Question

If the maximum circumference of a sphere is 2 m, then its capacitance in water would be :-
(Dielectric constant of water = 81)

• A. 2385 pF
• B. 2865 pF
• C. 27.65 pF
• D. 236.5 pF

Answer 1

Answer: (B)

Given,

${\epsilon }_0=8.85\times {10}^{-12}$

${\epsilon }_r=81$

Perimeter, $L=2\pi r=2m$

$r=\frac{1}{\pi }$

The capacitance in water,

$C=4\pi {\epsilon }_0{\epsilon }_{r}r$

$C=4\pi \times 8.85\times {10}^{-12}\times 81\times \frac{1}{\pi }$

$C=2865pF$

The correct option is D.