A resistor and capacitor are connected in series with an applied AC voltage source.Separate voltmeter readings across the resistor and capacitor give values of 50 V and 75 V (rms),respectively.What is the effective (rms)voltage of the source?
A)25 V
B)63 V
C)90 V
D)125 V

Question

Quizplus · Accepted Answer

In a series circuit, the voltage drops across each component add up to the total voltage of the source. 
So, Vsource = Vresistor + Vcapacitor 
RMS voltage of resistor = 50 V 
RMS voltage of capacitor = 75 V 
Thus, Vsource = 50 V + 75 V = 125 V (rms) 
Therefore, the correct choice is option (D) 125 V.

A Resistor and Capacitor Are Connected in Series with an Applied