When work W AB is done by an electric force as a posi-tive test charge + q0 moves from point A to point B , the work equals the electric potential energy EPE at A minus that at B : W AB = EPE A- EPE B . The electric potential V is the electric potential energy per unit charge, V = EPE/ q0 . The electric potential difference between two points is V B- V A = (EPE B- EPE A )/ q0 = -W AB / q0 . A positive charge accelerates from a region of higher potential toward a region of lower potential. Conversely, a negative charge accelerates from a region of lower potential toward a region of higher potential. The electric potential at a distance r from a point charge q is V = kq / r . This expression for V assumes the potential is zero at an infinite distance away from the charge. The electron volt (eV) is a unit of energy. One electron volt corresponds to 1.60×10-19 J and is the amount by which the potential energy of an electron changes when the electron moves through a potential difference of one volt. An
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This note was uploaded on 04/09/2008 for the course PHYS 101 taught by Professor Sharp during the Spring '08 term at Ohio State.