Red Seal Electrician Practice
AC theoryQuestion 976 of 1506

An AC current flows through an impedance that has both resistance and reactance. How far is the voltage drop out of phase with the current?

  1. Exactly 0 degrees, as in a resistor
  2. Somewhere between 0 and 90 degrees
  3. Exactly 90 degrees, as in a pure reactance
  4. More than 90 degrees behind the current
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Correct answer: Somewhere between 0 and 90 degrees

Impedance combines the in-phase resistance and the 90-degree reactance.

Source: Lessons in Electric Circuits II: AC (Kuphaldt), 5.1: Review of R, X, and Z

Practice ac theory

Questions last reviewed: 18 October 2026