Diving Theory & Safety Flashcards

Henry's Law is most relevant to diving because it explains:

Answer: How gases dissolve into liquids under pressure

Henry's Law states that the amount of gas dissolved in a liquid is proportional to the partial pressure of that gas, explaining nitrogen absorption during diving.

Dalton's Law of Partial Pressures states that the total pressure of a gas mixture equals:

Answer: The sum of the partial pressures of each individual gas

Dalton's Law states total gas pressure equals the sum of each individual gas's partial pressure in the mixture.

A diver experiences vision disturbances and convulsions underwater. This is most likely caused by:

Answer: Oxygen toxicity (CNS toxicity)

CNS oxygen toxicity causes visual disturbances, twitching, and convulsions when the partial pressure of oxygen exceeds safe limits.

What is the maximum operating depth (MOD) for EAN32 (Nitrox with 32% oxygen) based on a ppO₂ limit of 1.4 ATA?

Answer: 33.75 meters

MOD = [(ppO₂ limit / FO₂) - 1] × 10m = [(1.4/0.32) - 1] × 10 = 33.75 meters.

Which condition describes the 'rapture of the deep' experienced by divers breathing compressed air at depth?

Answer: Nitrogen narcosis

Nitrogen narcosis ('rapture of the deep') causes impaired judgment and euphoria similar to alcohol intoxication, typically below 30 meters on air.

What fraction of the water surface is illuminated by light absorbed at approximately 10 meters depth?

Answer: Red wavelengths are completely absorbed

Red wavelengths are absorbed first and are almost completely gone by 5-10 meters, which is why blood appears green underwater.

During a dive, a buddy notices the diver's SPG reads 50 bar. According to the rule of thirds, what action should be taken?

Answer: Signal to the buddy and begin a normal ascent

50 bar is typically the reserve level (rule of thirds: 1/3 in, 1/3 out, 1/3 emergency reserve); signal buddy and ascend.