Red Seal Electrician Practice
AC theoryQuestion 947 of 1506

A real coil is made of copper wire. How does this affect its impedance?

  1. It has series resistance, so impedance is partly resistive.
  2. Its impedance is purely reactive at every frequency.
  3. Its impedance has no resistance but extra capacitance.
  4. Its impedance is zero when connected to DC.
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Correct answer: It has series resistance, so impedance is partly resistive.

Wire resistance acts as if in series with the ideal inductance.

Source: Lessons in Electric Circuits II: AC (Kuphaldt), 3.5: Inductor Quirks

Practice ac theory

Questions last reviewed: 18 October 2026