PADI Diving Theory & Safety 2 — Questions and Answers
Question 1: A diver ascends too quickly from 30 meters. Which condition is MOST likely to result?
- Nitrogen narcosis
- Decompression sickness (Correct answer)
- Oxygen toxicity
- Carbon dioxide buildup
Correct answer: Decompression sickness
Rapid ascent allows dissolved nitrogen to form bubbles in tissues and blood, causing decompression sickness.
Question 2: What is the purpose of the 'safety stop' recommended by PADI at 5 meters for 3 minutes?
- To allow equalization of the ears
- To reduce the risk of decompression sickness (Correct answer)
- To conserve remaining air supply
- To signal surface support of your ascent
Correct answer: To reduce the risk of decompression sickness
A safety stop at 5 meters for 3 minutes allows excess nitrogen to off-gas safely before surfacing.
Question 3: Boyle's Law states that at a constant temperature, the volume of a gas is:
- Directly proportional to absolute temperature
- Inversely proportional to absolute pressure (Correct answer)
- Directly proportional to absolute pressure
- Independent of pressure changes
Correct answer: Inversely proportional to absolute pressure
Boyle's Law: as pressure increases, volume decreases proportionally (P₁V₁ = P₂V₂ at constant temperature).
Question 4: Which gas law explains why a diver's lungs could rupture if they hold their breath during ascent?
- Henry's Law
- Dalton's Law
- Boyle's Law (Correct answer)
- Charles's Law
Correct answer: Boyle's Law
Boyle's Law explains that trapped gas expands as pressure decreases during ascent, potentially rupturing the lungs.
Question 5: What does a dive computer's 'no-decompression limit' (NDL) indicate?
- The maximum depth you can safely reach
- The maximum time at depth before mandatory decompression stops are required (Correct answer)
- The time remaining before your tank runs out of air
- The minimum surface interval before your next dive
Correct answer: The maximum time at depth before mandatory decompression stops are required
The NDL is the maximum time a diver can spend at a given depth without requiring decompression stops on ascent.
Question 6: A diver experiences pain in their joints and muscles after a dive. This symptom is associated with which condition?
- Arterial gas embolism
- Nitrogen narcosis
- Decompression sickness (Type II) (Correct answer)
- Oxygen toxicity
Correct answer: Decompression sickness (Type II)
Joint and muscle pain ('the bends') are classic Type II DCS symptoms caused by nitrogen bubble formation in tissues.
Question 7: According to PADI standards, what is the maximum recommended ascent rate?
- 9 meters per minute (Correct answer)
- 18 meters per minute
- 30 meters per minute
- 6 meters per minute
Correct answer: 9 meters per minute
PADI recommends ascending no faster than 9 meters (30 feet) per minute to allow safe nitrogen off-gassing.
PADI Diving Theory & Safety 2
A diver ascends too quickly from 30 meters.
Which condition is MOST likely to result?