional to the product of the charges and inversely proportional to the square of the distance between them. The direction of forces is along the line joining the two point charges.
Let q1 and q2 be two point charges placed in air or vacuum at a distance "d" apart Then, according to Coulomb’s law,

Where,

1. ‘F’ is the repulsion or attraction force between two charged bodies.
2. ‘Q₁’ and ‘Q₂’ are the electrical charged of the bodies.
3. ‘d’ is distance between the two charged particles.
4. ‘k’ is a constant that depends on the medium in which charged bodies are presented. In S.I. system, as well as M.K.S.A. system k=1/4πε. Hence, the above equation becomes.

The value of ε₀ = 8.854 × 10^-12 C²/Nm².
Hence, Coulomb’s law can be written for medium as,

  
Then, in air or vacuum εr = 1. Hence, Coulomb’s law can be written for air medium as,

 

Limitation of Coulomb’s Law

1. Coulomb’s law is valid, if the average number of solvent molecules between the two interesting charge particles should be large.
2. Coulomb’s law is valid, if the point charges are at rest.
3. It is difficult to apply the Coulomb’s law when the charges are in arbitrary shape. Hence, we cannot determine the value of distance ‘d’ between the charges when they are in arbitrary shape.

Created By Manjeet Singh...