Question

what is coulombs law and its application

Answer 1

Coulomb - Coulomb's Law
Coulomb's law applies whether the two bodies in question have similar or opposite charges. The only difference is one of sign. If a positive value of F is taken as a force of attraction, then a negative value of F must be a force of repulsion. …

Coulomb - Applications
Coulomb's law is absolutely fundamental, of course, to any student of electrical phenomena in physics. However, it is just as important in understanding and interpreting many kinds of chemical phenomena. For example, an atom is, in one respect, nothing other than a collection of electrical charges, positively charged protons, and negatively charged electrons.

Answer 2

force acting between two charged bodies is directly proportional to product of the charges and inversely proportional to square of the distance of separation