1
Divemaster Final Exam A Actual Exam
2026/2027 – Complete Exam-Style Questions
with Detailed Rationales | 100% Verified |
Pass Guaranteed – A+ Graded
[SECTION 1: Diving Physics & Physiology — Questions 1-20]
Q1: A diver takes a flexible container filled with air from the surface (1 ATA) down to a depth of
99 feet (4 ATA). What happens to the volume of air inside the container?
A. The volume remains the same because the container is flexible.
B. The volume doubles.
C. The volume is reduced to one-fourth of the original volume. [CORRECT]
D. The volume increases by 4 times.
Correct Answer: C
Rationale: According to Boyle's Law (P1V1 = P2V2), pressure and volume are inversely
proportional for a flexible container at constant temperature. As pressure increases from 1 ATA to
4 ATA, the volume decreases to one-fourth. This principle explains why wetsuits compress and
buoyancy decreases upon descent. Flexible containers do not maintain volume like rigid
containers.
Q2: Which gas law explains why nitrogen dissolves into the diver's body tissues during a dive?
A. Boyle's Law
B. Henry's Law [CORRECT]
C. Dalton's Law
D. Charles's Law
Correct Answer: B
,2
Rationale: Henry's Law states that the amount of gas dissolved in a liquid is directly proportional
to the partial pressure of that gas above the liquid. As a diver descends, the partial pressure of
nitrogen increases, forcing more nitrogen to dissolve into the tissues (on-gassing). This absorbed
nitrogen is the primary cause of Decompression Sickness (DCS).
Q3: A diver breathing air at depth experiences an alteration in consciousness described as a
"rapturous euphoria" and impaired judgment at 100 feet. This is most likely:
A. Nitrogen Narcosis [CORRECT]
B. Oxygen Toxicity
C. Carbon Monoxide Poisoning
D. Hypothermia
Correct Answer: A
Rationale: Nitrogen Narcosis (also known as "rapture of the deep") is caused by the anesthetic
effect of nitrogen under pressure. It typically becomes noticeable around 100 feet (30 meters)
and worsens with depth. It impairs judgment and coordination, which is why deep dives require
additional training and planning. Oxygen toxicity usually manifests as convulsions.
Q4: A diver holds their breath while ascending from a dive. At 15 feet, they experience sharp
chest pain and shortness of breath. What injury has likely occurred?
A. Decompression Sickness
B. Arterial Gas Embolism (AGE) [CORRECT]
C. Middle Ear Barotrauma
D. Sinus Squeeze
Correct Answer: B
Rationale: Arterial Gas Embolism is the most serious lung overexpansion injury, caused by
expanding air in the lungs rupturing alveoli and entering the bloodstream if breath is held during
ascent. Symptoms usually appear immediately or within minutes and include chest pain,
neurological deficits, or unconsciousness. It is a life-threatening emergency requiring immediate
oxygen and transport to a hyperbaric chamber.
,3
Q5: According to Dalton's Law, if a diver is breathing a gas mixture of 32% Oxygen and 68%
Nitrogen (Nitrox32) at a depth where the ambient pressure is 4 ATA (99 feet), what is the partial
pressure of Oxygen?
A. 0.32 ATA
B. 1.00 ATA
C. 1.28 ATA [CORRECT]
D. 4.00 ATA
Correct Answer: C
Rationale: Dalton's Law states that the total pressure of a gas mixture is equal to the sum of the
partial pressures of each gas in the mixture. To find the partial pressure of Oxygen, multiply the
fraction of Oxygen (0.32) by the ambient pressure (4 ATA). Calculation: 0.32 x 4 = 1.28 ATA.
Q6: Why does a diver require more weight when diving in fresh water compared to salt water?
A. Fresh water is colder than salt water.
B. Salt water is denser than fresh water, providing more displacement. [CORRECT]
C. Fresh water is more buoyant than salt water.
D. The wetsuit compresses more in fresh water.
Correct Answer: B
Rationale: Salt water has a specific gravity of approximately 1.025, meaning it is denser than
fresh water (specific gravity 1.000). Because salt water is denser, it displaces more weight,
making a diver more buoyant. Consequently, a diver needs more lead weight to achieve proper
buoyancy in salt water than in fresh water.
Q7: A diver is planning a dive to 60 feet. Which of the following would represent the maximum
operating depth (MOD) for EANx32 if the maximum partial pressure of Oxygen (PO2) is limited
to 1.4 ATA?
A. 95 feet
, 4
B. 105 feet
C. 111 feet [CORRECT]
D. 130 feet
Correct Answer: C
Rationale: The formula for MOD is ((Maximum PO2 / Fraction of O2) - 1) x 33. For EANx32
(0.32 O2) with a max PO2 of 1.4: (1..32) - 1 = 4.375 - 1 = 3.375. Multiplying 3.375 by 33
feet per atmosphere gives approximately 111 feet. Diving deeper than this risks CNS Oxygen
Toxicity.
Q8: A diver performs a buoyancy check at the surface with an empty BCD and holds a normal
breath. They should float at which level?
A. At eye level (mask barely out of water) [CORRECT]
B. With the top of the head completely out of water
C. At the waist level
D. With fins underwater only
Correct Answer: A
Rationale: A proper buoyancy check indicates the diver is correctly weighted for the end of the
dive (when the tank is low). With a full tank, the diver will be heavy. To be correctly weighted, a
diver with a full BCD inflated and normal breath should float at eye level. If they float too high,
they are overweighted; too low, they are underweighted.
Q9: Which of the following is a symptom of Central Nervous System (CNS) Oxygen Toxicity?
A. Convulsions without warning [CORRECT]
B. Joint pain
C. Itchy skin
D. Nausea
Divemaster Final Exam A Actual Exam
2026/2027 – Complete Exam-Style Questions
with Detailed Rationales | 100% Verified |
Pass Guaranteed – A+ Graded
[SECTION 1: Diving Physics & Physiology — Questions 1-20]
Q1: A diver takes a flexible container filled with air from the surface (1 ATA) down to a depth of
99 feet (4 ATA). What happens to the volume of air inside the container?
A. The volume remains the same because the container is flexible.
B. The volume doubles.
C. The volume is reduced to one-fourth of the original volume. [CORRECT]
D. The volume increases by 4 times.
Correct Answer: C
Rationale: According to Boyle's Law (P1V1 = P2V2), pressure and volume are inversely
proportional for a flexible container at constant temperature. As pressure increases from 1 ATA to
4 ATA, the volume decreases to one-fourth. This principle explains why wetsuits compress and
buoyancy decreases upon descent. Flexible containers do not maintain volume like rigid
containers.
Q2: Which gas law explains why nitrogen dissolves into the diver's body tissues during a dive?
A. Boyle's Law
B. Henry's Law [CORRECT]
C. Dalton's Law
D. Charles's Law
Correct Answer: B
,2
Rationale: Henry's Law states that the amount of gas dissolved in a liquid is directly proportional
to the partial pressure of that gas above the liquid. As a diver descends, the partial pressure of
nitrogen increases, forcing more nitrogen to dissolve into the tissues (on-gassing). This absorbed
nitrogen is the primary cause of Decompression Sickness (DCS).
Q3: A diver breathing air at depth experiences an alteration in consciousness described as a
"rapturous euphoria" and impaired judgment at 100 feet. This is most likely:
A. Nitrogen Narcosis [CORRECT]
B. Oxygen Toxicity
C. Carbon Monoxide Poisoning
D. Hypothermia
Correct Answer: A
Rationale: Nitrogen Narcosis (also known as "rapture of the deep") is caused by the anesthetic
effect of nitrogen under pressure. It typically becomes noticeable around 100 feet (30 meters)
and worsens with depth. It impairs judgment and coordination, which is why deep dives require
additional training and planning. Oxygen toxicity usually manifests as convulsions.
Q4: A diver holds their breath while ascending from a dive. At 15 feet, they experience sharp
chest pain and shortness of breath. What injury has likely occurred?
A. Decompression Sickness
B. Arterial Gas Embolism (AGE) [CORRECT]
C. Middle Ear Barotrauma
D. Sinus Squeeze
Correct Answer: B
Rationale: Arterial Gas Embolism is the most serious lung overexpansion injury, caused by
expanding air in the lungs rupturing alveoli and entering the bloodstream if breath is held during
ascent. Symptoms usually appear immediately or within minutes and include chest pain,
neurological deficits, or unconsciousness. It is a life-threatening emergency requiring immediate
oxygen and transport to a hyperbaric chamber.
,3
Q5: According to Dalton's Law, if a diver is breathing a gas mixture of 32% Oxygen and 68%
Nitrogen (Nitrox32) at a depth where the ambient pressure is 4 ATA (99 feet), what is the partial
pressure of Oxygen?
A. 0.32 ATA
B. 1.00 ATA
C. 1.28 ATA [CORRECT]
D. 4.00 ATA
Correct Answer: C
Rationale: Dalton's Law states that the total pressure of a gas mixture is equal to the sum of the
partial pressures of each gas in the mixture. To find the partial pressure of Oxygen, multiply the
fraction of Oxygen (0.32) by the ambient pressure (4 ATA). Calculation: 0.32 x 4 = 1.28 ATA.
Q6: Why does a diver require more weight when diving in fresh water compared to salt water?
A. Fresh water is colder than salt water.
B. Salt water is denser than fresh water, providing more displacement. [CORRECT]
C. Fresh water is more buoyant than salt water.
D. The wetsuit compresses more in fresh water.
Correct Answer: B
Rationale: Salt water has a specific gravity of approximately 1.025, meaning it is denser than
fresh water (specific gravity 1.000). Because salt water is denser, it displaces more weight,
making a diver more buoyant. Consequently, a diver needs more lead weight to achieve proper
buoyancy in salt water than in fresh water.
Q7: A diver is planning a dive to 60 feet. Which of the following would represent the maximum
operating depth (MOD) for EANx32 if the maximum partial pressure of Oxygen (PO2) is limited
to 1.4 ATA?
A. 95 feet
, 4
B. 105 feet
C. 111 feet [CORRECT]
D. 130 feet
Correct Answer: C
Rationale: The formula for MOD is ((Maximum PO2 / Fraction of O2) - 1) x 33. For EANx32
(0.32 O2) with a max PO2 of 1.4: (1..32) - 1 = 4.375 - 1 = 3.375. Multiplying 3.375 by 33
feet per atmosphere gives approximately 111 feet. Diving deeper than this risks CNS Oxygen
Toxicity.
Q8: A diver performs a buoyancy check at the surface with an empty BCD and holds a normal
breath. They should float at which level?
A. At eye level (mask barely out of water) [CORRECT]
B. With the top of the head completely out of water
C. At the waist level
D. With fins underwater only
Correct Answer: A
Rationale: A proper buoyancy check indicates the diver is correctly weighted for the end of the
dive (when the tank is low). With a full tank, the diver will be heavy. To be correctly weighted, a
diver with a full BCD inflated and normal breath should float at eye level. If they float too high,
they are overweighted; too low, they are underweighted.
Q9: Which of the following is a symptom of Central Nervous System (CNS) Oxygen Toxicity?
A. Convulsions without warning [CORRECT]
B. Joint pain
C. Itchy skin
D. Nausea
