Question

a) Two identical charges q₁ and q₂ make up a system with a potential energy of 1590J when the distance between them is 0.4m. Find the magnitude of the charges q₁ and q₂.

Answer 1

$$U=k\frac{q^2}{r}\\1590=9\cdot10^{9}\frac{q^2}{0.4}\\q=2.66\cdot10^{-4}\ C$$