Concept #1: Conservation of Charge

Consider three identical metal spheres, A, B, and C. Sphere A has a charge of -2μC; sphere B has a charge of -6μC; and sphere C has a charge of +4μC. Spheres A and B are touched together and then separated. Spheres B and C are then touched and separated. Does sphere C end up with an excess or a deficiency of electrons and how many electrons is it?
A) deficiency, 6x1013
B) excess, 3x1013
C) excess, 2x1013
D) deficiency, 3x1012
E) There is no imbalance of electrons.

Two uncharged, conducting spheres, A and B, are held at rest on insulating stands and are in contact. A positively charged rod is brought near sphere A. While the rod is in place, someone moves sphere B away from A. How will the spheres be charged, if at all?
A) A+ and B+
B) A- and B-
C) A+ and B-
D) A- and B+
E) A=0 and B=0

Consider three identical conducting spheres in an equilateral triangle, two with a 4 C charge and one with a -4 C charge. If the spheres are all connected by a thin wire, what is the final charge on the lower left-hand sphere?
A) 0.333333
B) 3.66667
C) 1.33333
D) 2.0