Two point charges of magnitude 30 x 109 C and 60 x 109 C arc

Two point charges of magnitude 3.0 x 10^-9 C and 6.0 x 10^-9 C arc separated by a distance of 0.30 m. Find the electric force of repulsion between them.

Solution

Force of repulsion = KQ₁Q₂/(distance)²

K=9x10⁹ Nm²/C², Q₁=3.0x10^-9 C_, Q₂=6.0x10^-9 C, distance=0.30m

Force of repulsion = 9x10⁹ x 3.0x10^-9 x 6.0x10^-9 / (0.30)² =18 x 10^-7 N