Red Seal Electrician Practice
AC theoryQuestion 1149 of 1506

A coil has 30 ohms of resistance and 40 ohms of inductive reactance on a 120 V supply. What is the line current?

  1. 1.7 A
  2. 4.0 A
  3. 3.0 A
  4. 2.4 A
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Correct answer: 2.4 A

The impedance is the polar magnitude of the resistance and reactance: sqrt(30 squared + 40 squared) = 50 ohms. I = 120 V / 50 ohms = 2.4 A.

Source: Lessons in Electric Circuits II: AC (Kuphaldt), 11.1: Power in Resistive and Reactive AC circuits

Practice ac theory

Questions last reviewed: 18 October 2026