Red Seal Electrician Practice
AC theoryQuestion 1480 of 1506

A series circuit has a resistance of 10 Ω and a capacitive reactance of 75 Ω. What is the impedance?

  1. 42.5 Ω
  2. 75.7 Ω
  3. 85.0 Ω
  4. 27.4 Ω
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Correct answer: 75.7 Ω

Z = √(R² + X²) = √(10² + 75²) = 75.7 Ω. Resistance and reactance are 90° apart, so they do not add directly.

Source: Computed, 4.3: Series Resistor-Capacitor Circuits

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Questions last reviewed: 18 October 2026