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94 Cards in this Set
- Front
- Back
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Speed of sound in Air?
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1100 fps
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Speed of sound in water?
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4,800 fps
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Speed of sound through steel?
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16,000 fps
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Define Snell's Law (HALT rule)
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Higher Away - Lower towards
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What is the reduction of sound due to Scattering and Reflection?
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Attenuation
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What are the frequencies below 20 Hz, and above 20,000 Hz called?
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Insfrasonic and Ultrasonic
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What has the most effect of sound velocity down to 1,000 ft?
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Temperature
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What has the most eeffect on sound velocity pass 1,000?
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Pressure
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What is absorption?
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Conversion of sound energy to heat
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What is the range of noise produced by rain and hail squalls?
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500-15,000 Hz (ocassionally as low as 100 Hz)
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An isothermal condition will cause sound rays to do what?
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Bend Upwards
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How many degrees in a time zone?
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15 degrees
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What is the formula for converting frequency to temperature?
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(Freq-800)/20=deg F
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What are the three types of Spreading associated with dB loss?
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Cylindrical - 3dB, Spherical - 6dB, Dipolar - 12dB
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How much depth excess is required for usable CZ?
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200 fathoms, 22 fps, 50%
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How much depth excess if requried for reliable CZ?
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300 fathoms, 33 fps, 80%
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What is the East-West deviation of the earth's magnetic field called?
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Magnetic variation
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What is the average CZ range?
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18-36NM / Med 18-22 NM
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What determines sonic layer depth?
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Sound velocity
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An increase in frequency will cause an increase in what?
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Absorption
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Attenuation caused by suspended particles in water is?
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Scattering
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The least seasonal temperature changes occur in what region?
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Equatorial
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What is a high-pressure area in a sound wave known as?
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Compression
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What is a low-pressure area in a sound wave known as?
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rare fraction
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What is the definition of a freqency?
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The number of wavelengths that occur in one second
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Wat is the density of saltwater?
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64 lbs per cubic ft.
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What is the function of a hydrophone?
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Receive sound
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What is the emission of light by living-organisms called?
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Bioluminescence
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At what depth, have subs outlined with bioluminescence been detected?
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250 ft
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Where does the greatest seasonal sea surface temperature change occur?
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Mid Latitudes
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What transmission occurs when sound rays in deep water are refracted then surface reflected?
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CZ
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What is the measurement of absorption of solar energy per unit area?
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Intensity
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What is the bending of sound rays due to variable consistencies?
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Refraction
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What condition is created when a -0.2 degree gradient occurs?
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Isothermal
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What is the loss of sound intesity due to Asorption and Scattering?
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Attenuation
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What will cause a reduction in salinity in the polar region?
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Ice melt
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All sound spreading starts as what kind?
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Spherical
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What initally affects a sonar ping?
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Absorption
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What type of noise does the sun produce?
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temporal
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What is the primary facor effecting IRDS?
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Moisture
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What is the maximum sea state for a submarine to transfer?
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Sea state 5
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The ocean bottom consists of what four main parts?
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Continental Slope, continental Shelf, ridges and abyssal plains
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If you increase acoustic intensity by 1000 times, how many dB have you gained?
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30 dB
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What is the November index?
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HF propagation -- 1 - useless / 9 - excellent
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What is the Kilo index?
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Temporal or Geomagnetic noise (variations in the earth's magnetic fields)
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When is the Deep Scattering Layer the shallowest?
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Night time
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What is RF energy most effected by?
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Tempterature
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What has the most effect on spreading?
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distance
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What does CAVU mean?
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Ceiling and Visibility Unlimited
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What is a VATB?
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Short form weather report (Visibility, Amount, Tops of Clouds, Bottoms of Clouds)
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What is a BOWWAVE
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Long form weather report (Base, Tops, Wind, Weather, Amount, Visibility, Extra)
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What is shallow water?
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100 fathoms or less
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In the Equatorial region, what is the most predominate time for the afternoon effect?
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1400-1500L (2pm to 3pm)
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Where is the riches area for bioluminescence to occur?
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Arabian Sea
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What is the color of bioluminescence?
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Green or Blue
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How many Gammas are at the Poles and at the Equator?
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65,000 and 25,000 Gammas
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How long is a MAD index good for?
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3 days
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100 ft in altitude equals how many Gammas?
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1 Gamma
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What is the speed of light?
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162,000 NM/Sec
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What is a radar range mile?
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81,000 NM/Sec
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How many Gammas equal an Orsted?
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100,000 Gammas
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What is the smallest form of luminescent?
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Bacteria
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Convert 72 degrees F to Celcius.
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22.2 deg C
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How long is the Alfa index good for?
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72 Hours
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What is the range for the Alfa index?
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0-25 Disturbed
25-50 Severely Degraded 50-400 Unusable |
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What is absolute zero in Celcius?
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-273 Degrees Celcius
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How much will a 100 ft dept change in the sound velocity?
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-1.7 fps
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How much will a 1 degree in temperature change sound velocity?
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4-8 fps
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How much will a 1/1000 ppt in salinity change sound velocity?
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3-5 fps
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Define TSP.
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4800 fps -
39 degrees F 35 ppt 0 ft |
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What ware condition will cause the least absorption?
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Smooth Sea Surface
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What will scatter less sound? Pebbles or Sand
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Sand
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How much do Gammas change in North-South travel?
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-8 Gammas per Degree
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What are the three types of reverberation (scattering)?
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Surface, Volume, and Bottom
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All sound starts as what transmission path?
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Direct Path
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How far can river runoff extend?
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200 miles (uper 30-50ft)
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33 ft in depth equals what?
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1 Atmosphere
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What percent of the sun's engery is absorbed within how many inches?
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66%, 2 inches
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What type of spreading will have the lowest loss and the greatest detection range?
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Cylindrical
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What percentage of sound radiated by submarines goes into bottom bounce?
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87%
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What bottom type will give the worst reflection?
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Clay (20%)
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What will give the best bottom reflection?
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Pebbles (70%)
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Whales are capable of making sound to what frequency?
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50Hz
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What are the two types of sound waves?
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Transverse and Longitudinal
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What are the dip angles at the poles and the equator?
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90, 0
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What is Sub-refraction?
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A cure away from the earth.
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What is Diffraction?
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A bend around an object.
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What is super-refraction?
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A curve towards the earth.
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What is IRDS measured in?
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microns
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What type of water can give CZ?
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Deep Sound channel sound speed is at or greater than near surface velocity. (22fps - 50%, 33fps - 80%)
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What is turbidity?
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Water with large quantities of clay, silt and sand in suspsention.
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Mad setting at 2.5, .8 gamma signal, what percentage of paper is signal?
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32% (divide Mad setting by gamma signal)
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Wind being blown upwards away and replaced by air off the cool water is called?
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Upwelling
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What raypath has the longest detection ranges?
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CZ or Half Channel
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