Nautical Sciences, Unit Five, Chapter Five: Sound and Sonar
This is an Closed Book, Multiple-choice exercise.
Use your mouse to click the box next to the most correct answer. If you fail to select the correct answer you must try again until you select the correct answer.
The amount of energy or power in a sound wave at any given location is called what?
Sound intensity
Sound frequency
Sound medium
Doppler effect
Sound voltage
True or False: Because sound waves are material waves, the more material there is per unit volume in the medium, the better sound will travel through it.
True
False
How does temperature of a medium affect sound waves traveling through it?
The warmer the material, the faster sound waves move through it.
The cooler the material, the slower the sound waves move through it.
Temperature does not affect the movement of sound waves through mediums.
The warmer the material, the slower the sound waves move through it.
Very cold and very hot mediums transmit sound waves the best.
The bending of a sound wave as it strikes a material is called what?
Refraction
Diffraction
Reflection
Absorption
Ducting
If the speed of sound in air is 350 meters per second, and when you yell you hear your echo 4 seconds later, how far away is the object off of which your voice bounced?
700 meters
350 meters
1,400 meters
4 meters
There isn't enough information give to determine the distance.
What do negative sound decibel levels indicate?
Sounds too faint to be heard without amplification.
There is no such thing as negative sound decibel levels.
Sounds that are near the bottom range of human hearing.
Negative sound decibels levels indicate the level a human ear can stand without pain as the eardrum begins to tear.
They indicate ultrasound ranges.
The apparent change in frequency or pitch of a sound as it approaches and then passes you is known as what?
Doppler shift
Coriolis effect
Decibel shift
Ultrasound effect
Cochlea effect
Where would you find the hammer, anvil and stirrup in the human ear.
In the middle ear
In the outer ear
In the inner ear
In the cochlea
Inside the brain
Which of the following would NOT be an example of the use of the principal of Doppler Shift?
Measuring the distance to a sonar contact.
Measuring the speed of a baseball.
Measuring the speed of a moving car.
Determining the direction of motion of a submarine in the ocean.
Determining whether a star is moving towards or away from the Earth.
Which of the following is NOT a factor affecting the speed of sound underwater?
Frequency
Temperature
Pressure
Salinity
All of these are factors that affect the speed of sound underwater
Which is the most important factor affecting the speed at which sound waves move through water?
Temperature
Salinity
Pressure
Frequency
Decibel level
What is the overall order of the following items, from the one that has the greatest impact on the speed of sound through water to the one that has the least affect?
Temperature, salinity, pressure
Temperature, pressure, salinity
Salinity, pressure, temperature
Salinity, temperature, pressure
Pressure, temperature, salinity
What was the earliest SONAR device?
The hydrophone
The fathometer
The sonobuoy
The Doppler
The echo sounder
What type of SONAR transmits underwater sound pulses that strike targets and return as echos?
Active
Passive
Doppler
Hydrophones
RADAR
What type of U.S. Navy platform uses active SONAR the most?
Undersea warfare ships
Helicopters
Aircraft
Submarines
Aircraft Carriers
What type of SONARs do not emit sound?
Passive SONARS
Active SONARS
Sonobuoys
Dipping SONAR
Silent SONARS
What is the name of the instrument used to determine the depth of the water under the hull?
A fathometer
A dipping SONAR
A passive SONAR
A hydrophone
A towed array
Small expendable floating hydrophone units dropped by antisubmarine aircraft are called what?