In a series RLC circuit the rms voltage across the resistor is 80.0 V, across the capacitor is 120 V, and across the inductor is 60.0 V. What is the rms voltage applied to this circuit?
A) 60.0 V
B) 80.0 V
C) 100 V
D) 120 V
E) 140 V

Question

Quizplus · Accepted Answer

The rms voltage applied to a series RLC circuit is found by subtracting the voltage across the capacitor from the sum of the voltages across the resistor and inductor, due to the phase difference between them, and then taking the square root of the sum of the squares of these voltages. Thus, $V_{rms} = \sqrt{V_R^2 + (V_L - V_C)^2} = \sqrt{80^2 + (60 - 120)^2} = \sqrt{6400 + 3600} = \sqrt{10000} = 100 V.$

In a Series RLC Circuit the Rms Voltage Across the Resistor