Question

- Two small silver spheres each with a mass of 100gm are separated by 1 m. Calculate the number of electrons that must be transferred from one to the other to produce an attractive force of 104 N between the spheres.

Answer 1

Apply Coulomb's law:

$$F=\frac1{4\pi\epsilon_0}\frac{(ne)^2}{r^2},\\\space\\ n=\frac {2r}e\sqrt{\pi\epsilon_0F}=6.58·10^{15}$$

assuming the force is 10⁴ N, not 104 N.