Question

The respective radii of the two spheres of a spherical condenser are $12 ⥂ \mspace{6mu} cm$ and$9\mspace{6mu} cm$. The dielectric constant of the medium between them is 6. The capacity of the condenser will be

• A. $240pF$
• B. $240\mu F$
• C. $240F$
• D. None of the above

Answer 1

Answer: (A)

$240pF$

Answer 2

$C = 4\pi\varepsilon_{0}K\left\lbrack \frac{ab}{b - a} \right\rbrack = \frac{1}{9 \times 10^{9}}.6\left\lbrack \frac{12 \times 9 \times 10^{- 4}}{3 \times 10^{- 2}} \right\rbrack$

$= 24 \times 10^{- 11} = 240pF$