The force between two charged objects depends on how close they are to each other. If the charges are of the same type, the force is repulsive. If the charges are different types then the force is attractive.In 1784, Charles Coulomb devised a very sensitive torsion balance to measure the force between two charged pith balls.
He discovered that halving the distance quadrupled the force and doubling the charges on either ball doubled the force.
He discovered that halving the distance quadrupled the force and doubling the charges on either ball doubled the force.