Question

In (Fig. 3.73), if the inner shell has charge `+q_0` and the outer shell is earthed, then
.
i. determine the charge on the outer shell, and
ii. find the potential of the inner shell.

Answer 1

We know that charge on facing surfaces is equal and opposite,So if charge on inner sphere is `q_(0)` then charge on inner surface of shell should be `-q_(2)`,As the shell is earthed.So its potential should be zero So,

`V_("Shell")=(kq_(0))/(r_(2))+(k(-q_(0)))/(r_(2))+(kq_(2))/(r_(2))=0rArrq_(2)=0`
Here,charge on outer surface of shell is zero.Final charges appearing are shown in fig.
(b) Potenital of inner sphere:
`V_(1)=(kq_(0))/(r_(2))+(k(-q_(0)))/(r_(2))=(q_(0))/(4piepsilon_(0))[(1)/(r_(1))-(1)/(r_(2))]`