Divemaster Final Exam A & B Package Deal
2025/2026
150-Question Complete Practice Exam with
Questions and Answers
Section I: Dive Physics (1–20)
1. At sea level, what is the absolute pressure?
A. 0 bar
B. 1 bar
C. 2 bar
D. 3 bar
Correct Answer: B
Rationale: At sea level, atmospheric pressure is 1 bar (or 1 atmosphere).
2. What is the absolute pressure at 20 meters of seawater?
A. 1 bar
B. 2 bar
C. 3 bar
D. 4 bar
Correct Answer: C
Rationale: Every 10 meters of seawater adds 1 bar. At 20 m: 1 bar atmospheric + 2 bar
water = 3 bar absolute.
3. According to Boyle's law, if pressure doubles, gas volume:
A. Doubles
B. Halves
C. Stays the same
D. Triples
, Correct Answer: B
Rationale: Boyle's law: volume is inversely proportional to pressure. Doubling pressure
halves volume.
4. A balloon has 6 liters of air at the surface. What is its volume at 10 meters?
A. 2 liters
B. 3 liters
C. 6 liters
D. 12 liters
Correct Answer: B
Rationale: At 10 m, pressure is 2 bar. Volume = 6 L × (1 bar / 2 bar) = 3 liters.
5. Which gas law explains why a diver must exhale continuously during a emergency ascent?
A. Charles's law
B. Boyle's law
C. Dalton's law
D. Henry's law
Correct Answer: B
Rationale: Boyle's law: expanding air during ascent must be exhaled to prevent lung
overexpansion injury.
6. What is the density of water compared to air?
A. About 100 times
B. About 400 times
C. About 800 times
D. About 1000 times
Correct Answer: C
Rationale: Water is approximately 800 times denser than air.
7. How does sound travel in water compared to air?
A. Slower
B. Faster
,C. Same speed
D. Cannot travel
Correct Answer: B
Rationale: Sound travels about four times faster in water than in air.
8. Which color is absorbed first underwater?
A. Blue
B. Green
C. Red
D. Yellow
Correct Answer: C
Rationale: Red light is absorbed first as depth increases.
9. What is the partial pressure of oxygen in air at 40 meters using air (21% O₂)?
A. 0.21 bar
B. 0.84 bar
C. 1.05 bar
D. 1.26 bar
Correct Answer: C
Rationale: At 40 m, absolute pressure is 5 bar. PO₂ = 0.21 × 5 = 1.05 bar.
10. What is the recommended maximum PO₂ for working dives?
A. 0.5 bar
B. 1.0 bar
C. 1.4 bar
D. 2.0 bar
Correct Answer: C
Rationale: The recommended maximum PO₂ for working dives is 1.4 bar.
11. What is the maximum PO₂ for decompression or contingency?
A. 1.2 bar
B. 1.4 bar
, C. 1.6 bar
D. 2.0 bar
Correct Answer: C
Rationale: The maximum PO₂ for decompression or contingency is 1.6 bar.
12. What is the absolute pressure at 30 meters of seawater?
A. 2 bar
B. 3 bar
C. 4 bar
D. 5 bar
Correct Answer: C
Rationale: At 30 m: 1 bar atmospheric + 3 bar water = 4 bar absolute.
13. A gas is at 4 bar absolute and has a volume of 3 liters. What is its volume at 2 bar absolute?
A. 1.5 liters
B. 3 liters
C. 6 liters
D. 12 liters
Correct Answer: C
Rationale: P₁V₁ = P₂V₂: 4 × 3 = 2 × V₂, so V₂ = 6 liters.
14. Which law states that the total pressure of a gas mixture is the sum of partial pressures?
A. Boyle's law
B. Charles's law
C. Dalton's law
D. Henry's law
Correct Answer: C
Rationale: Dalton's law states total pressure is the sum of partial pressures.
15. Which law explains why nitrogen dissolves in tissues under pressure?
A. Boyle's law
B. Charles's law
2025/2026
150-Question Complete Practice Exam with
Questions and Answers
Section I: Dive Physics (1–20)
1. At sea level, what is the absolute pressure?
A. 0 bar
B. 1 bar
C. 2 bar
D. 3 bar
Correct Answer: B
Rationale: At sea level, atmospheric pressure is 1 bar (or 1 atmosphere).
2. What is the absolute pressure at 20 meters of seawater?
A. 1 bar
B. 2 bar
C. 3 bar
D. 4 bar
Correct Answer: C
Rationale: Every 10 meters of seawater adds 1 bar. At 20 m: 1 bar atmospheric + 2 bar
water = 3 bar absolute.
3. According to Boyle's law, if pressure doubles, gas volume:
A. Doubles
B. Halves
C. Stays the same
D. Triples
, Correct Answer: B
Rationale: Boyle's law: volume is inversely proportional to pressure. Doubling pressure
halves volume.
4. A balloon has 6 liters of air at the surface. What is its volume at 10 meters?
A. 2 liters
B. 3 liters
C. 6 liters
D. 12 liters
Correct Answer: B
Rationale: At 10 m, pressure is 2 bar. Volume = 6 L × (1 bar / 2 bar) = 3 liters.
5. Which gas law explains why a diver must exhale continuously during a emergency ascent?
A. Charles's law
B. Boyle's law
C. Dalton's law
D. Henry's law
Correct Answer: B
Rationale: Boyle's law: expanding air during ascent must be exhaled to prevent lung
overexpansion injury.
6. What is the density of water compared to air?
A. About 100 times
B. About 400 times
C. About 800 times
D. About 1000 times
Correct Answer: C
Rationale: Water is approximately 800 times denser than air.
7. How does sound travel in water compared to air?
A. Slower
B. Faster
,C. Same speed
D. Cannot travel
Correct Answer: B
Rationale: Sound travels about four times faster in water than in air.
8. Which color is absorbed first underwater?
A. Blue
B. Green
C. Red
D. Yellow
Correct Answer: C
Rationale: Red light is absorbed first as depth increases.
9. What is the partial pressure of oxygen in air at 40 meters using air (21% O₂)?
A. 0.21 bar
B. 0.84 bar
C. 1.05 bar
D. 1.26 bar
Correct Answer: C
Rationale: At 40 m, absolute pressure is 5 bar. PO₂ = 0.21 × 5 = 1.05 bar.
10. What is the recommended maximum PO₂ for working dives?
A. 0.5 bar
B. 1.0 bar
C. 1.4 bar
D. 2.0 bar
Correct Answer: C
Rationale: The recommended maximum PO₂ for working dives is 1.4 bar.
11. What is the maximum PO₂ for decompression or contingency?
A. 1.2 bar
B. 1.4 bar
, C. 1.6 bar
D. 2.0 bar
Correct Answer: C
Rationale: The maximum PO₂ for decompression or contingency is 1.6 bar.
12. What is the absolute pressure at 30 meters of seawater?
A. 2 bar
B. 3 bar
C. 4 bar
D. 5 bar
Correct Answer: C
Rationale: At 30 m: 1 bar atmospheric + 3 bar water = 4 bar absolute.
13. A gas is at 4 bar absolute and has a volume of 3 liters. What is its volume at 2 bar absolute?
A. 1.5 liters
B. 3 liters
C. 6 liters
D. 12 liters
Correct Answer: C
Rationale: P₁V₁ = P₂V₂: 4 × 3 = 2 × V₂, so V₂ = 6 liters.
14. Which law states that the total pressure of a gas mixture is the sum of partial pressures?
A. Boyle's law
B. Charles's law
C. Dalton's law
D. Henry's law
Correct Answer: C
Rationale: Dalton's law states total pressure is the sum of partial pressures.
15. Which law explains why nitrogen dissolves in tissues under pressure?
A. Boyle's law
B. Charles's law
