Question Detail

PHY 102 Current Electricity Objective Question

Question

In a discharging RC circuit, what fraction of the initial charge (Q₀) remains on the capacitor after one time constant (τ)?
Options
A Approximately 36%
Correct Answer
B Approximately 50%
C Approximately 64%
D Approximately 100%
Correct Answer

Option A is the correct answer.

Detailed Explanation

Page 29 states that during discharging, 'Charge on plates DROPS by 64%'. This implies that 100% - 64% = 36% of the initial charge remains. Mathematically, at t = τ, q(τ) = Q₀ e⁻¹ ≈ Q₀ * 0.3678.

Hint

Use the formula q(t) = Q₀ e⁻ᵗ/ᴿᶜ and substitute t = τ.

Question Info