A and B are two concentric spherical shells. If A is given a charge `+q` while B is earthed as shown in figure then

Options

A. charge on the outer surface of shell B is zero
B. the charge on B is equal and opposite to that of A
C. the field inside A and outside B is zero
D. All of the above

Answer

D

Explanation

`V_B=0`
`:. (k_(q_A))/r_B+(k_(q_B))/r_B=0`
`:. q_B=-q_A=-q`
Charge distribution is as shown below.
From Gauss's theorem electric field at any point is given by
`E=(kq_("in"))/r^2`
`q_("in")` inside A outside B is zero. Therefore `E=0`