Chapter 7 - Acoustic Fundamentals

Question 1

Sound is defined as:

A. Audible vibrations of air.
B. Audible or inaudible vibrations of matter.
C. Audible vibrations of particles of matter in air.
D. Audible vibrations of particles in matter.

Answer 1

D. Audible vibrations of particles in matter.

Question 2

In transverse waves, the displacement of particles is _____ to the direction of the propagation of the wave.

A. Parallel to the direction of the wave.
B. Perpindicular to the direction of the wave.
C. Neither.

Answer 2

B. Perpindicular to the direction of the wave.

Question 3

In longitudinal waves, the displacement of particles is _____ to the direction of the propagation of the wave.

A. Perpindicular to the direction of the propagation of the wave.
B. Parallel to the direction of the propagation of the wave.
C. Neither.

Answer 3

B. Parallel to the direction of the propagation of the wave.

Question 4

Sound waves are _____ waves.

A. Longitudinal.
B. Transverse.
C. Water.
D. Other.

Answer 4

A. Longitudinal.

Question 5

Sound is also a _____ wave.

A. Disbursing.
B. Angular.
C. Volume.
D. Pressure.

Answer 5

D. Pressure.

Question 6

For sound to occur, a force must act against _____.

A. Air, water, or solids.
B. Oscillations.
C. Pressure forces.
D. Particles.

Answer 6

D. Particles.

Question 7

Therefore, sound cannot travel or propagate in a _____.

A. Dense atmosphere.
B. Material like wood or plastic.
C. In salt water.
D. Vacuum.

Answer 7

D. Vacuum.

Question 8

A sound wave is also defined as a _____ wave.

A. Cosine.
B. Tangent.
C. Secant.
D. Sine.

Answer 8

D. Sine.

Question 9

The three media through which sound can travel are: (check all that apply)

A. Air.
B. Wood.
C. Methane.
D. Gas.
E. Liquid.
F. Solid.

Answer 9

D. Gas.
E. Liquid.
F. Solid.

Question 10

The highest points on this traveling wave are points of _____. (check all that apply)

A. Rarefaction.
B. Compression.
C. Peak Amplitude.

Answer 10

B. Compression.
C. Peak Amplitude.

Question 11

Sound travels through air at the rate of _____ meters per second (_____ miles per hour).

A. 150/347.
B. 347/770.
C. 1,500/9,000
D. 5,960/13,330.

Answer 11

B. 347/770.

Question 12

Sound travels through water at the rate of _____ meters per second (_____ miles per hour).

A. 347/770.
B. 1,500/3,060.
C. 5,960/13,330

Answer 12

B. 1,500/3,060.

Question 13

Sound travels through steel at the rate of _____ meters per second (_____ miles per hour).

A. 347/770.
B. 1,500/3,060.
C. 5,960/13,330.

Answer 13

C. 5,960/13,330.

Question 14

Does the fact that sound travels at approximately 770 miles per hour mean that each sound will travel that far?

A. Yes.
B. No.
C. Not sure.

Answer 14

B. No.

Question 15

The distance a sound travels, regardless of the medium it travels through, depends upon its original _____ along with the medium it travels through.

A. Loudness.
B. Force.
C. Intensity.
D. Source.

Answer 15

C. Intensity.

Question 16

Since the velocity of sound is approximately the same for all wavelengths, frequency is often used to better describe the effects of the different wavelengths. The equation for the relationship between wavelength and frequency is:

A. velocity = wavelength/ frequency
B. velocity = wavelength x frequency + amplitude
C. velocity = wavelength x frequency

Answer 16

C. velocity = wavelength x frequency

Question 17

The human hearing spectrum is limited, just as the human vision spectrum. The lowest an average person can hear is _____ cycles per second (Hertz).

A. 20.
B. 120.
C. 140.
D. 14.
E. None of the above.

Answer 17

A. 20.

Question 18

The human hearing spectrum is limited, just as the human vision spectrum. The highest an average person can hear is _____ cycles per second (Hertz).

A. 2,000.
B. 12,000.
C. 20,000.
D. 32,000.
E. 132,000.

Answer 18

C. 20,000.

Question 19

Wavelength is defined as:

A. The length between the beginning and end of a wave.
B. The distance between two waves, one twice as deep as the other.
C. The distance between maximum points of compression.
D. How far a wave travels.

Answer 19

C. The distance between maximum points of compression.

Question 20

Frequency is defined as:

A. The total number of wavelengths in a pure tone sound.
B. The velocity of a sound divided by the mass of the medium.
C. The rate at which a sound wave passes a given point.

Answer 20

C. The rate at which a sound wave passes a given point.

Question 21

The amplitude of a sound describes how much energy the sound has.

A. True.
B. False.

Answer 21

A. True.

Question 22

Ampltiude and frequency are not independent of each other.

A. True.
B. False.

Answer 22

B. False.

Question 23

When you softly strike the Middle C key on the piano, you create a sound with a frequency of 256 Hz. When you strike the same key as hard as you can, you have changed the _____.

A. Amplitude and frequency.
B. Only the frequency.
C. Only the amplitude.
D. Cost of your piano lessons.

Answer 23

C. Only the amplitude.

Question 24

All letters in the alphabet can be spoken in words with the same amplitude. It’s best to try voicing them all to make sure you get the right answer to this question.

A. True.
B. False.
C. Hey, we didn’t have this in the video lesson.

Answer 24

A. True.

Question 25

You will see the term ‘compression amplitude’ in the hearing care field because: A. The amplitude of a sound wave compresses the stimulus it evokes. B. The amplitude of a sound wave is the amount of compression the stimulus creates. Sound is a compression wave.

Answer 25

B. The amplitude of a sound wave is the amount of compression the stimulus creates. Sound is a compression wave.

Question 26

The normal hearing organ can detect the sound which moves particles in the air a distance of _____ of a centimeter. A. One thousandth. B. Ten thousandths. C. One millionth. D. One one hundred millionth. E. One billionth.

Answer 26

E. One billionth.

Question 27

This sound has an intensity of 1 times 10 to the minus 16th Watts per centimeter squared. A. True. B. False.

Answer 27

A. True.

Question 28

This is a mathematical calculation that forms the basis for: A. Loudness. B. Amplitude. C. Compression. D. The threshold of hearing.

Answer 28

D. The threshold of hearing.

Question 29

The threshold of hearing is established as _____ decibels. A. None. B. 0. C. 20. D. 256. E. 2,560.

Answer 29

B. 0.

Question 30

The term loudness means the same to everyone with normal hearing. A. True. B. False.

Answer 30

B. False.

Question 31

A guitar note may be high pitched to me and _____ pitched to you. Who is right? A. Medium/you are. B. Medium/I am. C. Any description/I am. D. Any description/We both are.

Answer 31

D. Any description/We both are.

Question 32

As a hearing instrument specialist, you will be giving tests that have subjective and objective components. Objective components are _____ and _____. A. Measurable and open to discussion. B. Measurable and open to change. C. Measureable and not open to personal judgment. D. Subjective and not open to discussion.

Answer 32

C. Measureable and not open to personal judgment.

Question 33

Frequency is: A. A subjective measurement. B. An objective measurement. C. Measurable, thus objective. D. Measurable but subjective.

Answer 33

C. Measurable, thus objective.

Question 34

If I strike the Soprano C on the piano, it is measured at about 1024 Hertz and at an amplitude depending on how hard I strike it. Right? Yes. So, you can call it a low, soft, medium loud, fat key, but it’s still _____. A. A nice sound. B. A high note. C. Pretty. D. 1,024 Hertz which will be the same every time it's played no matter how you feel about it or describe it.

Answer 34

D. 1,024 Hertz which will be the same every time it's played no matter how you feel about it or describe it.

Question 35

So, frequency is objective and pitch, subjective. A. True. B. False. C. Whew.

Answer 35

A. True.

Question 35

Yet, as you are asked to describe the pitch, you are asked to describe it according to how you perceive it. That makes it _____. A. Objective. B. Subjective.

Answer 35

B. Subjective.

Question 36

Dynamo, dynamite, dynamic, all refer to the Greek root – Dunamis (Δύναμις). This word means: A. Strong. B. Power. C. Force.

Answer 36

B. Power.

Question 37

The unit of force is the dyne. A. True. B. False.

Answer 37

A. True.

Question 38

Decibels in dynes = decibels [dB] Sound Pressure Level (SPL). A. True. B. False.

Answer 38

A. True.

Question 39

0.0002 dynes per centimeter squared is _____. A. Sound in a vacuum. B. No sound. C. 0 dB. D. 0 dB SPL.

Answer 39

D. 0 dB SPL.

Question 40

50 dB SPL + 50 dB SPL = _____. A. 100 dB. B. 1000 dB. C. 56 dB SPL.

Answer 40

C. 56 dB SPL.

Question 41

For every increase in intensity of 10 dB, the average increase in loudness increases by about _____. A. A factor of one. B. A factor of two. C. A factor of ten. D. None of the above.

Answer 41

B. A factor of two.

Question 42

Perceptions of persons with hearing loss may be due to: A. The fact that their normal level changes over time. B. The impact of noise. C. The impact of aging. D. The impact of a lack of education on the subject. E. All of the above.

Answer 42

E. All of the above.

Question 43

This is why you need to be _____ when dealing with subjective explanations. A. Cautious. B. Careful. C. Conservative. D. All three C's.

Answer 43

D. All three C's.

Question 44

Threshold are _____ specific. A. Pitch. B. Frequency. C. Tone. D. Amplitude.

Answer 44

B. Frequency.

Question 45

The term ‘dB in Hearing Level [dB HL]’ is used in hearing testing because the human ear is ‘frequency specific’ sensitive and will naturall amplify sounds within the speech spectrum [1000 to 5000 Hz]. A. True. B. False.

Answer 45

A. True.

Question 46

The audiometer is calibrated for differential SPL levels. A. True. B. False. C. It isn't enough to make a difference.

Answer 46

A. True.