NS2-M3C23 - Sound and Sonar Quiz 62

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

In what form do sound vibrations enter the surrounding source?

• Surface waves

• Longitudinal waves

• Pressure 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 “expanding” to “contracting”

• Change “losing” to “gaining”

• Change “variable” to “uniform”

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

• Eardrum

• Inner ear

• Ear Canal

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

• Inner ear

• Ear Canal

• Eardrum

• 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.)

• Temperature

• Salt content

• Surface area

• Pressure

• None of the above

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 _______.

• further apart

• the same distance as the waves at the source

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

• closest together

The difference between active and passive sonar is that active sonar sends out sound waves while passive sonar receives them.

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

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

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

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