"Electric Charge" is a fundamental conserved property of some subatomic particles, which determines their electromagnetic interaction. Electrically charged matter is influenced by, and produces, electromagnetic fields. The electric charge on a body may be positive or negative. Two positively charged bodies experience a mutual repulsive force, as do two negatively charged bodies. A positively charged body and a negatively charged body experience an attractive force. Electric charge is carried by discrete particles and can be positive or negative. The sign convention is such that the elementary electric charge \(e\), that is, the charge of the proton, is positive. The SI derived unit of electric charge is the coulomb.