A system consisting of one positively charged particle and one negatively charged particle is altered by an outside force so that its potential energy increases by 6.25 mJ. There is no change in kinetic energy between the initial and final states of the system.
(a) What is the work done by the outside force?
(b) What is the work done by the electric force?
(c) Are the particles closer together or farther apart after the system's rearrangement?