Answer:
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