Question

Two charges (−12.6 × 10−12 𝐶𝐶 and − 1.13 × 10−13 𝐶𝐶) are separated by a distance of

3.75 𝜇𝜇𝑚𝑚. Compute the force of attraction between them.

Answer 1

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

$$F=9*10^9\frac{\rm N\cdot m^2}{\rm C^2}*\frac{12.6*10^{-12}\: \rm C*1.13*10^{-13}\: C}{(3.75*10^{-6}\:\rm m)^2}\\ =9.11*10^{-4}\:\rm N$$