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PHY 102 Test Compilation PHY 102 15 Objective Question

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?
Options
A 2.85nC
B 9.15nC
C 8.85nC
Correct Answer
D 2.05nC
Correct Answer

Option C is the correct answer.

Detailed Explanation

First, calculate the capacitance: C = ε₀A/d. Given A = 0.2 m², d = 1 cm = 0.01 m, and the permittivity of free space ε₀ ≈ 8.854 × 10⁻¹² F/m, C = (8.854 × 10⁻¹² F/m × 0.2 m²) / 0.01 m = 1.7708 × 10⁻¹⁰ F. Next, calculate the charge using Q = CV. Given V = 50 V, Q = (1.7708 × 10⁻¹⁰ F) × 50 V = 8.854 × 10⁻⁹ C = 8.854 nC.

Hint

First calculate the capacitance of the parallel plate capacitor, then use the capacitance and voltage to find the charge.

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