A spherical capacitor has the inner sphere of radius `2 cm` and the outerone of `4 cm`. If the inner sphere is earthed and the outer one is charged with a charge of `2muC` and isolated. Calculate ltbr. (a) the potential to which the outer sphere is raised.
(b) the charge retained on the outer surface of the outer sphere.

Answer

A, C

Explanation

a. Let `q` be the charge on smaller sphere. Then
`V_("inner")=0`
`:. (Kq)/2+(K(2))/4=0` or `q=-1muC`
Now, `V_(outer)=(K(2-1)xx10^-6)/(4xx10^-2)`
`(9xx10^9xx10^-6)/(4xx10^-2)`
`=2.25xx10^5V`
b. charge distribution is as shown in above figure.