Consider three identical metal spheres, A, B, and C. Sphere A carries a charge of +4q. Sphere B carries a charge of -7q. Sphere C carries no net charge. Spheres A and B are touched together and then separated. Sphere C is then touched to sphere A and separated from it. Lastly, sphere C is touched to sphere B and separated from it.
(a) How much charge ends up on sphere C?
(b) What is the total charge on the three spheres before they are allowed to touch each other?
(c) What is the total charge on the three spheres after they have touched?