# Frequency Filters – 1 MCQ’s

This set of Analog Electronic Circuits Multiple Choice Questions & Answers (MCQs) focuses on “Frequency Filters – 1″.

1. In a low pass filter as below, find the cut-off frequency for the following circuit.

Given that R1=20kΩ, R2=25kΩ, C1=10nF.

a) 640 kHz

b) 636 Hz

c) 5.5 kHz

d) 200 Hz

2. Given that the maximum gain of a low pass filter using op-amp is 5.5 and the resistor R1 = 10kΩ, find the value of R2.

a) 220kΩ

b) 55kΩ

c) 50Ω

d) -55kΩ

3. For the circuit, calculate the phase shift.

It is given that R1=20kΩ, C1=2nF, R2=22kΩ, and input signal is 2sin6π103t.

a) 233.04°

b) 230.32°

c) 333.04°

d) 129.67°

4. Which is not a difference between active and passive filter?

a) A passive filter does not use op-amp while an active filter uses an op-amp

b) A passive filter can’t use an inductor while an active filter can

c) A passive filter performs only filtering while an active filter amplifies too

d) A passive filter is used at audio frequency and an active at radio frequency

5. When the input frequency is equal to the cutoff frequency, how much is the phase shift in the output?

a) 180°

b) -135°

c) -45°

d) 135°

6. What is the frequency response of the filter shown below?

Given R1C1=R2C2.

b)

7. For a low pass filter of non-inverting type, the cutoff frequency is 2kHz and the input frequency is 4kHz. Find the phase shift in output.

a) 117°

b) -117°

c) 243°

d) -63°

8. Given the following circuit, find the maximum gain.

a) 1+R2/R1

b) –R3/R2

c) 1+R3/R2

d) 1+ R1.R3/2

9. A filter is provided of order 3, find the roll-off rate.

a) 6 dB/decade

b) 60 dB/octave

c) 60 dB/decade

d) 3 dB/decade

10. Consider the circuit below and find its cut-off frequency.

R1=10kΩ, R2=20kΩ, R3=30kΩ, C1=2nF, C2=4nF, R4=15kΩ.

a) 4.6 kHz

b) 6.2 kHz

c) 5.5 kHz

d) 4.2 kHz