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 stay clustered in the area where the rod touches the sphere.
c
The excess electrons will move from the rod to the sphere and spread out on 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 excess electrons from the rod will move to the sphere due to the difference in electric potential. This will happen because the metal sphere is neutral, and it allows electrons to move until equilibrium is reached.

Once contact is made, the excess electrons will move from the negatively charged rod to the neutral metal sphere and will then spread out over the surface of the sphere. This occurs due to the conductive nature of the metal, which allows electrons to distribute evenly to minimize repulsion between them and achieve a uniform charge distribution.

Therefore, the correct answer is:

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