Two spheres are made of conducting material. Sphere #2 has twice the radius of Sphere #1. What is the ratio of the capacitance of Sphere #2 to the capacitance of sphere #1?
A) 1, since all conducting spheres have the same capacitance.
B) 2
C) 4
D) 8
E) A single sphere has no capacitance since a second concentric spherical shell is necessary to make a spherical capacitor. Thus, none of the answers above is correct.

Question

Quizplus · Accepted Answer

The capacitance of a conducting sphere is given by $C = 4\pi\epsilon_0 r$, where $r$ is the radius of the sphere. If Sphere #2 has twice the radius of Sphere #1, its capacitance is twice as much, since capacitance is directly proportional to the radius.

Two Spheres Are Made of Conducting Material