Question Detail
Question
A parallel plate air capacitor is made using two plates 0.2 m² spaced 1 cm apart. It is connected to a 50 V battery. What is the charge on each plate? (Permittivity of free space ε0 = 8.85 × 10-12 F/m)
Correct Answer
Option C is the correct answer.
Detailed Explanation
The capacitance of a parallel plate capacitor is C = ε0A/d. The charge stored on the plates is Q = CV.Given: A = 0.2 m², d = 1 cm = 0.01 m, V = 50 V.C = (8.85 × 10⁻¹² F/m) × (0.2 m²) / (0.01 m) = 177 × 10⁻¹² F = 177 pF.Q = CV = (177 × 10⁻¹² F) × (50 V) = 8850 × 10⁻¹² C = 8.85 × 10⁻⁹ C = 8.85 nC.
Hint
First calculate the capacitance using the given dimensions and then use Q = CV.