Extra exam question E5A03
Subelement E5, ELECTRICAL PRINCIPLES· Group E5A
What is the magnitude of the impedance of a series RLC circuit at resonance?
- A.High, compared to the circuit resistance
- B.Approximately equal to capacitive reactance
- C.Approximately equal to inductive reactance
- D.Approximately equal to circuit resistance (correct answer)
WhyThe magnitude of a series RLC circuit's impedance at resonance is approximately equal to the circuit's resistance. At resonance in a series RLC circuit, the inductive and capacitive reactances cancel exactly, leaving only the circuit's resistance to determine the total impedance, so the magnitude of the impedance at resonance is approximately equal to the circuit resistance, answer D. It isn't high compared to resistance, and it isn't approximately equal to either reactance alone, both reactances have already canceled out of the total by that point.
Published 2026-08-28 · Last updated 2026-08-28 · Question text is verbatim from the 2024-2028 NCVEC Element 4 pool (public domain); the explanation above is original writing, see our methodology.
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