Diving Physics
Questions
Multiple Response, 10 points
1. Select all that apply to "atmospheric pressure". There are at least three correct answers.
[ ]increases with water depth / [ ]the force acting on a unit area[ ]the pressure exerted by a single gas in a mixture / [ ]pressure due to the weight of water
[ ]1 atm / [ ]decreases with altitude
[ ]14.7 psi
Multiple Response, 10 points
2. Select all that apply to "hydrostatic pressure". There are at least four correct answers.
[ ]the pressure exerted by a single gas in a gas mixture / [ ]the sum of atmospheric and absolute pressures[ ]decreases with altitude / [ ]increases with water depth
[ ]pressure due to the weight of water / [ ].432 psi per foor freshwater
[ ]the force acting on a unit area / [ ].445 psi per foot seawater
Multiple Response, 10 points
3. Select all that apply to "absolute pressure. There are at least three correct answers.
[ ]pressure due to the weight of water / [ ]the difference between atmospheric pressure and the pressure being measured[ ]ata / [ ]increases with water depth
[ ]the sum of atmospheric and hydrostatic pressures / [ ]the pressure exerted by a single gas in a gas mixture
Multiple Response, 10 points
4. Select all that apply to "gauge pressure. There are at least three correct answers.
[ ].432 psi per foot seawater / [ ]the difference between atmospheric pressure and the pressure being measured[ ]the sum of atmospheric and hydrostatic pressure / [ ]ata minus 14.7
[ ]the force acting on a unit of area squared / [ ]increases with water depth
[ ]the pressure exerted by a single gas in a gas mixture
Multiple Choice, 10 points
5. As depth increases the ______of the breathing gas increases.
( )specific gravity / ( )volume( )pH / ( )density
True/False, 10 points
6. Specific gravity is the ratio of the weight of a given volume of a substance (density) to that of an equal volume of another substance.
( )True / ( )FalseMultiple Response, 10 points
7. Select all that apply to "freshwater". There are at least three correct answers.
[ ]has a density of 62.4 pounds per cubic foot / [ ]is a good conductor of electricity[ ]contains almost every substance known / [ ]has a density of 64 pounds per cubic foot
[ ]in its purest form, is a poor conductor of electricity / [ ]freezes at 32 degrees F (0C), and boils at 212 degrees F (100C).
Multiple Response, 10 points
8. Select all that apply to "seawater". There are at least three correct answers.
[ ]contains almost every substance known / [ ]is a good conductor of electricity[ ]freezes at 32 degrees F (0 C) / [ ]has a density of 64 pounds per cubic foot
[ ]has a density of 62.4 pounds per cubic foot / [ ]in its purest form, is a poor conductor of electricity
Multiple Choice, 10 points
9. One meter equals 3.28 feet. Convert 25 feet to meters.
( )82 / ( )7.62( )25 / ( )6
Multiple Choice, 10 points
10. One meter equals 3.28 feet. Convert 50 meters to feet.
( )50 / ( )15.24( )164 / ( )150
Matching Drag and Drop, 10 points
11. Match the English and International temperature scale with its absolute temperature counterpart.
Choice / Correct Match / MatchFahrenheit / Rankine
Celsius / Kelvin
Matching Drag and Drop, 10 points
12. Match the choice with its definition.
Choice / Correct Match / MatchHenry's Law / For any gas at a constant temperature, the volume of the gas will vary inversely with the pressure.
Dalton's Law / For any gas at a constant pressure, the volume of the gas will vary directly with the absolute temperature or for any gas at a constant volume; the pressure of the gas will vary directly with the absolute temperature.
Negative Buoyancy / When the weight of the displaced fluid is greater than the submerged object.
Archimedes' Principle / Any object wholly or partly immersed in a fluid is buoyed up by a force equal to the weight of the fluid displaced by the object.
Neutral Buoyancy / When the weight of the object is equal to the weight of the fluid displaced.
Positive Buoyancy / A combination of Charles’ and Boyle’s laws; it is used to predict the behavior of a given quantity of gas when changes may be expected in any or all of the variables (pressure, temperature, volume).
Boyle's Law / The total pressure exerted by a mixture of gases is equal to the sum of the pressures of each of the different gases making up the mixture, with each gas acting as if it alone was present and occupied the total volume.
General Gas Law / The amount of any given gas that will dissolve in a liquid at a given temperature is proportional to the partial pressure of that gas in equilibrium with the liquid and the solubility coefficient of the gas in the particular liquid.
Charles' Law / When the weight of the displaced fluid is less than the weight of the submerged object.
Multiple Response, 10 points
13. Select all that apply to "air". There are at least two correct answers.
[ ]is a natural by-product of metabolism / [ ]has a major role in decompression[ ]is produced by incomplete combustion of fuels and is found in the exhaust of internal-combustion engines and overheated oil-lubricated compressors / [ ]it is composed of approximately 78% Nitrogen, 21% Oxygen, and 1% other gases
[ ]is required for human life / [ ]the most common gas breathed underwater
Matching Drag and Drop, 10 points
14. Match the gas with its characteristic.
Choice / Correct Match / MatchNeon / is required for human life
Nitrogen / causes less voice distortion than helium and has lower thermal conductivity; is expensive and causes increased breathing resistance under work load
Hydrogen / is used extensively in deep diving; it has a lower density that reduces breathing resistance; disadvantages include “Donald Duck” voice and heat loss due to its high thermal conductivity
Carbon Monoxide / is a natural by-product of metabolism; can cause unconsciousness that can be fatal in divers; elevated levels may further predispose a diver to nitrogen narcosis, oxygen toxicity, and decompression sickness
Carbon Dioxide / has narcotic properties and a density that make it inappropriate as a breathing gas; is frequently used to inflate dry suits because its higher density reduces conduction of heat
Helium / has the major role in decompression; as the partial pressure increases with depth, it produces an intoxicated state that is characterized by loss of judgment and disorientation
Oxygen / a poisonous gas which interferes with the blood’s ability to carry oxygen; is produced by the incomplete combustion of fuels and is found in the exhaust of internal-combustion engines and overheated oil-lubricated compressors
Argon / is readily available and produces less breathing resistance at depth than other gases; its major disadvantage is that is explosive
True/False, 10 points
15. Too much moisture in the diver's breathing gas can decrease breathing resistance.
( )True / ( )FalseTrue/False, 10 points
16. Humidity in the form of condensation in the breathing hoses or mask can be a problem in very cold (freezing) conditions.
( )True / ( )FalseMultiple Choice, 10 points
17. Water slows light - causing light to ______as it enters or leaves water. This creates distortion making objects appear larger and, at distances less than 4 feet, closer.
( )refract / ( )diffuse( )be absorbed / ( )magnify
Multiple Choice, 10 points
18. The more dense the medium through which sound travels, the ______.
( )slower its speed / ( )faster its speedMultiple Choice, 10 points
19. _____ is the first wavelength of light to be absorbed by water.
( )Red / ( )Orange( )Green / ( )Blue
Multiple Choice, 10 points
20. One ata of hydrostatic pressure is reached every ___ feet in seawater.
( ).445 / ( )33( )34 / ( ).432