A spherical conductor of radius `2 m` is charged to a potential of `120 V`. It is now placed inside another hollow spherical conductor of radius `6 m`. Calculate the potential to which the bigger sphere would be raised

Options

A. `20 V`
B. `60 V`
C. `80 V`
D. `40 V`

Answer

D

Explanation

If charge acquired by the smaller sphere is `Q` then its
potential `120 = (kQ)/(2)` ..(i)
Also potential of the outer sphere
`V = (kQ)/(6)` ..(ii)
From equations (i) and (ii) `V = 40` volts