# Problems of Series Resonance Involving Quality Factor MCQ’s

This set of Network Theory Multiple Choice Questions & Answers (MCQs) focuses on “Problems of Series Resonance Involving Quality Factor”.

1. A circuit tuned to a frequency of 1.5 MHz and having an effective capacitance of 150 pF. In this circuit, the current falls to 70.7 % of its resonant value. The frequency deviates from the resonant frequency by 5 kHz. Effective resistance of the circuit is?
a) 2 Ω
b) 3 Ω
c) 5.5 Ω
d) 4.7 Ω

2. Consider a circuit consisting of two capacitors C1 and C2. Let R be the resistance and L be the inductance which are connected in series. Let Q1 and Q2 be the quality factor for the two capacitors. While measuring the Q value by the Series Connection method, the value of the Q factor is?
a) Q = (C1–C2)Q1Q2Q1C1−Q2C2
b) Q = (C2–C1)Q1Q2Q1C1−Q2C2
c) Q = (C1–C2)Q1Q2Q2C2−Q1C1
d) Q = (C2–C1)C1C2Q1C1−Q2C2

3. A circuit tuned to a frequency of 1.5 MHz and having an effective capacitance of 150 pF. In this circuit, the current falls to 70.7 % of its resonant value. The frequency deviates from the resonant frequency by 5 kHz. Q factor is?
a) 50
b) 100
c) 150
d) 200

4. Consider a circuit consisting of two capacitors C1 and C2. Let R be the resistance and L be the inductance which are connected in series. Let Q1 and Q2 be the quality factor for the two capacitors. While measuring the Q value by the Parallel Connection method, the value of the Q factor is?
a) Q = (C1–C2)Q1Q2Q1C1−Q2C2
b) Q = (C2–C1)Q1Q2Q1C1−Q2C2
c) Q = (C1–C2)Q1Q2Q2C2−Q1C1
d) Q = (C2–C1)C1C2Q1C1−Q2C2

5. For the resonant circuit given below, the value of the quality factor of the circuit is __________

a) 5.6
b) 7.1
c) 8.912
d) 12.6

6. For the series resonant circuit given below, the value of the quality factor is ___________

a) 15
b) 36
c) 25
d) 10

7. A 50 Hz voltage is measured with a moving iron voltmeter and a rectifier type AC voltmeter connected in parallel. If the meter readings are Va and Vb respectively. Then the form factor may be estimated as?
a) VaVb
b) 1.11VaVb
c) 2√VaVb
d) πVaVb

8. For the series resonant circuit shown below, the value of the resonant frequency is _________

a) 36.84 kHz
b) 40.19 kHz
c) 25.28 kHz
d) 15.9 kHz

9. For the series resonant circuit given below, the bandwidth is ____________

a) ±351 Hz
b) ±796 Hz
c) ±531 Hz
d) ±225 Hz

10. In a series resonance type BPF, C = 1.8 pf, L = 25 mH, RF = 52 Ω and RL = 9 kΩ. The Resonant frequency f is __________

a) 75.1 kHz
b) 751 kHz
c) 575 kHz
d) 57.5 kHz

11. A 50 μF capacitor, when connected in series with a coil having a resistance of 40Ω, resonates at 1000 Hz. The inductance of the coil for the resonant circuit is ____________
a) 2.5 mH
b) 1.2 mH
c) 0.5 mH
d) 0.1 mH

12. For the series circuit given below, the value of the cut-off frequencies are ____________

a) 78.235 kHz; 16.215 kHz
b) 13.135 kHz; 81.531 kHz
c) 16.716 kHz; 15.124 kHz
d) 50.561 kHz; 18.686 kHz

13. In a series resonance type BPF, C = 1.8 pf, L = 25 mH, RF = 52 Ω and RL = 9 kΩ. The Bandwidth is ___________

a) 331 kHz
b) 575 kHz
c) 331 Hz
d) 575 Hz

14. A coil (which can be modelled as a series RL circuit) has been designed for a high Quality Factor (Q) performance. The voltage is rated at and a specified frequency. If the frequency of operation is increased 10 times and the coil is operated at the same rated voltage. The new value of Q factor and the active power P will be?
a) P is doubled and Q is halved
b) P is halved and Q is doubled
c) P remains constant and Q is doubled
d) P decreases 100 times and Q is increased 10 times

15. A 50 Hz, bar primary CT has a secondary with 800 turns. The secondary supplies 7 A current into a purely resistive burden of 2 Ω. The magnetizing ampere-turns are 300. The phase angle is?
a) 3.1°
b) 85.4°
c) 94.6°
d) 175.4°