SHS 311 quiz and pretest Questions and Answers With Verified Solutions 2025
If a sounds Frequency (f) is 3500 Hz, and the Speed of Sound (c) is 350 meters/sec, what is the sound's
Wavelength (λ)? - ✔✔.1 meter (λ=c/f = 350m/sec/3500 Hz) = .1
Sound Pressure changes when which of these variables changes? - ✔✔Velocity of the gas (air molecules)
Pressure is proportional to density and velocity (or acceleration)
What is a decibel (dB)? - ✔✔20log(p/po) = 20 log the ratio of two pressures (p)
If sound pressure increases by a factor of 10,000 how many dB is this? - ✔✔80 dB 20log(10,000)=20*4 (4
zeros) = 80 dB
If one measures sound level at 2 meters from the sound source, then at 4 meters from the sound
source, ideally by what factor will the sound level decrease over from 2 to 4 meters? - ✔✔Decreases by
a factor of 4 Distance doubles, intensity decreases by the square of a double or a factor of 4.
What are the two main parts of impedance? - ✔✔Resistance and Reactance
If the wavelength (λ)of sound is 50 cm, what size object is likely to produce a sound
shadow? - ✔✔About 50 cm
What is the frequency of a standing wave proportional to? - ✔✔Length of string
What are the two graphs used to describe a sound in the Frequency Domain? - ✔✔Phase Spectrum and
Amplitude Spectrum
A researcher makes a small change to the phase difference between two sinusoids used to generate a
complex sound, which is true? - ✔✔Both the time domain and frequency domain descriptions will
change
, Which is likely to happen to the width of amplitude spectrum if the duration of its time domain
waveform was increased? - ✔✔The width of the spectrum would likely decrease
If the roll-off of a filter is 10dB/Octave, what would be the filter's attenuation at a frequency two
octaves away from the filter's cutoff frequency? - ✔✔If the attenuation "rolls off" at 10 dB/Octave,
them one octave away the attenuation is 10 dB, and two octaves away the attenuation is another 10 dB
for a total of 20 dB (10 dB for each Octave).
Which is a low-pass filter? - ✔✔The amplitude of sinusoidal components with frequencies above 2500
Hz are attenuated
What function does the Pinna provide? - ✔✔The Pinna filters the sound so that the spectrum of the
sound depends on the location of the sound source relative to the Pinna
If the middle ear increases the pressure of the incoming sound by a factor of 1000, how many dB would
this be? - ✔✔60 dB
The Eustachian tube helps solve what problem: - ✔✔Keeping equal pressure on each side of the
Tympanic Membrane
What is not a path by which sound can reach the inner ear? - ✔✔Cheek Bone
If the refractory period for generating an action potential was 1 msec, what would
be the highest frequency (rate) at which repeated action potentials could occur? - ✔✔1000 Hz
Which is not one of the inner ear scala? - ✔✔Superior
What is the helicotrema? - ✔✔Opening at the apex of the cochlea
Why are there two types of Hair Cells? - ✔✔Inner Hair cells are the biological transducer, Outer Hair
Cells effect the biomechanics
If a sounds Frequency (f) is 3500 Hz, and the Speed of Sound (c) is 350 meters/sec, what is the sound's
Wavelength (λ)? - ✔✔.1 meter (λ=c/f = 350m/sec/3500 Hz) = .1
Sound Pressure changes when which of these variables changes? - ✔✔Velocity of the gas (air molecules)
Pressure is proportional to density and velocity (or acceleration)
What is a decibel (dB)? - ✔✔20log(p/po) = 20 log the ratio of two pressures (p)
If sound pressure increases by a factor of 10,000 how many dB is this? - ✔✔80 dB 20log(10,000)=20*4 (4
zeros) = 80 dB
If one measures sound level at 2 meters from the sound source, then at 4 meters from the sound
source, ideally by what factor will the sound level decrease over from 2 to 4 meters? - ✔✔Decreases by
a factor of 4 Distance doubles, intensity decreases by the square of a double or a factor of 4.
What are the two main parts of impedance? - ✔✔Resistance and Reactance
If the wavelength (λ)of sound is 50 cm, what size object is likely to produce a sound
shadow? - ✔✔About 50 cm
What is the frequency of a standing wave proportional to? - ✔✔Length of string
What are the two graphs used to describe a sound in the Frequency Domain? - ✔✔Phase Spectrum and
Amplitude Spectrum
A researcher makes a small change to the phase difference between two sinusoids used to generate a
complex sound, which is true? - ✔✔Both the time domain and frequency domain descriptions will
change
, Which is likely to happen to the width of amplitude spectrum if the duration of its time domain
waveform was increased? - ✔✔The width of the spectrum would likely decrease
If the roll-off of a filter is 10dB/Octave, what would be the filter's attenuation at a frequency two
octaves away from the filter's cutoff frequency? - ✔✔If the attenuation "rolls off" at 10 dB/Octave,
them one octave away the attenuation is 10 dB, and two octaves away the attenuation is another 10 dB
for a total of 20 dB (10 dB for each Octave).
Which is a low-pass filter? - ✔✔The amplitude of sinusoidal components with frequencies above 2500
Hz are attenuated
What function does the Pinna provide? - ✔✔The Pinna filters the sound so that the spectrum of the
sound depends on the location of the sound source relative to the Pinna
If the middle ear increases the pressure of the incoming sound by a factor of 1000, how many dB would
this be? - ✔✔60 dB
The Eustachian tube helps solve what problem: - ✔✔Keeping equal pressure on each side of the
Tympanic Membrane
What is not a path by which sound can reach the inner ear? - ✔✔Cheek Bone
If the refractory period for generating an action potential was 1 msec, what would
be the highest frequency (rate) at which repeated action potentials could occur? - ✔✔1000 Hz
Which is not one of the inner ear scala? - ✔✔Superior
What is the helicotrema? - ✔✔Opening at the apex of the cochlea
Why are there two types of Hair Cells? - ✔✔Inner Hair cells are the biological transducer, Outer Hair
Cells effect the biomechanics
