This set of Basic Electrical Engineering Multiple Choice Questions & Answers (MCQs) focuses on “Frequency Variation in a Series RLC Circuit”.

1. If the resonant frequency in a series RLC circuit is 50kHz along with a bandwidth of 1kHz, find the quality factor.

a) 5

b) 50

c) 100

d) 500

View Answer

Explanation: We know that Quality factor is equal to the resonant frequency divided by the bandwidth. Substituting the values from the given question, we get Q=50.

2. What is the SI unit for quality factor?

a) Hz

b) kHz

c) MHz

d) No unit

View Answer

Explanation: We know that Quality factor is equal to the resonant frequency divided by the bandwidth. It is one frequency divided by another hence it has no unit.

3. What happens to the quality factor when the bandwidth increases?

a) Increases

b) Decreases

c) Remains the same

d) Becomes zero

View Answer

Explanation: We know that Quality factor is equal to the resonant frequency divided by the bandwidth. Hence as the bandwidth increases, quality factor decreases.

4. What happens to the quality factor when resonant frequency increases?

a) Increases

b) Decreases

c) Remains the same

d) Becomes zero

View Answer

Explanation: We know that Quality factor is equal to the resonant frequency divided by the bandwidth. Hence as the resonant frequency increases, quality factor also increases.

5. Resonant frequency is when ___________

a) XL=XC

b) XL>XC

c) XL<XC

d) Cannot be determined

View Answer

Explanation: The frequency of a system is said to be resonating when the value of the capacitive reactance and the inductive reactance is the same.

6. What is the frequency in resonance condition?

a) Minimum

b) Maximum

c) Cannot be determined

d) Zero

View Answer

Explanation: At resonance condition, the frequency is maximum since the inductive reactance is equal to the capacitive reactance and the voltage and current are in phase.

7. The current leads the supply voltage in a series RLC circuit has its frequency _________ the resonant frequency.

a) Above

b) Below

c) Equal to

d) Cannot be determined

View Answer

Explanation: The current leads the voltage in a series RLC circuit when the supply voltage is less than the resonant voltage.

8. What is the power factor of a series RLC circuit under resonance condition?

a) 0

b) 1

c) Infinity

d) 100

View Answer

Explanation: The power factor for a series RLC circuit in resonance condition is always 1 because the current is in phase with the voltage under resonance condition.

9. In resonance condition, current ________ voltage.

a) Leads

b) Lags

c) Is in phase with

d) Is greater than

View Answer

Explanation: In resonance condition of a series RLC circuit, the current is always in phase with the voltage because the reactance is neither capacitive nor inductive.

10. What is the correct formula for quality factor?

a) Q=BW*fr

b) Q=BW/fr

c) Q=fr/BW

d) Q=fr2

View Answer

Explanation: The correct formula for quality factor is Q=fr/BW, where fr is the resonant frequency, BW is the bandwidth frequency and Q is the quality factor.

**Sanfoundry Global Education & Learning Series – Basic Electrical Engineering.**

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