Question

The radii of two spheres forming a spherical condenser are $0.5$ and $0.6 \,m$. If a medium having dielectric constant $6$ is completely filled in between, the capacity of the condenser will be

• A. $3.3 \times 10^{-10} \,F$
• B. $2 \times 10^{-9} \,F$
• C. $ 2\,F$
• D. $18\,F$

Answer 1

Answer: (B)

Capacity of spherical condenser is
$C=4 \pi \varepsilon_{0} \frac{K a b}{b-a}$
$=\frac{6 \times 0.5 \times 0.6}{9 \times 10^{9}(0.6-0.5)}$
$=\frac{1.8}{0.9 \times 10^{9}}=2 \times 10^{-9} \,F$