In a series circuit consisting of a 12.0 V source of emf, a 2.00 mF capacitor, a 1.00 kΩ resistor and a switch, what is the voltage across the capacitor at a time of one time constant t after the switch is closed?
A) 0.632 V
B) 6.32 V
C) 7.59 V
D) 8.65 V

Question

Quizplus · Accepted Answer

The time constant of the circuit is given by: 
τ = RC = (1.00 kΩ)(2.00 mF) = 2.00 seconds
One time constant is equal to 2.00 seconds. Therefore, at t = τ, the voltage across the capacitor is given by:
V = V0(1 - e^(-t/τ))
V = (12.0 V)(1 - e^(-2.00/2.00))
V ≈ 7.59 V
Therefore, the answer is (C) 7.59 V.

In a Series Circuit Consisting of a 12