Question

A sphere of `4 cm` radius is suspended within a hollow sphere of `6 cm` radius. The inner sphere is charged to potential `3` e.s.u. and the outer sphere is earthed. The charge on the inner sphere is
A. `54 e.s.u.`
B. `(1)/(4)e.s.u.`
C. `30 e.s.u.`
D. `36 e.s.u.`

Answer 1

Correct Answer - D
Suppose charge on inner sphere is `+Q` as shown.
Potential on inner sphere
`V = (Q)/(4) - (Q)/(6)`
`rArr 3 = Q ((1)/(4)-(1)/(6)) rArr Q = 36 e.s.u`