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16 Cards in this Set
- Front
- Back
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Water is able to conduct heat far more efficiently than aire because it is what?
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More dense than air.
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Divers are most affected by what form of heat transmission?
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Conduction
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Water is able to conduct heat about _____ times faster than air.
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20
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The process of light traveling at different speeds as it passes through different substances is called what?
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Refraction
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When viewed underwater , objects normally appear ___ by a ratio of about ___ (actual to the apparent distance)
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closer / 4:3
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When viewed underwater, objects tend to be magnified by a factor of about:
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33%
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Objects appearing to be further away than it's actual distance is called what?
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visual reversal
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The single most important factor effecting visual reversal is what?
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turbidity
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Light waves contain___, while sound waves are comprised of ___.
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electromagnetic energy/mechanical energy
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The density and elasticity of a medium has what effect upon the transmission of sound?
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Then denser and more elastic the medium, the beter sound is transmitted.
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Sound travels approximately ___ times faster than in water than does air.
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four
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Divers have difficulty determing the direction of sound underwater because:
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There is an insufficient delay between the sound striking one ear before another.
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According to Archimedes' Principle, "Any object wholly or partially immmersed in a fluid is buoyed up by a force___.
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equal to the wieght of the fluid displaced by the object..
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The specific gravity of pure water is:
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1.0
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Approximately how much water must be displaced to bring a 900 pound object to the surface if the object displaces 10 cubic feet? The object lies in 132 feet of seawater.
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Slightly more than 4 cubic feet
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An object weighing 750 pounds and displacing 10 cubic feet is lying in 50 feet of fresh water. If the drum is to be used to lift the object to the surface, how much water must be displaced from the drum?
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2 cubic feet
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