Physics 1028 Study Guide - Final Guide: Centripetal Force, Electric Potential Energy, Electric Potential
Document Summary
[18. 8] gives the potential for a point charge: Solution to part (b): the electric potential energy follows from the charge and the potential: (1) (2) in which the negative sign is due to the opposite signs of the two interacting charges. This means that the electron is attracted by the proton. Solution to part (c): as the electron comes closer to the proton the electric potential energy becomes even more negative than calculated in eq. Following the hint, we built the system of charges by moving one after the other from a place where they are all at infinite distance to each other. Since the electric force decreases rapidly with distance, a distance equivalent to an infinite distance might practically be a rather short distance. In vacuum this distance is quite large for a precise measurement; however, in a solution a few micrometres is an infinite distance due to charge screening effects.
