IP Consider a parallel-plate capacitor constructed from two circular metal plates of radius R. The plates are separated by a distance of 1.4 mm.

(a) What radius must the plates have if the capacitance of this capacitor is to be 1.8

Required radius of the plates = 9.52 m

Explanation:

C = (Aε₀) / d

C = 1.8 * 10⁻⁶ F

A = ?

ε₀ = 8.8542 * 10⁻¹² F/m

d = 1.4 mm = 1.4 * 10⁻³ m

A = Cd/ε₀ = (1.8 * 10⁻⁶) (1.4 * 10⁻³) / (8.8542 * 10⁻¹²) = 281.61 m²

Area of the plate = πr² = 281.61

r² = 281.61/π = 90.59

r = √ (90.59) = 9.52 m