The respective radii of the two spheres of a spherical condenser are `12 cm` and `9 cm`. The dielectric constant of the medium between them is `6`. The capacity of the condenser will be

Options

A. `240 pF`
B. `240 mF`
C. `240 F`
D. None of the above

Answer

A

Explanation

`C = 4pi epsilon_(0)K [(ab)/(b - a)] = (1)/(9 xx 10^(9)).6 [(12 xx 9 xx 10^(-4))/(3 xx 10^(-2))]`
`= 24 xx 10^(-11) = 240 pF`