AC theoryQuestion 921 of 1506

A resistive AC circuit has 120 V RMS across a 30 Ω resistor and a 10 Ω resistor in series. What is the RMS current?

4 A
12 A
3 A
0.33 A

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Correct answer: 3 A

In a purely resistive circuit the DC rules apply. R total = 40 Ω, so I = 120 / 40 = 3 A.

Source: Lessons in Electric Circuits II: AC (Kuphaldt), 1.4: Simple AC Circuit Calculations

Questions last reviewed: 18 October 2026

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