Consider three identical metal spheres, A, B, and C. Sphere A carries a charge of +4q. Sphere B carries a charge of -9q. 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?
________q
(b) What is the total charge on the three spheres before they are allowed to touch each other?
________q
(c) What is the total charge on the three spheres after they have touched?
________q