NAUI FINAL TEST REVIEW – QUESTIONS AND ANSWERS | VERIFIED AND WELL DETAILED ANSWERS
| PLUS RATIONALES | GUARANTEED PASS | LATEST EXAM UPDATE
Core Domains:
1. Diving Physics and Physiology
2. Dive Equipment and Technology
3. Dive Planning and Environment
4. Decompression Theory and Tables
5. Emergency Procedures and First Aid
6. NAUI Standards and Operational Procedures
7. Marine Ecology and Hazardous Marine Life
8. Navigation and Search Patterns
9. Specialized Diving Activities (e.g., Night, Deep, Wreck)
10. Professional Ethics and Responsibilities
Introduction:
This comprehensive assessment is designed to rigorously evaluate a candidate's mastery of the
knowledge required for the NAUI final examination. It covers a broad spectrum of topics, from
fundamental physical laws governing the underwater world to the practical application of dive planning,
decompression management, and emergency response. The exam utilizes a multiple-choice and
scenario-based format to test not only rote memorization but also critical thinking, decision-making
skills, and the application of theoretical knowledge to real-world diving situations. Successful completion
of this review indicates a high level of preparedness and a commitment to the safety standards and
professional ethics central to the NAUI philosophy.
Section One: Questions 1 – 100
1. According to Boyle's Law, if a diver descends from the surface to a depth of 33 feet in seawater,
the volume of a given amount of gas will:
A. Increase to twice its original volume.
B. Remain the same as the pressure is constant.
C. Decrease to one-half its original volume.
D. Decrease to one-third its original volume.
🟢 C. Decrease to one-half its original volume.
🔴 Explanation: Boyle's Law states that at a constant temperature, the volume of a gas is inversely
proportional to its pressure. At a depth of 33 feet in seawater, the absolute pressure is 2 atmospheres
(ATA). The volume will therefore be 1/2 of its original surface volume.
2. The partial pressure of oxygen in a diver's breathing gas is a critical factor in preventing oxygen
toxicity. If a diver is breathing air (21% O2) at a depth of 66 feet of seawater (3 ATA), what is the
PO2?
A. 0.21 ATA
B. 0.42 ATA
,C. 0.63 ATA
D. 2.10 ATA
🟢 C. 0.63 ATA
🔴 Explanation: The partial pressure of a gas is calculated by multiplying its fraction by the total
absolute pressure. At 66 feet, the total pressure is 3 ATA. Therefore, PO2 = 0.21 x 3 = 0.63 ATA.
3. A diver is planning a dive to 80 feet for 25 minutes. The surface interval before the dive is 2
hours. What is the Residual Nitrogen Time (RNT) for this dive, assuming the diver is using NAUI
tables and has a previous dive to 60 feet for 30 minutes?
A. 0 minutes
B. 15 minutes
C. 30 minutes
D. 45 minutes
🟢 C. 30 minutes
🔴 Explanation: Using the NAUI dive tables, after a surface interval of 2 hours, the diver's pressure
group is determined. The RNT is the amount of nitrogen time from the previous dive that must be
considered as part of the new dive. Based on the specific table, the RNT for this scenario is 30 minutes.
4. The mechanism of injury for an arterial gas embolism (AGE) is:
A. Nitrogen bubbles blocking blood flow in the pulmonary capillaries.
B. The expansion of air trapped in a lung overexpansion injury, forcing bubbles into the arterial
circulation.
C. The formation of nitrogen bubbles in the tissues due to a rapid ascent.
D. A blockage of an artery by a piece of atherosclerotic plaque.
🟢 B. The expansion of air trapped in a lung overexpansion injury, forcing bubbles into the arterial
circulation.
🔴 Explanation: An AGE occurs when gas bubbles enter the arterial system, typically as a result of a
pulmonary barotrauma. The expanding gas in the lungs ruptures the alveolar walls and enters the
pulmonary veins, traveling to the left side of the heart and into the arterial circulation where it can
lodge in the brain or other organs.
5. A diver with a current pressure group of "K" plans a repetitive dive to 70 feet. Using the NAUI
tables, what is the maximum allowable bottom time for this dive?
A. 15 minutes
B. 20 minutes
C. 25 minutes
D. 30 minutes
🟢 C. 25 minutes
🔴 Explanation: The maximum allowable bottom time for a repetitive dive is determined by locating
the residual nitrogen time (RNT) for the new depth based on the current pressure group and
subtracting it from the No-Decompression Limit (NDL) for that depth. For a pressure group K at 70
feet, the RNT is 25 minutes, and the NDL is 50 minutes, allowing a bottom time of 25 minutes.
, 6. What is the primary function of the demand regulator's first stage?
A. To reduce the high-pressure air from the cylinder to an intermediate pressure.
B. To deliver air to the diver on demand at ambient pressure.
C. To provide a visual indication of the remaining cylinder pressure.
D. To filter out moisture and impurities from the breathing air.
🟢 A. To reduce the high-pressure air from the cylinder to an intermediate pressure.
🔴 Explanation: The first stage of a scuba regulator is designed to reduce the high pressure from the
scuba cylinder (typically 3000 psi) to an intermediate pressure (around 135 psi) that is delivered to the
second stage via the hose. The second stage then regulates this air to ambient pressure for the diver.
7. The most important characteristic of a properly fitted mask is:
A. Tempered glass lenses.
B. A comfortable strap.
C. A low internal volume.
D. A watertight seal.
🟢 D. A watertight seal.
🔴 Explanation: While all options are important features, the primary function of a dive mask is to
create a watertight air space in front of the diver's eyes to allow for clear vision underwater. A proper
seal is paramount for this function.
8. What is the purpose of the alternate air source (octopus) during a dive?
A. To provide a backup regulator for the primary regulator.
B. To allow a buddy to share air in an out-of-air emergency.
C. To provide a source of air for a diver who has become entangled.
D. To connect to a surface-supplied air system.
🟢 B. To allow a buddy to share air in an out-of-air emergency.
🔴 Explanation: The alternate air source, often a second stage on a long hose, is specifically intended
as a redundant breathing supply for both the diver and their buddy in an emergency where the
primary regulator fails or a diver runs out of air.
9. A diver experiences a sudden, sharp chest pain, shortness of breath, and coughing up blood-
stained sputum immediately after a rapid ascent. These symptoms are most indicative of:
A. Decompression Sickness (DCS) Type I.
B. A ruptured eardrum.
C. Pulmonary overexpansion injury.
D. Nitrogen narcosis.
🟢 C. Pulmonary overexpansion injury.
🔴 Explanation: These symptoms are classic signs of a pulmonary barotrauma. The rapid ascent causes
trapped air in the lungs to expand, rupturing the alveoli and causing hemorrhage into the lung tissues,
leading to chest pain, hemoptysis (blood-stained sputum), and dyspnea (shortness of breath).
10. The maximum depth for a diver using standard air as a breathing gas without an increased risk
of oxygen toxicity is generally considered to be:
A. 100 feet
| PLUS RATIONALES | GUARANTEED PASS | LATEST EXAM UPDATE
Core Domains:
1. Diving Physics and Physiology
2. Dive Equipment and Technology
3. Dive Planning and Environment
4. Decompression Theory and Tables
5. Emergency Procedures and First Aid
6. NAUI Standards and Operational Procedures
7. Marine Ecology and Hazardous Marine Life
8. Navigation and Search Patterns
9. Specialized Diving Activities (e.g., Night, Deep, Wreck)
10. Professional Ethics and Responsibilities
Introduction:
This comprehensive assessment is designed to rigorously evaluate a candidate's mastery of the
knowledge required for the NAUI final examination. It covers a broad spectrum of topics, from
fundamental physical laws governing the underwater world to the practical application of dive planning,
decompression management, and emergency response. The exam utilizes a multiple-choice and
scenario-based format to test not only rote memorization but also critical thinking, decision-making
skills, and the application of theoretical knowledge to real-world diving situations. Successful completion
of this review indicates a high level of preparedness and a commitment to the safety standards and
professional ethics central to the NAUI philosophy.
Section One: Questions 1 – 100
1. According to Boyle's Law, if a diver descends from the surface to a depth of 33 feet in seawater,
the volume of a given amount of gas will:
A. Increase to twice its original volume.
B. Remain the same as the pressure is constant.
C. Decrease to one-half its original volume.
D. Decrease to one-third its original volume.
🟢 C. Decrease to one-half its original volume.
🔴 Explanation: Boyle's Law states that at a constant temperature, the volume of a gas is inversely
proportional to its pressure. At a depth of 33 feet in seawater, the absolute pressure is 2 atmospheres
(ATA). The volume will therefore be 1/2 of its original surface volume.
2. The partial pressure of oxygen in a diver's breathing gas is a critical factor in preventing oxygen
toxicity. If a diver is breathing air (21% O2) at a depth of 66 feet of seawater (3 ATA), what is the
PO2?
A. 0.21 ATA
B. 0.42 ATA
,C. 0.63 ATA
D. 2.10 ATA
🟢 C. 0.63 ATA
🔴 Explanation: The partial pressure of a gas is calculated by multiplying its fraction by the total
absolute pressure. At 66 feet, the total pressure is 3 ATA. Therefore, PO2 = 0.21 x 3 = 0.63 ATA.
3. A diver is planning a dive to 80 feet for 25 minutes. The surface interval before the dive is 2
hours. What is the Residual Nitrogen Time (RNT) for this dive, assuming the diver is using NAUI
tables and has a previous dive to 60 feet for 30 minutes?
A. 0 minutes
B. 15 minutes
C. 30 minutes
D. 45 minutes
🟢 C. 30 minutes
🔴 Explanation: Using the NAUI dive tables, after a surface interval of 2 hours, the diver's pressure
group is determined. The RNT is the amount of nitrogen time from the previous dive that must be
considered as part of the new dive. Based on the specific table, the RNT for this scenario is 30 minutes.
4. The mechanism of injury for an arterial gas embolism (AGE) is:
A. Nitrogen bubbles blocking blood flow in the pulmonary capillaries.
B. The expansion of air trapped in a lung overexpansion injury, forcing bubbles into the arterial
circulation.
C. The formation of nitrogen bubbles in the tissues due to a rapid ascent.
D. A blockage of an artery by a piece of atherosclerotic plaque.
🟢 B. The expansion of air trapped in a lung overexpansion injury, forcing bubbles into the arterial
circulation.
🔴 Explanation: An AGE occurs when gas bubbles enter the arterial system, typically as a result of a
pulmonary barotrauma. The expanding gas in the lungs ruptures the alveolar walls and enters the
pulmonary veins, traveling to the left side of the heart and into the arterial circulation where it can
lodge in the brain or other organs.
5. A diver with a current pressure group of "K" plans a repetitive dive to 70 feet. Using the NAUI
tables, what is the maximum allowable bottom time for this dive?
A. 15 minutes
B. 20 minutes
C. 25 minutes
D. 30 minutes
🟢 C. 25 minutes
🔴 Explanation: The maximum allowable bottom time for a repetitive dive is determined by locating
the residual nitrogen time (RNT) for the new depth based on the current pressure group and
subtracting it from the No-Decompression Limit (NDL) for that depth. For a pressure group K at 70
feet, the RNT is 25 minutes, and the NDL is 50 minutes, allowing a bottom time of 25 minutes.
, 6. What is the primary function of the demand regulator's first stage?
A. To reduce the high-pressure air from the cylinder to an intermediate pressure.
B. To deliver air to the diver on demand at ambient pressure.
C. To provide a visual indication of the remaining cylinder pressure.
D. To filter out moisture and impurities from the breathing air.
🟢 A. To reduce the high-pressure air from the cylinder to an intermediate pressure.
🔴 Explanation: The first stage of a scuba regulator is designed to reduce the high pressure from the
scuba cylinder (typically 3000 psi) to an intermediate pressure (around 135 psi) that is delivered to the
second stage via the hose. The second stage then regulates this air to ambient pressure for the diver.
7. The most important characteristic of a properly fitted mask is:
A. Tempered glass lenses.
B. A comfortable strap.
C. A low internal volume.
D. A watertight seal.
🟢 D. A watertight seal.
🔴 Explanation: While all options are important features, the primary function of a dive mask is to
create a watertight air space in front of the diver's eyes to allow for clear vision underwater. A proper
seal is paramount for this function.
8. What is the purpose of the alternate air source (octopus) during a dive?
A. To provide a backup regulator for the primary regulator.
B. To allow a buddy to share air in an out-of-air emergency.
C. To provide a source of air for a diver who has become entangled.
D. To connect to a surface-supplied air system.
🟢 B. To allow a buddy to share air in an out-of-air emergency.
🔴 Explanation: The alternate air source, often a second stage on a long hose, is specifically intended
as a redundant breathing supply for both the diver and their buddy in an emergency where the
primary regulator fails or a diver runs out of air.
9. A diver experiences a sudden, sharp chest pain, shortness of breath, and coughing up blood-
stained sputum immediately after a rapid ascent. These symptoms are most indicative of:
A. Decompression Sickness (DCS) Type I.
B. A ruptured eardrum.
C. Pulmonary overexpansion injury.
D. Nitrogen narcosis.
🟢 C. Pulmonary overexpansion injury.
🔴 Explanation: These symptoms are classic signs of a pulmonary barotrauma. The rapid ascent causes
trapped air in the lungs to expand, rupturing the alveoli and causing hemorrhage into the lung tissues,
leading to chest pain, hemoptysis (blood-stained sputum), and dyspnea (shortness of breath).
10. The maximum depth for a diver using standard air as a breathing gas without an increased risk
of oxygen toxicity is generally considered to be:
A. 100 feet
