Question

An isolated hollow metal sphere is electrically neutral (no excess charge) and supported on an insulating stand. A small amount of negative charge is suddenly placed at one point P on this metal sphere. If we check on this excess negative charge a few seconds later we will find one of the following possibilities :

• A. All of the excess charge remains right around P.
• B. The excess charge has distributed it self evenly over the outside surface of the sphere.
• C. The excess charge is evenly distributed over the inside and outside surface.
• D. Most of the charge is still at point P, but some will have spread over the sphere.

Answer 1

The correct option is B The excess charge has distributed it self evenly over the outside surface of the sphere.

In the case the negative charge that started on point P will be distributed evenly throughout the surface of the sphere since that point P has too much negative charges in it, so the negatively charged atoms will repel each other more vigorously until they move to a place (i.e. a place NOT on point P ) where there's less negatively charged atoms. But, also note that point P will still be negatively charged just like the rest of the sphere, but now all of the sphere's surface will have the same amount of charges.