# MCQ in Acoustics Part 3 | ECE Board Exam

(Last Updated On: June 20, 2020) This is the Multiples Choice Questions Part 3 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

• MCQ in Acoustics Terms and Definition
• MCQ in Frequency Range
• MCQ in Sound Pressure Level
• MCQ in Sound Intensity
• MCQ in Loudness Level
• MCQ in Pitch and Frequency
• MCQ in Internal and Octave
• MCQ in Sound Distortion
• MCQ in Room Acoustics
• MCQ in Electro-Acoustics Transducers
Watch Audio MCQ in Acoustics

#### Continue Practice Exam Test Questions Part 3 of the Series

101. What do you call the speed of sound in the study of acoustics?

a. Rhythm

b. Tempo

c. Pitch

d. Frequency

Solution:

102. The term that describes the highness or lowness of a sound in the study of acoustics is called a

a. Tempo

b. Pitch

c. Volume

d. Bass

Solution:

103. The method of measuring absorption coefficient of sound which considers all angles of incidence is called

a. Distance method

b. Bounce back to back method

c. Impedance method

d. Reverberation chamber method

Solution:

104. The tendency of a sound energy to spread

a. Rarefaction

b. Reflection

c. Refraction

d. Diffraction

Solution:

105. _____ is the advantage rate of transmission of sound energy in a given direction through a cross-sectional area of 1 sq m at right angles to the direction of propagation.

a. Sound pressure

b. Sound intensity

c. Pressure variation

d. Loudness

Solution:

106. The unit of pitch

a. Decibel

b. Phon

c. mel

d. Sone

Solution:

107. a large speaker having a large diameter(15 cm and above)

a. coaxial speaker

b. woofer

c. tweeter

d. triaxial speaker

Solution:

108. A method of expressing the amplitude of a complex non-periodic signal such as speech

a. Frequency

b. Wavelength

c. Volume

d. Pitch

Solution:

109. The lowest frequency produced by an instrument

a. Harmonic

b. Fundamental

c. Midrange

d. 0 Hz

Solution:

110. Sound intensity is given as

a. df/dp

b. dE/dP

c. dA/dP

d. dP/dA

Solution:

111. Which of the following is considered the most commonly used measurable components of sound?

a. its temperature

b. particle displacement

c. softness

d. source

Solution:

112. _____ is the transmission of sound from one room to an adjacent room thru common walls, floors, or ceilings.

a. Reverberation

b. Refraction

c. Flanking transmission

d. Reflection

Solution:

113. The midrange frequency range of sound is from

a. 256 to 2048 Hz

b. 2048 to 4096 Hz

c. 512 to 2048 Hz

d. 16 to 64 Hz

Solution:

114. Designates the sensation of low or high in the sense of the bass and treble

a. Frequency

b. Intensity

c. Pitch

d. SPL

Solution:

115. Speaker is a device that

a. Converts current variations into sound waves

b. None of these

c. Converts electrical energy to mechanical energy

d. Converts sound waves into current and voltage

Solution:

116. One-hundred twenty microbars of pressure variation is equal to

a. 120 dBSPL

b. 115.56 dBSPL

c. 41.58 dBSPL

d. 57.78 dBSPL

Solution:

117. An instrument for recording waveforms of audio frequency

a. Oscilloscope

b. Phonoscope

d. Audioscope

Solution:

118. In the study of acoustics, the velocity of sound is dependent to one of the following

a. Temperature

b. Loudness

c. Source of sound

d. Properties of the medium

Solution:

119. How much bigger in storage capacity has digital video disk (DVD) have over the conventional compact disk (CD)?

a. Around triple

b. Around 15 times

c. Around twice

d. Around 5 times

Solution:

120. A sound intensity that could cause painful sensation in a human ear

a. Threshold of sense

b. Threshold of pain

c. Hearing threshold

d. Sensation intensity

Solution:

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

a. 12 W

b. 0.12 W

c. 0.012 W

d. 1.2 W

Solution:

122. Noise reduction system for film sound in movie

a. Dolby

b. dBx

c. dBa

d. dBk

Solution:

123. 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

Solution:

124. A unit of noisiness related to the perceived noise level

a. Noy

b. Sone

c. dB

d. Mel

Solution:

125. Required time for and sound to decay to 60 dB

a. Echo time

b. Delay time

c. Reverberation time

d. Transient time

Solution:

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

a. 1/2

b. 1/3

c. 2/3

d. 1/4

Solution:

127. 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:

128. 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. Doppler effect

c. Haas effect

Solution:

129. 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:

130. The minimum sound intensity that can be heard

a. Threshold of feeling

b. Threshold of pain

c. Threshold of sensation

d. Threshold of hearing

Solution:

131. The ____ of a sound is a subjective effect which is a function of the ear and brain.

a. Pitch

b. Frequency

c. Timbre

d. Loudness

Solution:

132. A term which is subjective but independent mainly on frequency and also affected by intensity

a. Pitch

b. Frequency

c. Timbre

d. Loudness

Solution:

133. A sound 0f 18 kHz frequency has a wavelength of

a. 18.3 mm

b. 183 mm

c. 250 mels

d. 1.86 mels

Solution:

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

a. 1000 mels

b. 10000 mels

c. 250 mels

d. 800 mels

Solution:

135. What is the velocity of sound in dry air for a temperature change of 45 degrees Celsius?

a. 249.19 m/s

b. 331.45 m/s

c. 357.73 m/s

d. 358.77 m/s

Solution:

136. What us the resonant frequency of a Helmholtz resonator whose volume is 2.5 cu m with neck radius of 8 cm?

a. 13 Hz

b. 11 Hz

c. 15 Hz

d. 14 Hz

Solution:

137. 40 phons is equivalent to how many sones?

a. 0 sone

b. 1 sone

c. 0.5 sone

d. 16 sones

Solution:

138. 80 phons + 80 phons =

a. 83 phons

b. 160 phons

c. 90 phons

d. 86 phons

Solution:

139. An early reflection of sound

a. Echo

b. Reverberation

c. Pure sound

d. Jitter

Solution:

140. 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

Solution:

141. The term used for the deafness of higher frequencies due to old age

a. Ear deafness

b. Cortial deafness

c. Tinnitus

d. Presbycusis

Solution:

142. What is the dBSPL of an auditorium with contemporary music?

a. 95-100 dB

b. 40-50 dB

c. 50-60 dB

d. 70-80 dB

Solution:

143. What principle is used by a carbon type micro phone?

a. Variable capacitance

b. Variable resistance

c. Variable inductance

d. Piezoelectric effect

Solution:

144. Pressure is measured in term of Pascal, microbar or

a. Newtons

b. Newtons per meter

c. Newtons per meter squared

d. Pascal per meter squared

Solution:

145. How much power can a human voice possible produce

a. 100 milliwatts

b. 1 watt

c. 10 watts

d. 1 milliwatt

Solution:

146. What is the increase in sound pressure level if the pressure is doubled?

a. Increase by 6 dB

b. Increase by 3 dB

c. Decrease by 6 dB

d. Decrease by 3 dB

Solution:

147. The frequency limits of audio frequency is

a. 300 – 3000 Hz

b. 20 Hz – 20 kHz

c. 3 – 3 kHz

d. 40 – 40 kHz

Solution:

148. A device that converts sound pressure into electrical energy

a. Microphone

d. Speaker

Solution:

149. An agreed set of empirical curves relating octave-band sound pressure level to the center frequency of the octave bands

a. C-message weighting curve

b. Psophometric curve

c. Noise rating curve

d. F1A weighting curves

Solution:

150. Pure tone of sound used as standard on testing

a. 1 kHz

b. 300 – 3400 Hz

c. 100 Hz

d. 800 Hz

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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