1. The problem statement, all variables and given/known data There are 2 small metal balls of radius r1 and r2 and are kept at very large distance , what should be ratio of charges on them for electrostatic energy to be minimum 2. Relevant equations E=Q^2/(8πϵR) Self Energy 3. The attempt at a solution In this problem, electric potential must be zero since the balls are at a very large distance from each other, so I was considering the self energy of metallic spheres which is E . How to find the charge ratio for minimum electrostatic energy?