Question

Find the distance between the two charges, q₁ with 36 nC and q₂ with 22 nC. The electric potential energy is 9.912 x 11^-3 N x m

Answer 1

$$E_p=k\frac{q_1q_2}{r}$$

$$r=k\frac{q_1q_2}{E_p}\\ =9*10^9*\frac{36*10^{-9}*22*10^{-9}}{9.912*10^{-3}}=7.2*10^{-4}\:\rm m$$