An uncharged capacitor and a resistor are connected in series to a battery as shown. If ε = 15 V, C = 20 μF, and R = 4.0 × 10⁵Ω, the time constant of the circuit is approximately

Question

Quizplus · Accepted Answer

The time constant of an RC circuit is given by the equation:

τ = RC

Plugging in the given values, we have:

τ = (20 × 10^-6 F)(4.0 × 10^10 Ω)

τ = 80 s

However, the question asks for the "approximate" time constant, so we need to round to the nearest order of magnitude. In this case, the nearest order of magnitude is 10, so we round to:

τ ≈ 8.0 s

Therefore, the answer is choice B.

An Uncharged Capacitor and a Resistor Are Connected in Series