Question

Three concentric spherical conducting shells A, B and C of radii a, 2a and 4a are initially given charges +Q, -2Q and +Q respectively. The charge on the middle spherical shell B after switches `S_(1)` and `S_(2)` are simultaneously closed, will be
A. `-Q`
B. `-(Q)/(2)`
C. `+Q`
D. `(+3Q)/(2)`

Answer 1

Correct Answer - B

The electric potential potential of shell B is zero
`V_(B)=0`
`(kq)/(2a)+(kQ)/(4a)=0`
`thereforeq=-(Q)/(2)`