AC theoryQuestion 1476 of 1506

A series circuit has a resistance of 20 Ω and an inductive reactance of 40 Ω. What is the impedance?

  1. 20.0 Ω
  2. 30.0 Ω
  3. 60.0 Ω
  4. 44.7 Ω
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Correct answer: 44.7 Ω

Z = √(R² + X²) = √(20² + 40²) = 44.7 Ω. Resistance and reactance are 90° apart, so they do not add directly.

Source: Computed, 3.3: Series Resistor-Inductor Circuits

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Questions last reviewed: 18 October 2026