EEE - Passive Filters Quiz (or) MCQ | Questions and Answers

1 .

Passive filters are made up of ___________.

A)

passive components

B)

active components

C)

latest components

D)

None of the above

Correct Answer : passive components

2 .

The maximum output voltage of a certain low-pass filter is 15 V. The output voltage at the critical frequency is _________.

A)

0 V

B)

10.60 V

C)

15 V

D)

21.21 V

Correct Answer : 10.60 V

3 .

What does the high pass filters generally comprise? A. B. C. Inductive series arm D.

A)

Capacitive series arm

B)

Inductive shunt arm

C)

Capacitive shunt arm

D)

Both (A) and (B)

Correct Answer : Both (A) and (B)

4 .

A band-stop filter passes frequencies between its lower and upper critical frequencies and rejects all others.

A)

True

B)

False

C)

Can Not Say

D)

None of the above

Correct Answer : False

5 .

The bandwidth of a resonant filter is determined by the quality factor (Q) of the circuit and the resonant frequency.

A)

True

B)

False

C)

Can Not Say

D)

None of the above

Correct Answer : True

6 .

In a certain parallel resonant band-pass filter, the resonant frequency is 14 kHz. If the bandwidth is 4 kHz, the lower frequency

A)

Is 7 kHz

B)

Is 10 kHz

C)

Is 12 kHz

D)

Cannot be determined

Correct Answer : Is 12 kHz

7 .

A)

0 dB

B)

0.8 dB

C)

8.30 dB

D)

-8.30 dB

Correct Answer : -8.30 dB

8 .

The same signal in Problem 2 is applied to an RC high-pass filter. If the reactance is zero at the input frequency, the output voltage is

A)

Zero

B)

9 V peak-to-peak

C)

12.73 V peak-to-peak

D)

18 V peak-to-peak

Correct Answer : 18 V peak-to-peak

9 .

A sinusoidal voltage with a peak-to-peak value of 18 V is applied to an RC low-pass filter. If the reactance at the input frequency is zero, the output voltage is

A)

Zero

B)

9 V peak-to-peak

C)

12.74 V peak-to-peak

D)

18 V peak-to-peak

Correct Answer : Zero

10 .

In a certain low-pass filter, fc = 3.5 kHz. Its pass-band is

A)

0 Hz

B)

0 Hz to 3.5 kHz

C)

3.5 kHz

D)

7 kHz

Correct Answer : 0 Hz to 3.5 kHz

11 .

An RC high-pass filter consists of a 0.2 µF capacitor and a 220 Ω resistor. The output is taken across the resistor. The circuit's critical frequency is

A)

362 Hz

B)

723 Hz

C)

3,617 Hz

D)

7,234 Hz

Correct Answer : 3,617 Hz

12 .

An RL low-pass filter consists of a 5.6 mH coil and a 3.3 kΩ resistor. The output voltage is taken across the resistor. The circuit's critical frequency is

A)

86.12 kHz

B)

93.8 Hz

C)

861 Hz

D)

93.8 kHz

Correct Answer : 93.8 kHz

13 .

Which parameter determines the amount of signal attenuation in a passive filter?

A)

Impedance

B)

Resistance

C)

Capacitance

D)

Cutoff frequency

Correct Answer : Impedance

Explanation : Impedance is a crucial parameter that determines the amount of signal attenuation in a passive filter. It is a complex quantity that combines the resistance, capacitance, and inductance of the filter elements. The impedance of a filter varies with frequency, allowing it to selectively attenuate or pass certain frequencies.

14 .

Which type of passive filter is commonly used to reduce noise in power supply circuits?

A)

Notch filter

B)

Band-pass filter

C)

High-pass filter

D)

Low-pass filter

Correct Answer : Low-pass filter

Explanation : Low-pass filters are frequently employed in power supply circuits to reduce high-frequency noise and interference. By attenuating the high-frequency components, low-pass filters help ensure a clean and stable DC power supply, minimizing the impact of noise on sensitive electronic components.

15 .

What does the cutoff frequency of a filter represent?

A)

The lowest frequency the filter can pass

B)

The highest frequency the filter can pass

C)

The range of frequencies the filter can pass

D)

The frequency at which the filter attenuates the signal by half

Correct Answer : The frequency at which the filter attenuates the signal by half

Explanation : The cutoff frequency of a filter is the frequency at which the filter attenuates the input signal power by half (-3 dB). It represents the point where the filter begins to transition from passing the signal with minimal attenuation to attenuating it as the frequency increases (in the case of low-pass filters) or decreases (in the case of high-pass filters).

16 .

A series resonant band-stop filter consists of a 68 Ω resistor, a 110 mH coil, and a 0.02 µF capacitor. The internal resistance, RW, of the coil is 4 Ω. Input voltage is 200 mV. Output voltage is taken across the coil and capacitor in series. What is the output voltage magnitude at f0?

A)

1.1 mV

B)

11.1 mV

C)

111 mV

D)

200 mV

Correct Answer : 11.1 mV

17 .

In a series resonant band-pass filter, a lower value of Q results in

A)

A larger bandwidth

B)

A higher impedance

C)

A smaller bandwidth

D)

A higher resonant frequency

Correct Answer : A larger bandwidth

18 .

Critical frequencies are also called -3 dB frequencies.

A)

True

B)

False

C)

Can Not Say

D)

None of the above

Correct Answer : True

19 .

A band-pass filter rejects all frequencies within a band between a lower and an upper critical frequency and passes all others.

A)

True

B)

False

C)

Can Not Say

D)

None of the above

Correct Answer : False

20 .

The roll-off rate of a basic RC or RL filter is 20 dB per decade.

A)

True

B)

False

C)

Can Not Say

D)

None of the above

Correct Answer : True

21 .

A series resonant band-pass filter consists of a 2 mH coil, a 0.005 µF capacitor and a 120 Ω resistor. The winding resistance of the coil is 12 Ω. The output voltage is taken off the resistor. Input voltage is 12 V_rms. What is the output voltage magnitude at the center frequency (f₀)?

A)

1.09 V

B)

1.1 V

C)

10.9 V

D)

12 V

Correct Answer : 10.9 V

22 .

In an RC high-pass filter, the output is taken across the resistor and the output leads the input.

A)

True

B)

False

C)

Can Not Say

D)

None of the above

Correct Answer : True

23 .

An RL high-pass filter consists of a 470 Ω resistor and a 600 mH coil. The output is taken across the coil. The circuit's critical frequency is

A)

125 Hz

B)

564 Hz

C)

1,250 Hz

D)

5,644 Hz

Correct Answer : 125 Hz

24 .

In an RC low-pass filter, the output voltage is taken across the resistor and the output lags the input voltage.

A)

True

B)

False

C)

Can Not Say

D)

None of the above

Correct Answer : False

25 .

In a certain low-pass filter, fc = 3.5 kHz. If the input voltage is a 6 V sine wave with a dc level of 10 V, what is the output voltage magnitude?

A)

0 V

B)

5.97 V

C)

6 V

D)

597 mV

Correct Answer : 5.97 V

26 .

In an RL low-pass filter, the output voltage is taken across the inductor and the output lags the input.

A)

True

B)

False

C)

Can Not Say

D)

None of the above

Correct Answer : False

27 .

Which type of passive filter is commonly used in radio receivers to reject unwanted signals?

A)

Low-pass filter

B)

Band-pass filter

C)

High-pass filter

D)

Notch filter

Correct Answer : Notch filter

Explanation : Notch filters, or band-stop filters, are frequently used in radio receivers to reject unwanted signals at specific frequencies. By attenuating signals at these frequencies, notch filters help eliminate interference from nearby stations or other sources, ensuring a cleaner and more reliable reception.

28 .

Which component in a passive filter is responsible for storing and releasing energy?

A)

Resistor

B)

Inductor

C)

Capacitor

D)

Transformer

Correct Answer : Capacitor

Explanation : In a passive filter, a capacitor is responsible for storing and releasing electrical energy. It consists of two conductive plates separated by an insulating material, known as the dielectri3. When voltage is applied, the capacitor charges, storing energy in the electric field between the plates.

29 .

What is the purpose of a notch filter?

A)

To amplify all frequencies equally

B)

To attenuate both high and low frequencies

C)

To separate high-frequency components from a signal

D)

To eliminate a specific narrow frequency band from a signal

Correct Answer : To eliminate a specific narrow frequency band from a signal

Explanation : A notch filter, also known as a band-stop filter, is designed to attenuate or completely eliminate a specific narrow frequency band from a signal. It is often used to remove unwanted interference or noise at a particular frequency while allowing other frequencies to pass through.

30 .

In a certain parallel resonant band-pass filter, the resonant frequency is 14 kHz. If the bandwidth is 4 kHz, the lower frequency is

A)

7 kHz

B)

10 kHz

C)

12 kHz

D)

Can't be determined

Correct Answer : 12 kHz

31 .

An RC high-pass filter consists of an 820 Ω resistor. What is the value of C so that Xc is ten times less than Rat an input frequency of 12 kHz?

A)

0.161 µF

B)

81 µF

C)

161 µF

D)

220 µF

Correct Answer : 0.161 µF

32 .

In an RL high-pass filter, the output is taken across the inductor and the output leads the input.

A)

True

B)

False

C)

Can Not Say

D)

None of the above

Correct Answer : True

33 .

At a certain frequency, the output voltage of a filter is 6 V and the input is 12 V. The voltage ratio in decibels is

A)

6.02 dB

B)

-6.02 dB

C)

12.04 dB

D)

-12.04 dB

Correct Answer : -6.02 dB

34 .

The output voltage is 63.3% of its maximum at the critical frequencies.

A)

True

B)

False

C)

Can Not Say

D)

None of the above

Correct Answer : False

35 .

An RC low-pass filter consists of a 120 Ω resistor and a 0.002 µF capacitor. The output is taken across the capacitor. The circuit's critical frequency is

A)

60 kHz

B)

331 kHz

C)

333 kHz

D)

633 kHz

Correct Answer : 633 kHz

36 .

A parallel resonant band-pass filter consists of a 90 Ω resistor in series with a parallel network made up of a 60 mH coil and a 0.02 µF capacitor. The output is taken across the capacitor/coil. The coil winding has a resistance of 20 Ω. What is the center frequency of the filter?

A)

459 Hz

B)

999 Hz

C)

2,176 Hz

D)

4,591 Hz

Correct Answer : 4,591 Hz

37 .

A parallel resonant band-pass filter consists of a 6.8 Ω resistor in series with a parallel network made up of an 8 µH coil and a 120 pF capacitor. The output is taken across the capacitor/coil. Assume RW = 0 Ω. What is the center frequency of the filter?

A)

5.03 MHz

B)

5.14 MHz

C)

503 kHz

D)

514 kHz

Correct Answer : 5.14 MHz

38 .

Which type of passive filter is used to separate audio frequency bands in a speaker system

A)

Low-pass filter

B)

High-pass filter

C)

Band-pass filter

D)

Notch filter

Correct Answer : Band-pass filter

Explanation : A band-pass filter is employed to separate specific frequency bands from a complex signal. In speaker systems, band-pass filters are commonly used to separate audio frequency bands and direct them to the appropriate drivers, ensuring each driver receives the frequency range it is designed to reproduce.

39 .

What is the purpose of a low-pass filter?

A)

To amplify all frequencies equally

B)

To eliminate all frequencies except for the cutoff frequency

C)

To allow high frequencies to pass through while attenuating low frequencies

D)

To allow low frequencies to pass through while attenuating high frequencies

Correct Answer : To allow low frequencies to pass through while attenuating high frequencies

Explanation : A low-pass filter is designed to allow low-frequency components of a signal to pass through while attenuating high-frequency components. It effectively “filters out” the higher frequencies beyond the cutoff frequency, allowing only the lower frequencies to be present in the output signal.

40 .

Typical value of filter capacitor for a 50 Hz rectifier?

A)

50 Î¼F

B)

100 Î¼F

C)

100 pF

D)

1000 pF

Correct Answer : 50 Î¼F