USCG Exam PracticeDC circuits and electronic principles
A series RLC circuit operating at a frequency where XL = XC has R = 5 Ω, XL = 40 Ω, and XC = 40 Ω. The applied voltage is 50 V. What is the current in the circuit, and what is the impedance?
- A. I = 1.22 A; Z = 40.3 Ω
- ✓ I = 10 A; Z = 5 ΩCorrect
- C. I = 0.625 A; Z = 80 Ω
- D. I = 1.25 A; Z = 40 Ω
Why B is correct
NEETS Mod. 2 §4-1: at resonance XL = XC, so net reactance X = XL − XC = 0. Impedance Z = √(R² + 0²) = R = 5 Ω. Current I = E/Z = 50/5 = 10 A. This is the condition of maximum current in a series resonant circuit.
Cited:NEETS Mod. 2 §4-1