Question
What is the phase relationship between the current through and the voltage across a series resonant circuit at resonance?
Answer Options
- A) The voltage leads the current by 90 degrees
- B) The current leads the voltage by 90 degrees
- C) The voltage and current are in phase
- D) The voltage and current are 180 degrees out of phase
Correct Answer: C
Explanation
In an AC circuit, the phase relationship between voltage and current is determined by the net reactive component. Inductive components cause voltage to lead current, while capacitive components cause current to lead voltage (often remembered by the mnemonic ‘ELI the ICE man’).
In a series resonant circuit, the condition for resonance is that the inductive reactance (X_L) exactly cancels the capacitive reactance (X_C). This makes the circuit purely resistive, with zero net reactance. Since only resistance remains, the circuit behaves exactly like a simple resistor. Therefore, the voltage and current are in phase (0 degrees difference) across a series resonant circuit at resonance.
This topic was automatically created to facilitate community discussion about this exam question. Feel free to share study tips, memory tricks, or additional explanations!