where F is the force, k e is the Coulomb constant, q 1 and q 2 are the magnitudes of the two charges, and r is the square of the distance between them. It describes the fact that like charges repel one another whereas opposite charges attract one another and that the stronger the charges of the particles, the stronger the force they exert on one another. The law is also an inverse square law which means that as the distance between two particles is doubled, the force on them is reduced by a factor of four.