Answer to Question #84443 in Electricity and Magnetism for cyril

Question

A point charge q1 is held stationary at the origin. A second charge q2 is placed at point a, and the electric potential energy of the pair of charges is 5.4 x 10^-8J. When the second charge is moved to point b, the electric force on the charge does -1.9x10^-8J of work. What is the electric potential energy of the pair of charges when the second charge is at point b?

Answer 1

U=U_0-A=5.4∙〖10〗^(-8)+1.9∙〖10〗^(-8)=7.3∙〖10〗^(-8) J