An uncharged metal sphere is placed on an insulating puck on a frictionless table. While being held parallel to the table, a rod with a charge q is brought close to the sphere, but does not touch it. As the rod is brought in, the sphere
A) remains at rest.
B) moves toward the rod.
C) moves away from the rod.
D) moves perpendicular to the velocity vector of the rod.
E) moves upward off the puck.

Question

Quizplus · Accepted Answer

When the charged rod is brought near the uncharged metal sphere, the electrons within the sphere will be repelled by the like charge on the rod, causing them to move away from the rod and toward the opposite side of the sphere. This creates an induced charge separation in the sphere, leaving the side closest to the rod with a net positive charge and the opposite side with a net negative charge. This results in an attractive force between the rod and the sphere, causing the sphere to move toward the rod.

An Uncharged Metal Sphere Is Placed on an Insulating Puck