AC theoryQuestion 1475 of 1506

A series circuit has a resistance of 25 Ω and an inductive reactance of 50 Ω. What is the impedance?

  1. 37.5 Ω
  2. 25.0 Ω
  3. 35.4 Ω
  4. 55.9 Ω
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Correct answer: 55.9 Ω

Z = √(R² + X²) = √(25² + 50²) = 55.9 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