All-Pass Filter MCQ [Free PDF] – Objective Question Answer for All-Pass Filter Quiz

1. How many types of band elimination filters are present

A. Three
B. Two
C. Four
D. None of the mentioned

Answer: B

Band-reject filters are also called as band elimination filters. They are classified into two types.

i) Wide band-reject filter and
ii) Narrow band-reject filter.


3. A narrow band-reject filter is commonly called as

A. Notch filter
B. Band step filter
C. Delay filter
D. All of the mentioned

Answer: A

A narrow band-reject filter is also called a notch filter because of its higher quality factor, Q (>10).


4. Find the expression for notch-out frequency?

A. fN = 2πRC
B. fN = 2π/RC
C. fN = 1/2π×√(R/C.
D. fN = 1/2πRC

Answer: D

The notch-out frequency is the frequency at which maximum attenuation occurs: it is given by fN =1/2πRC.


5. The quality factor of passive twin T-network is increased by using

A. Inverting amplifier
B. Non-inverting amplifier
C. Voltage follower
D. Differential amplifier

Answer: C

The passive twin T-network has a selectively low figure of merit. The Q of the network can be increased significantly if it is used with the voltage follower.


6. Find out the application in which a narrow band-reject filter can be used?

A. Embedded system
B. Biomedical instrument
C. Digital computer
D. None of the mentioned

Answer: B

Notch filters or narrow band-reject filters are used in biomedical instruments for eliminating undesired frequencies.


7. Find the application of the area where all-pass filters are used?

A. Cathode ray oscilloscope
B. Television
C. Telephone wire
D. None of the mentioned

Answer: C

When signals are transmitted in transmission lines like telephone wires, they undergo a phase change, all-pass filters are used to compensate for these phase changes.


8. Determine the output voltage for all the all-pass filters and express it in complex form?

A. VO =Vin/ [(1-j2πfRC. /(1+ j2πfRC.].
B. VO =Vin× [(1+j2πfRC. /(1- j2πfRC.].
C. VO =Vin ×[(1- j2πfRC. /(1+ j2πfRC.].
D. None of the mentioned

Answer: C
The output voltage of the all-pass filter is given as

VO =Vin× [(1-j2πfRC. /(1+j2πfRC.] .


9. Determine the input frequency for the all-pass filter with a phase angle of 62o. Consider the value of resistor and capacitor are 3.3kΩ and 4.7µF.

A. Input frequency= -7.65Hz
B. Input frequency= -6.77Hz
C. Input frequency= -3.89Hz
D. Input frequency= -9.65Hz

Answer: D

The phase angle is given as

Φ = -2tan-1×(2πfRC.

=> f=-tanΦ/4πRC


= -1.88/0.1948 =-9.65Hz.


10. Determine the angle for the given circuit diagram, if the frequency of the input signal is 1khz

Determine the angle for given circuit diagram, if the frequency of input signal is 1khz
A. -45o
B. -180o
C. -270o
D. -90o

Answer: D

Phase angle Φ


= -2tan-1×(2π×1kHz×16kΩ×0.01µF)

= -2tan-1×(1.0048)=-90o.

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