There is a hollow,conducting,uncharged sphere with a negative charge inside the sphere.Consider the electrical potential at the inner and outer surfaces of the sphere.Which of the following is true?
A)The potential on the inner surface is greater.
B)The potential on the outer surface is greater.
C)The potentials on both surfaces are zero.
D)The potentials on both surfaces are equal but not zero.

Question

There is a hollow,conducting,uncharged sphere with a negative charge inside the sphere.Consider the electrical potential at the inner and outer surfaces of the sphere.Which of the following is true? 
A)The potential on the inner surface is greater. 
B)The potential on the outer surface is greater. 
C)The potentials on both surfaces are zero. 
D)The potentials on both surfaces are equal but not zero.

Quizplus · Accepted Answer

Since the sphere is uncharged, the total charge inside the sphere must be zero. However, we know there is a negative charge inside the sphere, so there must be an equal and opposite positive charge distributed on the inner surface of the sphere, which cancels out the negative charge. Thus, the potential at the inner surface is equal in magnitude but opposite in sign to the potential due to the negative charge inside the sphere. Similarly, the potential at the outer surface of the sphere is equal in magnitude but opposite in sign to the potential due to the negative charge inside the sphere. Since the potential due to the negative charge inside the sphere is the same at both surfaces, the potentials at the inner and outer surfaces must be equal but not zero. Therefore, choice D is correct.

There Is a Hollow,conducting,uncharged Sphere with a Negative Charge Inside