Coulomb's law is an equation describing the electrostatic force on a charged particle due to the presence of other charges. It was developed in the 1780s by French physicist Charles Augustin de Coulomb and was fundamental to the development of the theory of electromagnetism. Coulomb's law states that the magnitude of the electrostatic force between two point electric charges is directly proportional to the product of the magnitudes of each of the charges and inversely proportional to the square of the total distance between the two charges, and in the direction of the vector connecting the two charges. The proportionality constant is 8.988x10^4 N(m/C)^2. Newtons third law is satisfied since the force of one charge on the other is equal for both charges.

In equation form,

F = k q1 q2/r^2 = (1/4PIeo) q1 q2 / r^2

In honor of his experiments defining this law, the unit of charge is known as the Coulomb. 1 Coulomb is an enormous amount of charge. If two charged bodies each with 1 C of charge were placed 1 meter apart, the force between them would be 1 million tons!