question_answer

A small conducting sphere of radius\[a\], carrying a charge\[+Q\], is placed inside an equal and oppositely charged conducting shell of radius b such that their centers coincide. Determine the potential at a point which is at a distance c from center such that a < c < b.

A) \[k(Q/c+Q/b)\]

B) \[k(Q/a+Q/b)\]

C) \[k(Q/a-Q/b)\]

D) \[k(Q/c-Q/b)\]

Correct Answer: D

Solution :

[d] \[V=\frac{kQ}{c}-\frac{kQ}{b}=k\left( \frac{Q}{c}-\frac{Q}{b} \right)\]