Question

In Figure 18.8 the grounding wire is removed first, followed by the rod, and the sphere is left with a positive charge. If the rod were removed first, followed by the grounding wire, would the sphere be left with a charge? Account for your answer.

Answer 1

In Figure 18.9, the ground wire is first removed, then the rod. This leaves a positive charge on the sphere. If you remove the rod first and then remove the ground wire, there will be no charge left on the sphere. When the rod is removed, the repulsive force caused by the presence of the rubber rod no longer exists. As the wire is still attached, free electrons enter the sphere from the ground until the sphere is neutral again.