When workWABis done by an electricforceas a posi-tive test charge+q0moves from point Ato point B, the work equals the electric potential energyEPE at Aminus that at B: WAB= EPEA- EPEB. The electric potential Vis the electric potential energyper unitcharge, V= EPE/q0. The electric potentialdifference between two points is VB- VA= (EPEB- EPEA)/q0= -WAB/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 rfrom a point charge qis V = kq/r. This expression for Vassumes the potential is zero at an infinite distance away from the charge.The electron volt(eV) is a unitof energy. One electron volt corresponds to 1.60×10-19 J and is the amount by which the potential energyof an electron changes when the electron moves through a potential difference of one volt.
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