Questão 1
Questão
Sound amplification in the outer ear (auditory canal)is affected by:
Responda
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Sound speed
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Sound pressure
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Sound amplitude
Questão 2
Questão
Prolonged exposure to loud noise can cause permanent damage to:
Questão 3
Questão
The loss of elasticity (stiffening) of the tympanic membrane will result in:
Responda
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Increase of air conductivity
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Decrease of hearing threshold
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Decrease in the binaural effect
Questão 4
Questão
Sound intensity level (dB) and Loudness (phones) will have the same magnitude at the following frequency: (ref. the equal-loudness graph, Fig.1)
Questão 5
Questão
Refer to the equal-loudness curve above. At frequency of 4000 Hz the perceived sound is:
Responda
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Louder than at 1000 Hz
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The same as at 1000 Hz
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Softer than at 1000 Hz
Questão 6
Questão
Sound Intensity Level is proportional to the logarithm of the ratio of incoming to threshold intensity SIL = 10·Log (I/I0). If intensity is increased by a factor of 100, what is change in SIL?
Questão 7
Questão
The sound intensity level in a room is 20 dB. A TV produces additional intensity level of 60 dB. What is the sound intensity in the room now?
Questão 8
Questão
Match the physical (objective) with the corresponding psychophysical (subjective) properties of the sound: (hint: multiple connections are possible)
A) Frequency
B) Intensity
C) Acoustic Spectrum
Responda
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Frequency - Loudness
Intensity - Timbre
Acoustic Spectrum - Pitch
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Intensity - Pitch
Acoustic spectrum - Loudness
Frequency - Timbre
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Acoustic spectrum - Timbre
Intensity - Loudness
Frequency - Pitch
Questão 9
Questão
Sound frequency is:
Responda
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Psychophysical property (subjective)
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Physical property (objective)
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Sound is measured in wavelength, and light is measured in frequency
Questão 10
Questão
The fundamental harmonic (frequency f0) in a complex sound is characterized by:
Responda
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The lowest frequency and highest amplitude
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The highest frequency and lowest amplitude
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The highest frequency and highest amplitude
Questão 11
Questão
The speed of sound is calculated by the Newton-Laplace formula √ , where K is the stiffness coefficient, and ρ is the density of the material. If the density of the substance doubles, the speed of propagating sound wave will:
Responda
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Increase
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Decrease
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Depends on the frequency
Questão 12
Questão
What is the speed of sound in air?
Questão 13
Questão
Does absorption of sound and the corresponding penetration depth depend on the wavelength?
Responda
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No
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It does. There is less absorption at longer wavelengths, and they propagate deeper
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It does. There is less absorption at shorter wavelengths, and they propagate deeper
Questão 14
Questão
Is it possible for internal organs to generate sounds that propagate to the skin, and are audible?
Responda
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No
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Yes, organs produce sounds that propagate through the tissues and are audible at the skin
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No, organs generate sounds but the waves are absorbed by the tissues and are inaudible at the skin
Questão 15
Questão
Noise can be defined as:
Responda
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Intense sound with constant frequency
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Directed sound waves with low intensity and changing modulation
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Superposition of random sound vibrations, with frequency and amplitude constantly changing in time.
Questão 16
Questão
Damping oscillations are:
Questão 17
Questão
If the amplitude of a wave doubles (x2), what would happen to the period?
Responda
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It will double
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It will be halved
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There will be no change
Questão 18
Questão
which of the following mediums, sound waves cannot propagate?
Questão 19
Questão
Which of the following waves are NOT mechanical?
Responda
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Light
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Water waves
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Sound waves
Questão 20
Questão
A propagating sound wave transfers:
Responda
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Energy
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Matter
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Both, energy and matter
Questão 21
Questão
Which of the following factors has the most significant effect on the speed of propagation of sound waves?
Responda
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Elastic properties of the medium
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The size of the wave front
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The pressure in gaseous environment
Questão 22
Responda
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Mechanical waves
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Electromagnetic waves
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Gravitational waves
Questão 23
Questão
The speed of sound (in non-dispersive medium):
Responda
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Depends on the properties of the propagating medium
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Is always constant, independent of the medium
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Decreases as sound moves away from the its source
Questão 24
Questão
Human ear is most sensitive to frequencies (refer to equal-loudness curve):
Responda
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Below 1000 Hz
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From 2000 Hz to 5000 Hz
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Above 5000 Hz
Questão 25
Questão
What is the meaning of 0 dB?
Questão 26
Responda
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Physical (objective) property of sound
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Psychophysical (subjective) sound property
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Type of wood found in North America
Questão 27
Questão
The pitch of sound depends mostly on:
Responda
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Intensity of sound
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Sound pressure
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Sound frequency
Questão 28
Questão
Which of the following does NOT have relevance to the reflection/transmission of sound waves?
Responda
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The acoustic impedance of substances at the boundary
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The colors of substances near the boundary area
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The cross sectional area of the boundary surface
Questão 29
Questão
Timbre is related to:
Responda
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Harmonic overtones
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Wooden instruments
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Falling trees
Questão 30
Questão
Weber-Fechner law (in psychophysics) describes a logarithmic relationship between the intensity of a sound wave and….:
Questão 31
Questão
Intensity is defined as:
Responda
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Power per area
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Power per time
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Energy per time
Questão 32
Questão
When sound wave travels across two materials with similar acoustic impedance, at the boundary surface there will be:
Responda
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similar amounts of transmission and reflection
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more transmission and less reflection
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less transmission and more reflection
Questão 33
Questão
The acoustic impedance Z of a substance is defined as the product of:
Responda
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The density and the atomic number of the element: ρZ
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The density and the speed of sound: ρv
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The temperature and the speed of sound: tv
Questão 34
Questão
Why can’t we hear voices (speech) when submerged under water?
Responda
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Most of the sound is reflected at the air/water boundary
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Sound waves do not propagate under water
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Ear canals are clogged with water
Questão 35
Questão
What property of sound is measured in decibels (dB)?
Responda
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Wavelength
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Intensity level
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Loudness
Questão 36
Questão
If the period of a wave is 0.02 s, what is its frequency? (Hint: how often does it vibrate in one second?)
Questão 37
Questão
A person screams in the mountain and hears the echo after 2 seconds. How far was the cliff that caused the reflection of the sound (echo)?
Questão 38
Questão
Which of the following properties of sound is measured in Hertz (Hz)?
Responda
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Power
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Amplitude
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Frequency
Questão 39
Questão
When sound wave propagates between two media with similar impedance, there will be:
Responda
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Equal amounts of transmission and reflection
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Be more transmission and less reflection
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Be more reflection and less transmission
Questão 40
Questão
The human ear is sensitive to frequencies in the range:
Responda
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20 Hz – 20 MHz
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200 Hz – 20 kHz
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20 Hz – 2000 Hz
Questão 41
Questão
What are the SI units for loudness?
Questão 42
Questão
The speed of sound in the human body is approximately:
Responda
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330 m/s
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1500 m/s
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6000 m/s
Questão 43
Questão
The audiogram is a method for hearing loss evaluation by measuring the threshold hearing intensity of sound for different:
Responda
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Frequencies
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Wavelengths
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Amplitudes
Questão 44
Questão
Pure tone is characterized by:
Questão 45
Questão
When sound wave travels from air into the human body, what happens to its speed?
Responda
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Increases, because tissue has higher acoustic impedance
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Decreases, because tissue has lower acoustic impedance
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It doesn’t change because the speed of sound is constant