28/07/2020 Noise Management and Control - - Unit 7 - WEEK 6
https://onlinecourses.nptel.ac.in/noc19_me72/unit?unit=51&assessment=127 1/3
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Course outline
How to access the portal WEEK 1 WEEK 2 WEEK 3 WEEK 4 WEEK 5
WEEK 6 Lecture 31:
Interference of 1-D spherically propagating sound waves-I (unit?
unit=51&lesson=52) Lecture 32:
Interference of 1-D spherically propagating sound waves-II (unit?
unit=51&lesson=53)
Due on 2019-09-11, 23:59 IST.
1 point 1)
1 point 2)
1 point 3)
Assignment 06
The due date for submitting this assignment has passed.
As per our records you have not submitted this assignment.
Which part of human ear converts sound vibrations into electrical signals?
Hammer Stirrup
Tympanic membrane Cochlea
No, the answer is incorrect.
Score: 0
Accepted Answers:
Cochlea
_______ microphones are useful for measuring noise close to airplane wings.
Pressure Free field
Random incidence Diffusive field
No, the answer is incorrect.
Score: 0
Accepted Answers:
Pressure
In carbon microphones, a variation in which of the following parameter was correlated to find out sound pressure level (SPL)?
Inductance.
28/07/2020 Noise Management and Control - - Unit 7 - WEEK 6
https://onlinecourses.nptel.ac.in/noc19_me72/unit?unit=51&assessment=127 2/3
WEEK 7 WEEK 8 WEEK 9 WEEK 10 WEEK 11 WEEK 12
Lecture 33:
Noise sources and introduction to microphones (unit?
unit=51&lesson=54) Lecture 34:
Classification of microphones-I (unit?
unit=51&lesson=55) Lecture 35:
Classification of microphones-II (unit?
unit=51&lesson=56) Lecture 36:
Classification of microphones-III (unit?
unit=51&lesson=57) Quiz :
Assignment 06 (assessment?
name=127) Feedback for Week 6 (unit?
unit=51&lesson=135)
1 point 4)
1 point 5)
1 point 6)
1 point 7)
Resistance.
Capacitance.
None of the options are correct.
No, the answer is incorrect.
Score: 0
Accepted Answers:
Resistance.
Two waves can add constructively or destructively. This phenomenon is termed as:
Reflection.
Refraction.
Diffraction.
Interference.
No, the answer is incorrect.
Score: 0
Accepted Answers:
Interference.
Variation in capacitance is used to measure sound pressure level in _________.
Carbon microphones.
Electrostatic microphones.
Fiber optics microphones.
Piezoelectric microphones.
No, the answer is incorrect.
Score: 0
Accepted Answers:
Electrostatic microphones.
What is the advantage of electret microphones over DC biased capacitor microphones?
Electret microphones permanently store charge across condenser plates. So there is no requirement of external power supply.
Electret microphones use graphite particles so that they can produce high level audio signals from low DC voltage.
Electret microphones use piezoelectric materials so that they can be used in high stress situations.
Electret microphones use transistor valves which require less power.
No, the answer is incorrect.
Score: 0
Accepted Answers:
Electret microphones permanently store charge across condenser plates. So there is no requirement of external power supply.
Which one of the following options is true regarding a 1-3 piezoelectric microphones?
In 1-3 piezoelectric microphones, voltage is measured perpendicular to the direction in which the stress is applied.
In 1-3 piezoelectric microphones, voltage is measured in the direction of applied stress.
In 1-3 piezoelectric microphones, moving coil is displaced in the direction of applied stress.
In 1-3 piezoelectric microphones, moving coil is displaced perpendicular to the direction in which the stress is applied.
No, the answer is incorrect.
Score: 0
Accepted Answers:
28/07/2020 Noise Management and Control - - Unit 7 - WEEK 6
https://onlinecourses.nptel.ac.in/noc19_me72/unit?unit=51&assessment=127 3/3
1 point 8)
1 point 9)
In 1-3 piezoelectric microphones, voltage is measured perpendicular to the direction in which the stress is applied.
Microphone which senses all frequencies from every direction with same sensitivity is called ______ .
Omni directional.
Cardioid.
Sub cardioid.
Hyper cardioid.
No, the answer is incorrect.
Score: 0
Accepted Answers:
Omni directional.
What is the preferred shape of frequency response curve for a good microphone?
It should be linear in the band width of interest.
It should be linear with slope zero in the band width of interest.
It should be non linear in the band width of interest.
It should be linear with negative slope in the band width of interest.
No, the answer is incorrect.
Score: 0
Accepted Answers:
It should be linear with slope zero in the band width of interest.
