electric charge
Electromagnetism is associated with charge and is a fundamental force of nature, like gravity. If charges are static, the only manifestation of electromagnetism is the Coulomb electric force. In the same way that gravitational force depends on mass, the Coulomb electric force depends on the property known as electric charge. Like gravity, the Coulomb electric Force decreases with the square of the distance. The Coulomb electric force is responsible for many of the forces we discussed previously: the normal force, contact forces such as friction, and so on - all of these forces arise in the mutual attraction and repulsion of charged particles.