Q 1.2: The electrostatic force on a small sphere of charge due to another small sphere of charge in air is .(b)What is the force on the second sphere due to the first?
Using Newton's third law, the force exerted by the spheres on each other will be equal in magnitude.
Therefore, Force on second sphere due to the first = 0.2 N (This force will be attractive, since charges are of opposite sign.)