Question

The capacitance of a metallic sphere is $1\mu F$, then it's radius is nearly

• A. 1.11 m
• B. 10 m
• C. 9 km
• D. 1.11 cm

Answer 1

Answer: (C)

9 km

The capacitance of a sphere of radius $R$ is $C=4\pi {ϵ}_{0}R$
$\Rightarrow R=\frac{1}{4\pi {ϵ}_0}\times C=9\times {10}^9\times {10}^{-6}=9000m=9km$