In a charging process, 5 × 1013 electrons are removed from one metal sphere and placed on a second sphere. Then the electrical poten- tial energy associated with the two spheres is found to be -0.072 J. Initially, both metal spheres are neutral.
The value of the Coulomb constant is 8.98755 × 109 N · m2/C2 and the charge on an electron is 1.6 × 10-19 C .
What is the distance between the two spheres?
Answer in units of m.