A student is investigating what happens when a neutral metal sphere sitting on an insulated stand is touched by a negatively charged rod. The set up for the student's investigation is shown in the diagram.

Question

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What will happen to the excess electrons when the negatively charged rod touches the metal sphere?

a
The excess electrons will move from the sphere to the rod and stay clustered near the end of the rod that touches the sphere.
b
The excess electrons will move from the rod to the sphere and spread out on the sphere.
c
The excess electrons will move from the rod to the sphere and stay clustered in the area where the rod touches the sphere.
d
The excess electrons will move from the sphere to the rod and spread out along the rod.

Answer 1

When a negatively charged rod touches a neutral metal sphere, the interaction leads to a transfer of charge. Since the rod has excess electrons, these electrons will move to the sphere because the sphere is neutral and the contact allows for the flow of charge.

Once the electrons move from the rod to the sphere, they will spread out evenly across the surface of the conductor (the metal sphere) due to the repulsive forces between the like charges.

Therefore, the correct answer is:

b. The excess electrons will move from the rod to the sphere and spread out on the sphere.