There are 2 point charges. q1 is 4nc and is at (-2,0). q2 is -2nc and is at (0,3).
how much work does the electric field do when a third point charge of +3.00 nc is moved from infinitely far away and placed at the origin?
i know infinitely far means va will be 0. however because there are 2 other charges instead of 1, i do not know how to manipulate k(q)/d to fit all the charges in.

An electron is trapped at a defect in a crystal. the defect may be modeled as a one-dimensional, rigid-walled box of width 1.00 nm. (a) sketch the wavefunctions and probability densities for the n 1 and n 2 states. (b) for the n 1 state, nd the probability of nding the electron between x1 0.15 nm and x2 0.35 nm, where x 0 is the left side of the box. (c) repeat (b) for the n 2 state. (d) calculate the energies in electron volts of the n 1 and n 2 states