Undersea Warfare

Question 1

A sonar transducer can be compared to what?

Answer 1

Speaker

Question 2

Signal strength lost as sound waves travel through water is known as what?

Answer 2

Transmission loss

Question 3

What sea state causes the greatest amount if absorption

Answer 3

Whitecap waves

Question 4

Sound waves in seawater travel how many times faster than sound waves in the air?

Answer 4

4 times

Question 5

What sea floor surfaces have the least amount of signal loss?

Answer 5

Smooth and hard

Question 6

Multiple reflections of a sound wave is referred to by what term?

Answer 6

Reverberating

Question 7

Meaning of divergence on sound waves

Answer 7

Wave spreads out and becomes weaker with distance

Question 8

What is the most important factor affecting the speed of a sound wave in seawater?

Answer 8

Temperature

Question 9

An increase in the salinity of seawater has what effect on the sound wave?

Answer 9

Speed increases

Question 10

What is the minimum number of sonobuoys normally deployed during a USW mission?

Answer 10

3

Question 11

Sonobuoys that transmit an acoustic pulse and detect a resulting echo are classified a what type of sonobuoy?

Answer 11

Active

Question 12

What are the three methods of deploying a sonobuoy?

Answer 12

Pneumatic, free-fall, and cartridge

Question 13

How are sonobuoys activated?

Answer 13

Saltwater battery activation

Question 14

What happens to the sonobuoy after the battery dies?

Answer 14

It sinks to the bottom

Question 15

The acronym SONAR is derived from what words?

Answer 15

Sound navigation and ranging

Question 16

When the source of a sound wave is moving away from the receiver, what apparent change in the sound wave takes place? (Doppler effect)

Answer 16

The frequency decreases

Question 17

What are the 3 most common propagation paths for sound waves

Answer 17

Direct
Bottom bounce
Convergence

Question 18

Sonobuoy descent-retarding devices are necessary for what reason

Answer 18

Reduce water entry shock

Question 19

A LOLFAR sonobuoy uses what type of hydrophone

Answer 19

Omnidirectional

Question 20

angles of change in the Earths natural magnetic fielf in the east-west direction is known by what term?

Answer 20

Variation angle

Question 21

Max range at which a submarince may be detected depends on the intensity of its magnetic anomaly what what other factor?

Answer 21

The sensitivity of the detector

Question 22

maneuver noises caused to eddy current flow can be minimized by taking what action?

Answer 22

making slow aircraft maneuvers

Question 23

any magnetic field may be defined in terms of what number of axial coordinates?

Answer 23

3

roll, pitch, yaw

Question 24

what is the purposed of the submarine anomaly detector (SAD) system?

Answer 24

separates submarine anomalies from magnetic noise.