Two identical conducting spheres, A and B, carry equal charge. They are separated by a distance much larger than their diameters. A third identical conducting sphere, C, is uncharged. Sphere C is first touched to A, then to B, and finally removed.
1. As a result, the electrostatic force between A and B, which was originally F, becomes :A. F/2B. F/4C. 3F/8D. F/16E. 0

C.

Explanation:

Let initial charges on both spheres be,

When the sphere C is touched by A, the final charges on both will be,

#Now, when C is touched by B, the final charges on both of them will be:

Now the force between A and B is calculated as:

Hence the electrostatic force becomes 3F/8

the answer is to check all of them! they all apply well at least i think so!

seeing the graph would