Two uncharged, conducting spheres are separated by a distance d. When charge - Q is moved from sphere A to sphere B, the Coulomb force between them has magnitude F0.

(a) Is the Coulomb force attractive or repulsive?

attractive repulsive

(b) If an additional charge - Q is moved from A to B, what is the ratio of the new Coulomb force to the original Coulomb force, (c) If sphere B is neutralized so it has no net charge, what is the ratio of the new to the original Coulomb force,

Answer: a) the force will be repulsive

b) the ratio of the new force to the old force will be 2

c) O

Explanation:

a) since charge - Q is moved from A to B, this implies that sphere A is negatively charged. The two spheres are now negatively charged and will repel themselves.

b) initial force will be - q (-Q) / d2

Adding extra charge - Q will cause change on B to become - 2Q

The new force will be - 2Q (-q) / d2

Dividing new force by old force will give 2

C) if B is neutralized, the net charge becomes 0 and there will be no force on it.