Question

Calculate the force between charges 4x10^-8 C and 1.8x10^-6 C if they are 3.5 m apart

Answer 1

The force between these charges can be calculated by Coulomb's law:

$$F=\frac{1}{4\pi\epsilon_0}\frac{q_1q_2}{R^2},\\\space\\ F=\frac{1}{4(3.14)(8.85·10^{-12})}\frac{(4·10^{-8})·(1.8·10^{-6})}{3.5^2}=5.28·10^{-5}\text{ N}.$$