Extra exam question E5B11
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 25 ohms, R is 100 ohms, and XL is 75 ohms?
- A.27 degrees with the voltage lagging the current
- B.27 degrees with the voltage leading the current (correct answer)
- C.63 degrees with the voltage lagging the current
- D.63 degrees with the voltage leading the current
WhyA series RLC circuit with XC of 25 ohms, R of 100 ohms, and XL of 75 ohms has a phase angle of about 27 degrees, with the voltage leading the current. With XC at 25 ohms and XL at 75 ohms, the net reactance is 75 minus 25, or positive 50 ohms, inductive overall, and dividing that by the 100 ohm resistance and taking the arctangent gives a phase angle of about 27 degrees; since the net reactance is inductive, the voltage leads the current, answer B. The larger 63 degree figure and a voltage-lagging 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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