Question

In a parallel plate capacitor with air between the plates, each plate has an area of 6 × 10-3 m2 and the distance between the plates is 3 mm. Calculate the capacitance of the capacitor. If this capacitor is connected to a 100 V supply, what is the charge on each plate of the capacitor?

Answer 1

Area of each plate of the parallel plate capacitor, A = 6 × 10−3 m2

Distance between the plates, d = 3 mm = 3 × 10−3 m Supply voltage, V = 100 V

Capacitance C of a parallel plate capacitor is given by, $C =\frac{E0A}{D}$

Where, ε0= Permittivity of free space = 8.854 × 10−12 N−1 m−2 C−2

$C = \frac{8.854×10×6×10^{-3}}{3×10^-3} = 17.71 × 10^{-12}F = 17.71 pF$

So, charge on each plate of the capacitor

q = VC = 100 × 17.71 × 10-12 C = 1.771 × 10-9C

Therefore, capacitance of the capacitor is 17.71 pF and charge on each plate is 1.771 × 10−9 C.