Two identical resistors are parallel to each other,and the combination is in series with a 5.0-nF capacitor,in a circuit with a switch open.If initially 15.0 V is across the capacitor,and 11 ns later the voltage across the resistor pair is 2.5 V,what is the resistance of each resistor?
A)2.5 $\varOmega$
B)1.2$\varOmega$
C)0.12 $\varOmega$
D)0.24$\varOmega$

Question

Quizplus · Accepted Answer

The time constant for the circuit is RC, where R is the resistance of each resistor and C is the capacitance. The voltage across the resistor pair is given by V = V0e^(-t/RC), where V0 is the initial voltage across the capacitor. Substituting the given values, we get 2.5 V = 15.0 V * e^(-11 ns / (R * 5.0 nF)). Solving for R, we get R = 1.2 $\varOmega$.

Two Identical Resistors Are Parallel to Each Other,and the Combination Ω\varOmegaΩ

Two Identical Resistors Are Parallel to Each Other,and the Combination $\varOmega$