Step-by-step explanation:
Force between two point changes, F₁ = 1 N
Distance between them, r₁ = 2 cm = 0.02 m
We know that the electrostatic force is given by :

i.e.

i.e

Let F₂ is the force when the distance between the charges is 8 cm, r₂ = 0.08 m


F₂ = 0.0625 N
So, the distance between the sphere is 8 N, the new force is equal to 0.0625 N. Hence, this is the required solution.