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.