How many excess electrons must be present on each sphere if the magnitude of the force of repulsion between them is 4.57×10−214.57×10−21 newtons?

There are 887.5 number of excess electrons on the each spheres.

Explanation:

It is given that, the force of repulsion between two spheres is,

We know that the force of attraction or repulsion between charges is given by :

It is assumed that the separation between the spheres is 20 cm or 0.2 m. So,

Let there are n excess electrons that must be present on each sphere. It can be given by using quantization of charge as :

n = 887.5 electrons

So, there are 887.5 number of excess electrons on the each spheres. Hence, this is the required solution.