Question

The diameter of the plate of a parallel plate condenser is $6\,cm$. If its capacity is equal to that of a sphere of diameter $200\, cm$, the separation between the plates of the condenser is

• A. $4.5 \times 10^{-4} m$
• B. $2.25 \times 10^{-4} m$
• C. $6.75 \times 10^{-4} m$
• D. $9 \times 10^{-4} m$

Answer 1

Answer: (B)

$As \frac{\varepsilon_{0}A}{d}=4\pi\varepsilon_{0}R$
$d=\frac{A}{4\pi R}=\frac{\pi\left(6/2 \right)^{2}}{4\pi\left(100\right)}=2.25\times10^{-2} cm$
$= 2.25 \times 10^{-4} m$