RLC Circuits and Resonance Objective Questions and Answers - ObjectiveBooks

# Practice Test: Question Set - 03

1. A 9 mH coil is in parallel with a 0.015 μF capacitor across an 18 kHz ac source. The coil's internal resistance RW, is 60 Ω. The circuit impedance is
(A) 17,340 Ω
(B) 1,734 Ω
(C) 290 Ω
(D) 1,018 Ω

2. A resonant circuit has a lower critical frequency of 7 kHz and an upper critical frequency of 13 kHz. The bandwidth of the circuit is
(A) 7 kHz
(B) 13 kHz
(C) 20 kHz
(D) 4 kHz

3. A 200 Ω resistor, a coil with 30 Ω of reactance, and a capacitor of unknown reactance are in series across an ac source. The circuit is at resonance. Circuit impedance is
(A) 230 Ω
(B) 170 Ω
(C) 200 Ω
(D) Cannot be determined

4. At series resonance, the inductive reactance and capacitive reactance are never equal.
(A) True
(B) False

5. A certain series resonant circuit has a bandwidth of 2 kHz. If the existing coil is replaced with one having a higher value of Q, the bandwidth will
(A) Increase
(B) Remain the same
(C) Decrease
(D) Be less selective

6. In a series RLC circuit, the larger reactance determines the net reactance of the circuit.
(A) True
(B) False

7. A resistor of 3 kΩ, a 0.05 μF capacitor, and a 120 mH coil are in series across a 5 kHz, 20 V ac source. What is the impedance, expressed in polar form?
(A) 636 Ω
(B) 3,769 Ω
(C) 433 Ω
(D) 4,337 Ω

8. A 10 Ω resistor, a 90 mH coil, and a 0.015 μF capacitor are in series across an ac source. The impedance magnitude at 1,200 Hz below fr is
(A) 1,616 Ω
(B) 161 Ω
(C) 3,387 Ω
(D) 1,771 Ω

9. A lower Q produces a narrower bandwidth.
(A) True
(B) False

10. In a certain series resonant circuit, VC = 125 V, VL = 125 V, and VR = 40 V. The value of the source voltage is
(A) 125 V
(B) 250 V
(C) 290 V
(D) 40 V

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