in a series R-L-C circuit at resonance, the voltages across the resistor and the inductor are 30V and 40V respectively, what is the voltage across the capacitor?
A. 30V B. 40V C. 50V D. 70V
Correct Answer: B
Explanation
At resonance, inductive reactant XL is equal to the capacitive reactance XC i.e. XL = XC and XL = VL/IL and XC = VC/IC Again since the components are in series, the same current flows in the series arrangment i.e. IL = IC at resonance, VL/IL = VC/IC ∴ VL = VC = 40V
