Question

when the distance between two charged particles is made one third the force between them becomes.......

Answer 1

Assuming that you're talking about point charges, according to Coulomb's Law, F=kQq/r2F=kQq/r2
the fore is directly proportional to the product of the two charges and inversely proportional to the distance between them. Because of this, if the distance increased by two, then the force will increase by 1/22=1/41/22=1/4, thus the force decrease to 1/4 of the original value :)

Answer 2

Coulomb's law, or Coulomb's inverse-square law, is a law of physics that describes force interacting between static electrically charged particles. In its scalar form, the law is: F = k e q