Consider three identical metal spheres, A, B, and C. Sphere A carries a charge o
ID: 2000068 • Letter: C
Question
Consider three identical metal spheres, A, B, and C. Sphere A carries a charge of -10q. 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. Last, sphere C is touched to sphere B and separated from it. For the following questions, express your answers in terms of q. (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?
Explanation / Answer
Charges on each sphere A & B after they are touched together = (-10q + 9q)/2 = -0.5q
Charges on each sphere A & C after they are touched together = (-0.5q + 0)/2 = -0.25q
Charges on each sphere B & C after they are touched together = (-0.5q + -0.25q)/2 = -0.375q
(a) So spehere C ends up with charge= -0.375q
(b)Total charge on three spehere before they touch = -q
(c)Total charge on thee sphere will remain same : (-0.25q) + (-0.375q) + (-0.375q) = -q