Red Seal Electrician Practice
AC theoryQuestion 933 of 1506

A pure inductor carries AC. When is the voltage across it at its peak?

  1. When the current changes fastest, at its zero crossing
  2. When the current is at its positive peak value
  3. When the current is at its negative peak value
  4. It is constant at all times in the cycle
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Correct answer: When the current changes fastest, at its zero crossing

Inductor voltage depends on the rate of change of current. The current changes fastest at its zero crossing.

Source: Lessons in Electric Circuits II: AC (Kuphaldt), 3.2: AC Inductor Circuits

Practice ac theory

Questions last reviewed: 18 October 2026