Red Seal Electrician Practice
AC theoryQuestion 1146 of 1506

A 120 V source feeds a purely resistive 30 ohm load. What is the power dissipated?

  1. 3600 W
  2. 4 W
  3. 480 W
  4. 120 W
Show answer

Correct answer: 480 W

I = 120 V / 30 ohms = 4 A. P = 120 V x 4 A = 480 W.

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