Question

A capacitor consists of two similar square aluminium plates, each 10 cm × 10 cm mounted parallel and opposite to each other. What is their capacitance in μ F when distance between them is 1 cm and the dielectric is air

Answer 1

The capacity of a flat capacitor is $C=\cfrac{\epsilon \cdot\epsilon_0 \cdot S}{d}$

Where

$\epsilon=1$

$\epsilon_0=8.85 \cdot 10^{-12} \cfrac{F}{m}$

$S=0.1 \cdot 0.1 m^2=1 \cdot 10^{-2} m^2$

$d=1 \cdot 10^{-2} m$

Then

$C=\cfrac{1 \cdot8.85 \cdot 10^{-12} \cdot 1 \cdot 10^{-2}}{1 \cdot 10^{-2}}=8.85 \cdot 10^{-12}F=0.00885\mu F$