NS2-M3C23 - Sound and Sonar (Exam)

In order for the human ear to hear a sound what is the minimum intensity the sound must

be?

• 120 watts/square meters

• 0.001 watts/ square meters

• 10^-12 watts/ square meters

In what form do sound vibrations enter the surrounding source?

• pressure waves

• surface waves

• longitudinal waves

Choose the answer that corrects the sentence.

In a medium with variable density and temperature, waves spread in expanding three-dimensional spheres, losing energy as each sphere expands.

• Change “expands” to “contracts”

• Change “losing” to “gaining”

• Change “variable” to “uniform”

• Change “expanding” to “contracting”

A membrane of the middle ear that vibrates in response to sound waves; the tympanic membrane

• Inner ear

• Ear Canal

• Eardrum

The essential organ of hearing and equilibrium that is located in the temporal bone, in innervated by the auditory nerve and includes the vestibular, the semicircular canals and the cochlea

• Ear Canal

• Eardrum

• Inner ear

• Sound intensity

The speed of sound waves in water is affected by which of the following? (Input all that

apply, then push the ENTER button.)

• None of the above

• Temperature

• Salt content

• Surface area

• Pressure

When an object such as an airplane approaches you the frequency waves that reach your ear are closer together, resulting in a higher frequency. As the sound source, in this case the airplane, moves away the frequency waves are __________.

• closest together

• the same distance as the waves when the airplane was approaching

• further apart

• the same distance as the waves at the source

What is the difference between active and passive sonar?

• Active sonar monitors for movement; passive sonar listens for sounds.

• Active sonar sends out sound waves; passive sonar receives them.

• Submarines typically use active sonar; ships typically use passive.

The change between the highest and lowest frequencies heard and the source frequency. It can be used to determine the speed and direction of motion of a sound’s source, such as a submarine in the ocean

• Doppler transition

• Doppler shift

• Doppler effect

• Doppler movement

A device equipped for detecting underwater sounds and transmitting them by radio

• Hydrophone

• Sonobuoy

• Passive sonar