If the circumference of a sphere is 2 m, then capacitance of sphere in water would be

Options

A. `2700 pF`
B. 2760 pF
C. 2780 pF
D. 2830 pF

Answer

D

Explanation

For the sphere`=2pir=2m`
`therefore r=(1)/(pi)m andK_("water")=80`
`therefore`Capacitance of the sphere
`=(4piepsi_(0)r)K`
`=(1)/(9xx10^(9))xx(1)/(pi)xx80=(8)/(9xx3.14)xx10^(-8)F`
`=(8)/(9xx3.14)xx10^(4)pF" "(because 1F=10^(+12)pF)`
`therefore C=0.2830xxx10^(4)=2830pF`