DIVEMASTER FINAL EXAM A
QUESTIONS AND ANSWERS 2026
1. An object weighing 750 kg and displacing 500 liters of seawater is on the bottom. How
much air must be added to a lifting bag to make the object neutrally buoyant? (Seawater
density = 1.03 kg/L)
A. 235 liters
B. 242.7 liters
C. 228.2 liters
D. 250 liters
Answer: C
Conceptual Explanation: The weight of the water displaced by the object is 500L *
1.03kg/L = 515kg. The object weighs 750kg, so it is 235kg negative. To achieve neutral
buoyancy, you need to displace an additional 235kg of water. 235kg / 1.03kg/L = 228.155
liters.
2. If a diver breathes air at a depth of 30 meters (4 ata), what is the partial pressure of
oxygen?
A. 0.21 ata
,B. 0.42 ata
C. 0.63 ata
D. 0.84 ata
Answer: D
Conceptual Explanation: Air is 21% oxygen. At 30 meters, the total pressure is 4 ata. PO2
= 0.21 * 4 = 0.84 ata.
3. What is the primary cause of nitrogen narcosis?
A. Carbon dioxide buildup in the lungs
B. Absorption of nitrogen into the fatty tissues of the joints
C. High partial pressure of nitrogen affecting the central nervous system
D. The rapid ascent causing bubbles to form in the brain
Answer: C
Conceptual Explanation: Nitrogen narcosis is caused by the anesthetic effect of nitrogen
under high partial pressure, affecting nerve impulse transmissions.
4. Which gas law best explains why a flexible container filled with air will shrink as it is taken
deeper into the water?
A. Henry’s Law
B. Charles’ Law
, C. Boyle’s Law
D. Dalton’s Law
Answer: C
Conceptual Explanation: Boyle’s Law states that if temperature remains constant, the
volume of a gas is inversely proportional to the absolute pressure.
5. Which of the following lung overexpansion injuries involves air entering the space between
the lungs and the chest wall, causing a collapsed lung?
A. Pneumothorax
B. Mediastinal emphysema
C. Subcutaneous emphysema
D. Arterial gas embolism
Answer: A
Conceptual Explanation: Pneumothorax occurs when air escapes the lung and enters the
pleural cavity, causing the lung to collapse.
6. Sound travels ____ times faster in water than in air because water is ____ than air.
A. 2; less dense
B. 10; warmer
C. 4; denser
QUESTIONS AND ANSWERS 2026
1. An object weighing 750 kg and displacing 500 liters of seawater is on the bottom. How
much air must be added to a lifting bag to make the object neutrally buoyant? (Seawater
density = 1.03 kg/L)
A. 235 liters
B. 242.7 liters
C. 228.2 liters
D. 250 liters
Answer: C
Conceptual Explanation: The weight of the water displaced by the object is 500L *
1.03kg/L = 515kg. The object weighs 750kg, so it is 235kg negative. To achieve neutral
buoyancy, you need to displace an additional 235kg of water. 235kg / 1.03kg/L = 228.155
liters.
2. If a diver breathes air at a depth of 30 meters (4 ata), what is the partial pressure of
oxygen?
A. 0.21 ata
,B. 0.42 ata
C. 0.63 ata
D. 0.84 ata
Answer: D
Conceptual Explanation: Air is 21% oxygen. At 30 meters, the total pressure is 4 ata. PO2
= 0.21 * 4 = 0.84 ata.
3. What is the primary cause of nitrogen narcosis?
A. Carbon dioxide buildup in the lungs
B. Absorption of nitrogen into the fatty tissues of the joints
C. High partial pressure of nitrogen affecting the central nervous system
D. The rapid ascent causing bubbles to form in the brain
Answer: C
Conceptual Explanation: Nitrogen narcosis is caused by the anesthetic effect of nitrogen
under high partial pressure, affecting nerve impulse transmissions.
4. Which gas law best explains why a flexible container filled with air will shrink as it is taken
deeper into the water?
A. Henry’s Law
B. Charles’ Law
, C. Boyle’s Law
D. Dalton’s Law
Answer: C
Conceptual Explanation: Boyle’s Law states that if temperature remains constant, the
volume of a gas is inversely proportional to the absolute pressure.
5. Which of the following lung overexpansion injuries involves air entering the space between
the lungs and the chest wall, causing a collapsed lung?
A. Pneumothorax
B. Mediastinal emphysema
C. Subcutaneous emphysema
D. Arterial gas embolism
Answer: A
Conceptual Explanation: Pneumothorax occurs when air escapes the lung and enters the
pleural cavity, causing the lung to collapse.
6. Sound travels ____ times faster in water than in air because water is ____ than air.
A. 2; less dense
B. 10; warmer
C. 4; denser
