Question

The radius of each plate in a parallel plate capacitor is 10cm . If the distance between the plates is $10cm$ , then calculate the capacitance of capacitor filled with air .

Answer 1

Radius of plate = $10cm$ = $10\times {10}^{-2}m$
Cross sectional area of plate ($A$) = $\pi r^2$ $=\pi \times (10\times {10}^{-2}{)}^2$
Distance between plate ($d$) = $10cm$ = $10\times {10}^{-2}m$
Capacitance of parallel plate capacitor :
$C=\frac{{\epsilon }_{0}A}{d}$
$C=\frac{8.86\times {10}^{-12}\times 3.14\times (10\times {10}^{-2}{)}^2}{10\times {10}^{-2}}$ = $2.78\times {10}^{-12}$
$C=2.78pF$