Extra exam question E5B08
Subelement E5, ELECTRICAL PRINCIPLES· Group E5B
What is the phase angle between the voltage across and the current through a series RLC circuit if XC is 300 ohms, R is 100 ohms, and XL is 100 ohms?
- A.63 degrees with the voltage lagging the current (correct answer)
- B.63 degrees with the voltage leading the current
- C.27 degrees with the voltage leading the current
- D.27 degrees with the voltage lagging the current
WhyA series RLC circuit with XC of 300 ohms, R of 100 ohms, and XL of 100 ohms has a phase angle of about 63 degrees, with the voltage lagging the current. With XC at 300 ohms and XL at 100 ohms, the net reactance is 100 minus 300, or negative 200 ohms, capacitive overall, and dividing that by the 100 ohm resistance and taking the arctangent gives a phase angle of about 63 degrees; since the net reactance is capacitive, the voltage lags the current, answer A. The smaller 27 degree figure and a voltage-leading description belong to a different combination of reactances than the one given here.
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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