# MCQ in Acoustics Part 2 | ECE Board Exam

(Last Updated On: June 20, 2020) This is the Multiples Choice Questions Part 2 of the Series in Acoustics as one of the Communications Engineering topic. In Preparation for the ECE Board Exam make sure to expose yourself and familiarize in each and every questions compiled here taken from various sources including but not limited to past Board Examination Questions in Electronic System and Technologies, Communications Books, Journals and other Communications References.

#### 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
Watch Audio MCQ in Acoustics

#### Continue Practice Exam Test Questions Part 2 of the Series

51. What is the dB SPL of a voice paging in an office?

a. 90

b. 65

c. 55-60

d. 80-85

Solution:

52. What is the dB SPL of an auditorium with contemporary music?

a. 80-95

b. 85-90

c. 95-100

d. 100-105

Solution:

53. What is the church dB SPL with speech reinforcement only?

a. 90

b. 80-85

c. 85-90

d. 90-95

Solution:

54. Intensity can also be called as

a. Volume

b. Loudness

c. Sharpness

d. Strength

Solution:

55. The loudness of a sound depends upon the energy of motion imparted to ________ molecules of the medium transmitting the sound.

a. Transmitting

b. Running

c. Moving

d. Vibrating

Solution:

56. _________ is affected by the distance between the listener and the source of the sound and its intensity varies inversely with the square of its distance.

a. Volume

b. Bass

c. Treble

d. Loudness

Solution:

57. If the distance between the listener and the source of the sound is doubled, the intensity is reduced to

a. ½

b. 1/3

c. 2/3

d. 1/4

Solution:

58. If the distance between the listener and the source of the sound is decreased to ½ tye original amount, the intensity of the sound would be

a. 2 times as great

b. 3 times as great

c. 4 times as great

d. 5 times as great

Solution:

59. At a sensation level of 40 dB, 1000 Hz tone is

a. 1000 mels

b. 500 mels

c. 2000 mels

d. 100 mels

Solution:

60. If the sound waves are converted to electrical waves by a microphone, what is the frequency of the electric current?

a. 3 – 30 MHz

b. 25 – 8000 Hz

c. 4 – 40 Hz

d. 30 – 3000 Hz

Solution:

61. For a music lover concert “A” is 440 Hz. If a musical note one octave higher were played, it would be _______ that frequency.

a. One – half

b. One-fourth

c. Double

d. Triple

Solution:

62. In a 220 Hz, if a note was played one octave lower, it would be ______.

a. 22 Hz

b. 27.5 Hz

c. 440 Hz

d. 110 Hz

Solution:

63. Much of music is generally referred to in

a. Harmonics

b. Good hearing

c. Fidelity

d. Octaves

Solution:

64. _________ is an undesired change in wave form as the signal passes through a device.

a. Noise

b. Vibration

c. Distortion

d. Harmonics

Solution:

65. Distortion enhances intelligibly when an ________ is added.

a. Equalizer

b. Igniter

c. Exciter

d. Emulsifier

Solution:

66. A class of signal processors.

a. Amplifiers

b. Equalizers

c. Microprocessors

d. Exciters

Solution:

67. Half construction and internal finishes affect the final sound quality ________.

a. poorly

b. mildly

c. significantly

Solution:

68. Positioning a loudspeaker near a wall can dramatically alter its frequency response in two distinct ways namely;

a. Gump and dump

b. Hump and notch

Solution:

69. The acoustics of most auditoria are very ________ when the room is full compared to the empty condition.

a. Different

b. Similar

c. Good

Solution:

70. A _________ converts acoustical energy.

a. Electro-acoustic

b. Microphone transducer

c. Microphone

d. Electric Microphone

Solution:

71. All microphone have two basic components namely, ­­___________.

a. Wired and body

b. Ceramic and crystal

c. Diaphragm and generating element

d. Coil and magnet

Solution:

72. The kinds of generating elements are __________.

a. Expense and fidelity

b. Complexity and ruggedness

c. Longevity

d. All of these

Solution:

73. When the average absorption is greater than 0.2, __________ formula is used to compute the actual reverberation time.

a. Sabine

b. Stephen and Bate

c. Norris-Eyring

d. Notch

Solution:

74. At room temperature, what is the velocity of sound in meters/seconds?

a. 348.03 cm/s

b. 980 cm/s

c. 980 m/s

d. 341.8 m/s

Solution:

75. Calculate the velocity of sound in ft./sec. if the temperature is 149°C?

a. 1530.03 ft/sec

b. 1320 ft/sec

c. 1357.03 ft/sec

d. 1920.345 ft/sec

Solution:

76. The wavelength of a sound of 20 kHz frequency is

a. 16.5 m

b. 16.5 cm

c. 16.5 mm

d. 16.5 um

Solution:

77. The radio of frequencies is termed

a. Octave

b. Interval

c. Harmonics

Solution:

78. What is the increase in sound pressure level in dB, if the pressure is doubled?

a. 2 dB

b. 3 dB

c. 6 dB

d. 4 dB

Solution:

79. A term which is subjected but dependent mainly on frequency and also affected by intensity,

a. Timbre

b. Quality

c. Frequency

d. Pitch

Solution:

80. An effect that occurs in the ear where a louder sound can reduce or even stop the nerve voltage generated by a weaker sound.

a. Piezoelectric effect

b. Skin effect

c. Lasing

Solution:

81. For computation of ideal reverberation time, which formula is applicable?

a. Sabine

b. Stephen and Bate

c. Norris-Eyring

d. Notch

Solution:

82. The __________ of the sound is a subjective effect which is a function of the ear and brain.

a. Pitch

b. Frequency

c. Timbre

d. Loudness

Solution:

83. Define as the time taken from the intensity of sound energy in the room to drop to one millionth of its initial value.

a. Reverberation time

b. Transit time

c. Decaying time

d. Response time

Solution:

84. __________ is the sound energy per unit area at right angles of the propagation direction, per unit time.

a. Loudness

b. Coherence

c. Sound stress

d. Sound intensity

Solution:

85. One octave above 600 Hz is

a. 601 Hz

b. 800 Hz

c. 1400 Hz

d. 1200 Hz

Solution:

86. A car horn outdoors produces a sound intensity level of 90 dB at 10 m away. At this distance, what is the sound power in watt?

a. 0.63

b. 1.26

c. 0.315

d. 0.56 x 10^-6

Solution:

87. The unit of loudness level

a. Sone

b. dB

c. Mel

d. Phon

Solution:

88. Consist of a rapid succession of noticeable echoes.

a. Rarefaction

b. Refraction

c. Reflection

d. Flutter echo

Solution:

89. Laid the foundations of acoustic theory of buildings.

a. Charles H. Townes

b. W.C Sabine

c. A. Javin

d. Stephen and Bate

Solution:

90. An aural sensation by pressure variations in the air which are always produced by some source of vibrations.

a. Music

b. Sound

c. Disturbance

d. Speech

Solution:

91. Considered to be the threshold of hearing.

a. 10^-12 W/cm^2

b. 10^-16 W/m^2

c. 10^-13 W/m^2

d. 10^-12 W/m^2

Solution:

92. The average absorption for a person is

a. 5.7 units

b. 4.7 units

c. 6.7 units

d. 3.7 units

Solution:

93. The number of vibration or pressure fluctuations per seconds.

a. Frequency

b. Timbre

c. Quality

d. Pitch

Solution:

94. Defined as the average rate of transmission of sound energy in a given direction through a cross-sectional area of 1 m^2 at right angles to the direction.

a. Sound pressure

b. Loudness

c. Sound intensity

d. Pressure variation

Solution:

95. What is the sound pressure level (SPL) of a sound having a RMS pressure of 200 N/m^2?

a. 150 dB

b. 140 dB

c. 170 dB

d. 160 dB

Solution:

96. The minimum sound intensity that can be heard is termed

a. Threshold of feeling

b. Threshold of pain

c. Threshold of sensation

d. Threshold of hearing

Solution:

97. What is the intensity of the sound whose RMS pressure is 200 N/m^2?

a. 96.9 W/m^2

b. 97.9 W/m^2

c. 95.9 W/m^2

d. 94.9 W/m^2

Solution:

98. The unit of pitch.

a. sone

b. pitch

c. dB

d. Mel

Solution:

99. What is the increase in sound pressure level in dB, if the intensity is doubled?

a. 2 dB

b. 3 dB

c. 4 dB

d. 6 dB

Solution:

100. The velocity of sound is considered to be constant at ________ for the purpose of acoustics.

a. 300 m/s

b. 330 mm/s

c. 330 µm/s

d. 330 cm/s

Solution:

#### Questions and Answers in Acoustics Series

Following is the list of multiple choice questions in this brand new series:

MCQ in Acoustics
PART 1: MCQ from Number 1 – 50                        Answer key: PART 1
PART 2: MCQ from Number 51 – 100                   Answer key: PART 2
PART 3: MCQ from Number 101 – 150                 Answer key: PART 3
PART 4: MCQ from Number 151 – 200                 Answer key: included

### Complete List of MCQ in Communications Engineering per topic

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