Question

A force of 230N exist between two identical point charges of 56uC. Calculate the distance of the two point charge.

Answer 1

$$F=k\frac{q_1q_2}{r^2 }$$

$$r=\sqrt{kq^2/F}\\ =\sqrt{9*10^9*(56*10^{-6})^2/230}=0.35\:\rm m$$