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?

Answer 1

Here , when A and B are touced

charges on them will become equal

qA = qB = (-10q + 9q)/2

qA = qB = - 0.50 q

when C and A are touched

qA = qC = -(0.50q)/2

qA = qC = -0.25q

Now, when C and B is touched

qC = qB = -(0.25q + 0.50q)/2

qC = qB = -0.375q

a) the final charge on sphere C is - 0.375q

b) total charge before touching = -10q + 9 q

total charge before touching = -q

c)

total charge after touching = - 0.375q - 0.375q - 0.25q

total charge after touching = - q