Online Questions and Answers Topic Outline
- MCQs in Acoustics Terms and Definition
- MCQs in Frequency Range
- MCQs in Sound Pressure Level
- MCQs in Sound Intensity
- MCQs in Loudness Level
- MCQs in Pitch and Frequency
- MCQs in Internal and Octave
- MCQs in Sound Distortion
- MCQs in Room Acoustics
- MCQs in Electro-Acoustics Transducers
MCQs in Acoustics Series
Following is the list of multiple choice questions in this brand new series:
Start Practice Exam Test Questions Part I of the Series
1. An instrument designed to measure a frequency-weighted value of the sound pressure level.
- a. Sound-level meter
- b. Transducer
- c. Sound pressure meter
- d. Sound analyzer
2. A unit of noisiness related to the perceived noise level
- a. Noy
- b. Sone
- c. dB
- d. phone
3. An agreed set of empirical curves relating octave-band osund pressure level to the center frequency of the octave bands
- a. C-message weighting curves
- b. Psophometric weighting curves
- c. Noise rating curves
- d. F1A weighting curves
4. The frequency of free vibration
- a. Resonant frequency
- b. Natural frequency
- c. Center frequency
- d. Normal frequency
5. The transmission of sound from one room to an adjacent room, via common walls, floors or ceilings.
- a. Flanking transmission
- b. Refraction
- c. Reflection
- d. Reverberation
6. A measure of threshold hearing, expressed in decibels relative to a specifoed standard of normal hearing.
- a. Hearing loss
- b. Sensation level
- c. Hearing level
- d. Sound pressure level
7. A certain machine with a slightly out-of-balance motor rotating at 1800/min is fixed on a perfectly elastic mount with a static compression of 2.50 mm. Calculate the resonant frequency of mount.
- a. 10 Hz
- b. 20 Hz
- c. 30 Hz
- d. 40 Hz
8. Calculate the lowest resonant frequency for a brick partition 120 mm thick, 4m by 2min area with longitudinal wave velocity of 2350 m/s. (Assume that it is supported at its edges.)
- a. 10 Hz
- b. 20 Hz
- c. 30 Hz
- d. 40 Hz
9. Velocity of sound in air.
- a. 300 m/s
- b. 330 m/s
- c. 1130 m/s
- d. 344 m/s
10. What is the expected critical frequency for a 120 mm thick brick wall? Assume a longitudinal wave velocity in brick of 2350 m/s and that the velocity of sound in air is 330 m/s.
- a. 114.5 Hz
- b. 214.5 Hz
- c. 314.5 Hz
- d. 414.5 Hz
11. The sound power level of a certain jet plane flying at a height of 1km is 160 dB (re10-12W). Find the maximum sound pressure level on the ground directly below the flight path assuming that the aircraft radiates sound equally in all directions.
- a. 59.1 dB
- b. 69.1 dB
- c. 79.1 dB
- d. 89.1 dB
12. Speaker is a device that
- a. Converts sound waves into current and voltage
- b. Converts current variations into sound waves
- c. Converts elctrical energy to mechanical energy
- d. Converts elctrical energy to electromagnetic energy
13. Which type of microphone operates on the principle that the electrical resistance of carbon granules varies as the pressure on the granules vary?
- a. Dynamic
- b. Crystal
- c. Carbon
- d. Ribbon-type
14. Bass response is
- a. Maximum high frequency response
- b. Emphasizing the high audio frequency
- c. Bypassing high audio frequencies
- d. Bypassing low audio frequencies
15. Pure tone of sound used as standard on testing
- a. 1 Hz
- b. 10 Hz
- c. 100 Hz
- d. 1000 Hz
16. ___________ is early reflection of sound.
- a. Echo
- b. Reverberation
- c. Pure sound
- d. Intelligible sound
17. Noise reduction system used for film sound in movie.
- a. Dolby
- b. dBa
- c. dBx
- d. dBk
18. What is the sound energy per unit area at right angles to the propagation direction per unit time?
- a. Loudness
- b. Coherence
- c. Sound pressure
- d. Sound intensity
19. ________ is the unit of loudness level of a sound.
- a. Sone
- b. Decibel
- c. Mel
- d. Phon
20. ____________ is the average rate of transmission of sound energy in a given direction through a cross-section area of 1 sqm at right angles to the direction.
- a. Sound pressure
- b. Loudness
- c. Sound intensity
- d. Pressure variation
21. What is the unit of pitch?
- a. Sone
- b. Phon
- c. Decibel
- d. Mel
22. A measure of the intensity of sound in comparison to another sound intensity.
- a. Phon
- b. Decibel
- c. Pascal
- d. Watts
23. Sound wave has two main characteristics which are
- a. Highness and loudness
- b. Tone and loudness
- c. Pitch and loudness
- d. Rarefraction and compression
24. Which type of microphone operated by electromagnetic induction that generates an output signal voltage?
- a. Carbon
- b. Dynamic
- c. Crystal
- d. Condenser
25. The exciter lamp in the optical sound part of a film projector draws 5 A at 10 V. How much power in watts is this light consuming?
- a. 10 watts
- b. 20 watts
- c. 40 watts
- d. 50 watts
26. Assume the speed of sound is 1,130 ft/s. What frequency has a wavelength of 1 foot, 1.5 inches?
- a. 500 Hz
- b. 1000 Hz
- c. 1500 Hz
- d. 2000 Hz
27. The wire must bring 100 average watts to a 4 ohms loudspeaker must safely carry what rms current?
- a. 2 A
- b. 4 A
- c. 5 A
- d. 6 A
28. A church has an internal volume of 90.05 ft3 (2550 m3). When it contains customary sabine sof absorption (186 metric sabines), what will be its reverberation time in seconds.
- a. 2.0
- b. 2.2
- c. 2.5
- d. 3.0
29. If the RMs sound pressure is 5lb/ft2, what is the sound presure level?
- a. 7.6 dB
- b. 108 dB
- c. 88 dB
- d. 10 dB
30. Speed that is faster than speed of sound.
- a. Ultrasonic
- b. Supersonic
- c. Subsonic
- d. Transonic
31. Sound waves travel faster in water at a ______ speed.
- a. 12.4 miles/sec
- b. 5000 ft/sec
- c. 186,000 ft/sec
- d. 3141 ft/sec
32. What is the sound power from a motor car whose SPL at a distance of 7.5 m is 87 dB assuming that it radiates sound unifomly?
- a. 0.15 W
- b. 0.21 W
- c. 0.24 W
- d. 0.18 W
33. Crest-to-crest distance along the direction to wave travel.
- a. Compression
- b. Wavelength
- c. Period
- d. Sound wave
34. Sound intensity level is _________.
- a. 10 log I/Iref
- b. 10 log P/Pref
- c. 20 log I/Iref
- d. 30 log P/Pref
35. Sound pressure level is _________.
- a. 20 log P/ Pref
- b. 30 log P/ Pref
- c. 10 log P/ Pref
- d. 20 log I/Iref
36. The most important specification of loudspeakers and microphones.
- a. Frequency response
- b. Field strength
- c. Power density
- d. Gain
37. Lowest fequency produced by a musical instrument.
- a. Midrange
- b. Harmonic
- c. Reflection
- d. Refraction
38. Tendency of a sound energy to spread.
- a. Diffraction
- b. Rarefraction
- c. Reflection
- d. Refraction
39. When waves bend away from straight lines of travel, it is called _________.
- a. Reflection
- b. Diffraction
- c. Rarefraction
- d. Refraction
40. Required time for any sound to decay to 60 dB.
- a. Echo time
- b. Delay time
- c. Reverberation time
- d. Transient time
41. The intensity needed to produce an audible sound varies with __________.
- a. Frequency
- b. Noise
- c. Amplitude
- d. Tone
42. Sound that vibrates too high for the human ear to hear (over 20 kHz).
- a. Subsonic
- b. Transonic
- c. Ultrasonic
- d. Stereo
43. Which microphone will be damaged if exposed to high temperature above 52°C?
- a. Dynamic
- b. Crystal
- c. Ribbon
- d. Capacitor
44. A thin springy sheet of bakelite or metal that permits the voice coil in a dynamic loudspeaker to move back and forth salong the core of its magnet.
- a. Vibrator
- b. Diaphragm
- c. Hypex
- d. Spider
45. One hundred twenty µbars of pressure variation is equal to
- a. 120 dB SPL
- b. 57.78 dB SPL
- c. 115.56 dB SPL
- d. 41.58 dB SPL
46. The reverberation time of a 184.2 cubic meters broadcast studio is 0.84 sec. Find the absorption effect of the materials used in metric sabines.
- a. 35.3
- b. 10.96
- c. 379.8
- d. 109.6
47. What is the microphone characteristic that results in a boost in bass frequencies for close microphone spacing?
- a. Field effect
- b. P.A. effect
- c. Proximity effect
- d. Reverberation
48. What is the audio frequency range?
- a. 20 kHz to 20 MHz
- b. 0 Hz to 20 kHz
- c. 300 Hz to 400 Hz
- d. 20 Hz to 20 kHz
49. What is the bass frequency range?
- a. 2500 Hz to 5000 Hz
- b. 5000 Hz to 10 kHz
- c. 40 kHz to 160 kHz
- d. 10 Hz to 20 kHz
50. High frequency range of audio signals.
- a. 2500 Hz to 5000 Hz
- b. 5000 Hz to 10 kHz
- c. 10 kHz to 20 kHz
- d. 20000 Hz to 30 kHz
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What reference book do you use for Acoustics? thank you.
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