Two equally charged identical metal spheres A and B repel each other with a force of 2 ×10-5 N. Another uncharged identical sphere C is touched to B and then placed in a mid point between A and B. What is the net electric force on C?

2 × 10-5   zero 4 × 10-5  6 ×  10-5

6 ×  10-5

F = kq2/r2 = 2 × 10-5 N Force on c : F' = k(q)(q/2)/[r/2]2 + k(q/2)(q/2)/[r/2]2 F' = 3 \(\frac{kq^{2}}{r^{2}}\) = 3 x 2 × 10-5 N = 6 ×  10-5 N