Resonance in AC Circuits: Master the Fundamentals with Interactive Quizzes

Question 1

Which of the following conditions is essential for resonance in AC circuits?

Accepted Answer

Equivalent inductance and capacitance

Answer

Equivalent resistance and capacitance

Answer

Equivalent resistance and inductance

Answer

Equivalent reactance and impedance

Question 2

In a series RLC circuit, what is the equation for its resonant frequency?

Accepted Answer

f = 1 / (2π√LC)

Answer

f = 1 / (2π√RC)

Answer

f = 1 / (2π√RL)

Answer

f = 2π√LC

Question 3

What is the relationship between the quality factor (Q) of a resonant circuit and its bandwidth?

Accepted Answer

Q is inversely proportional to bandwidth

Answer

Q is directly proportional to bandwidth

Answer

Q is equal to bandwidth

Answer

Q has no relation to bandwidth

Question 4

When does resonance occur in a parallel RLC circuit?

Accepted Answer

Inductive reactance equals capacitive reactance

Answer

Inductive reactance exceeds capacitive reactance

Answer

Capacitive reactance exceeds inductive reactance

Answer

Resistance is minimized

Question 5

Which method is used to calculate the resonant frequency of an LC circuit?

Accepted Answer

f = 1 / (2π√LC)

Answer

Measuring voltage across the inductor and capacitor

Answer

Observing current through the circuit

Answer

Using an oscilloscope to monitor the phase shift

Question 6

In a series resonant circuit, at resonance, the inductive reactance (XL) is equal to:

Accepted Answer

XC

Answer

0

Answer

0.5XC

Answer

4XC

Question 7

Which of the following does NOT affect the resonant frequency of a parallel resonant circuit?

Accepted Answer

Quality factor (Q)

Answer

Inductance (L)

Answer

Capacitance (C)

Answer

Source frequency

Question 8

The Q-factor of a circuit is a measure of its:

Accepted Answer

Selectivity

Answer

Power loss

Answer

Resonant frequency

Answer

Capacitance

Question 9

In a series resonant circuit, the maximum voltage across the capacitor is:

Accepted Answer

Greater than the source voltage

Answer

Equal to the source voltage

Answer

Less than the source voltage

Answer

Zero

Question 10

The bandwidth of a resonant circuit is defined as:

Accepted Answer

The range of frequencies over which the power loss is within a certain range

Answer

The frequency at which the power transfer is maximum

Answer

The difference between the resonant frequency and the cutoff frequency

Answer

The ratio of the resonant frequency to the bandwidth

Question 11

Which of the following is NOT an application of resonance in electrical engineering?

Accepted Answer

Solar cells

Answer

Frequency-selective filters

Answer

Oscillators

Answer

Tuned amplifiers

Question 12

The resonant frequency of a series RLC circuit is given by:

Accepted Answer

f = 1 / (2π√LC)

Answer

f = √(LC)

Answer

f = 1 / (LC)

Answer

f = 2π√(LC)

Question 13

Which of the following can decrease the Q-factor of a circuit?

Accepted Answer

High resistance

Answer

Low capacitance

Answer

Zero inductance

Answer

Ideal voltage source

Question 14

At resonance in a series RLC circuit, the inductive reactance is:

Accepted Answer

Equal to the capacitive reactance

Answer

Less than the capacitive reactance

Answer

Greater than the capacitive reactance

Answer

Zero

Question 15

The power factor of an AC circuit at resonance is:

Accepted Answer

Unity

Answer

Lagging

Answer

Leading

Answer

Zero

Question 16

The resonant frequency of a parallel RLC circuit is:

Accepted Answer

Higher than that of a series RLC circuit with the same components

Answer

Lower than that of a series RLC circuit with the same components

Answer

Equal to that of a series RLC circuit with the same components

Answer

Cannot be determined without specific component values

Question 17

In a resonant series RLC circuit, the phase angle between voltage and current is:

Accepted Answer

0 degrees

Answer

90 degrees

Answer

180 degrees

Answer

Depends on the values of R, L, and C

Question 18

What is the impedance of a series RLC circuit at resonance?

Accepted Answer

Zero

Answer

Infinite

Answer

Equal to resistance

Answer

Equal to reactance

Question 19

What does the quality factor (Q) of a circuit at resonance represent?

Accepted Answer

The ratio of resonant frequency to bandwidth

Answer

The ratio of inductance to capacitance

Answer

The ratio of reactance to resistance

Answer

The ratio of power dissipated to power stored

Question 20

What is the phase relationship between voltage and current in a series RLC circuit at resonance?

Accepted Answer

In phase

Answer

90 degrees out of phase

Answer

180 degrees out of phase

Answer

120 degrees out of phase

Question 21

What happens to the impedance of an ideal LC circuit at resonance?

Accepted Answer

Becomes purely resistive

Answer

Increases

Answer

Decreases

Answer

Remains constant

Question 22

What happens to the voltage across the inductor and capacitor in a parallel RLC circuit at resonance?

Accepted Answer

They are equal in magnitude and in phase

Answer

They are equal in magnitude but opposite in phase

Answer

They are both zero

Answer

They are in phase but not equal in magnitude

Question 23

Which of the following is NOT an advantage of using resonance in electrical circuits?

Accepted Answer

Increased power loss

Answer

Increased power transfer

Answer

Improved signal-to-noise ratio

Answer

Reduced harmonic distortion

Question 24

Which condition represents the state of resonance in a series AC circuit, where the inductive reactance (XL) and capacitive reactance (XC) are balanced?

Accepted Answer

XL = XC

Answer

XL > XC

Answer

XL < XC

Answer

R = XL

Question 25

In a series AC circuit, the quality factor 'Q' is defined as the ratio of:

Accepted Answer

Resonant frequency to resistance

Answer

Inductive reactance to capacitive reactance

Answer

Inductive reactance to resistance

Answer

Capacitive reactance to resistance

Question 26

If the frequency in a series AC circuit is below the resonant frequency, the circuit current is:

Accepted Answer

Minimum

Answer

Maximum

Answer

Unaffected

Answer

180 degrees out of phase with the voltage

Question 27

In a parallel AC circuit at resonance, what is the voltage drop across the inductor and capacitor?

Accepted Answer

Equal in magnitude but 180 degrees out of phase

Answer

Equal in magnitude and in phase

Answer

Unequal in magnitude and in phase

Answer

Unequal in magnitude but 90 degrees out of phase

Question 28

What is the primary purpose of a tuned circuit in a resonant system?

Accepted Answer

To selectively allow specific frequencies to pass

Answer

To enhance the amplitude of certain frequencies

Answer

To block out unwanted frequencies

Answer

To create a state of resonance in the circuit

Question 29

In a series RLC circuit, what formula is used to calculate the resonant frequency?

Accepted Answer

f = 1/(2π * √LC)

Answer

f = 1/(2π * R * C)

Answer

f = L/C

Answer

f = R/C

Question 30

At resonance, the phase difference between the voltage and current in a series RLC circuit is:

Accepted Answer

0 degrees

Answer

90 degrees

Answer

180 degrees

Answer

270 degrees

Question 31

In a series RLC circuit, the quality factor (Q) represents:

Accepted Answer

The ratio of stored energy to dissipated energy per cycle

Answer

The ratio of inductor's resistance to capacitor's resistance

Answer

The ratio of inductive reactance to capacitive reactance

Answer

The ratio of bandwidth to resonant frequency

Question 32

The impedance of a series RLC circuit at resonance is:

Accepted Answer

Minimum

Answer

Maximum

Answer

Zero

Answer

Infinite

Question 33

Which circuit configuration exhibits a wider bandwidth?

Accepted Answer

Parallel RLC circuit

Answer

Series RLC circuit

Answer

Neither, they have the same bandwidth

Answer

Depends on component values

Question 34

At resonance in an RLC circuit, the impedance is:

Accepted Answer

Minimum

Answer

Zero

Answer

Maximum

Answer

Infinite

Question 35

Regarding the phase angle at resonance in an RLC circuit, which statement is correct?

Accepted Answer

The phase angle is zero, indicating that the current and voltage are in phase.

Answer

The phase angle is 90 degrees, indicating that the current leads the voltage.

Answer

The phase angle is -90 degrees, indicating that the current lags the voltage.

Question 36

In a parallel RLC circuit used for radio reception, how does the circuit achieve selectivity?

Accepted Answer

The circuit exhibits a high impedance at the resonant frequency, allowing only the desired signal to pass through.

Answer

The circuit exhibits a low impedance at the resonant frequency, filtering out unwanted signals.

Question 37

Which factor primarily determines the bandwidth of a resonant circuit?

Accepted Answer

The quality factor (Q) of the circuit.

Answer

The resonant frequency of the circuit.

Answer

The capacitance of the circuit.

Question 38

Which of the following factors does NOT affect the resonant frequency of an RLC circuit?

Accepted Answer

Resistance

Answer

Inductance

Answer

Capacitance

Question 39

In a series RLC circuit at resonance, the current is maximum because:

Accepted Answer

The impedance is minimum, allowing maximum current flow.

Answer

The voltage across the inductor is maximum.

Answer

The voltage across the capacitor is maximum.

Question 40

In a parallel RLC circuit used as a band-pass filter, what is the effect of increasing the circuit's quality factor?

Accepted Answer

The bandwidth of the filter decreases, resulting in a narrower passband.

Answer

The bandwidth of the filter increases, resulting in a wider passband.

Answer

The resonant frequency of the filter increases.

Question 41

Which of the following applications utilize the principle of resonance in AC circuits?

Accepted Answer

All of the above.

Answer

Power factor correction

Answer

LC oscillators

Answer

Radio tuning

Question 42

In a series RLC circuit, the condition for resonance occurs when:

Accepted Answer

The inductive reactance (XL) is equal to the capacitive reactance (XC)

Answer

The resistance (R) is zero

Answer

XL is greater than XC

Answer

XL is less than XC

Question 43

What is the quality factor (Q) of a series RLC circuit?

Accepted Answer

Q = XL / R

Answer

Q = R / XL

Answer

Q = R / XC

Answer

Q = XC / R

Question 44

Which of the following is a disadvantage of resonance in AC circuits?

Accepted Answer

Increased power factor

Answer

Increased voltage gain

Answer

Reduced current

Question 45

In a parallel RLC circuit, the resonant frequency occurs when:

Accepted Answer

XL is equal to XC

Answer

R is zero

Answer

XL is greater than XC

Answer

XL is less than XC

Question 46

Which of the following instruments can be used to detect resonance in AC circuits?

Accepted Answer

Oscilloscope

Answer

Ammeter

Answer

Voltmeter

Answer

Multimeter

Question 47

What is the effect of increasing the inductance of a series RLC circuit on the resonant frequency?

Accepted Answer

Decreases

Answer

No change

Answer

Increases

Answer

Depends on the capacitance

Question 48

Which of the following is an example of how resonance is utilized in real-world applications?

Accepted Answer

Tuning radio receivers

Answer

Measuring inductance

Answer

DC power transmission

Question 49

What is the bandwidth of a series RLC circuit?

Accepted Answer

BW = R / L

Answer

BW = C / R

Answer

BW = L / C

Answer

BW = R / C

Question 50

What is the power factor of a circuit at resonance?

Accepted Answer

1

Answer

0

Answer

Depends on the resistance

Answer

0.5