DIVEMASTER FINAL EXAM A
QUESTIONS AND ANSWERS
1. An object weighing 150 kilograms (kg) that displaces 140 liters (L) of sea water is placed in
the ocean. Which of the following is true?
A. The object will sink and weighs 5.8 kg in the water.
B. The object will float with 4.2 kg of buoyancy.
C. The object is neutrally buoyant.
D. The object will sink and weighs 10 kg in the water.
Answer: A
Conceptual Explanation: In sea water, 140L of displacement equals 144.2 kg of buoyant
force (140 * 1.03). Since the object weighs 150 kg, it is negatively buoyant by 5.8 kg.
2. According to Boyle’s Law, what happens to the density of the air inside a diver’s lungs if
they descend from the surface to 20 meters (66 feet) in the ocean?
A. The density triples.
B. The density doubles.
C. The density remains the same.
,D. The density quadruples.
Answer: A
Conceptual Explanation: At 20 meters, the total pressure is 3 atmospheres absolute (ata).
Boyle’s Law states that as pressure triples, the volume decreases to 1/3 and the density
triples.
3. If a diver consumes 20 liters of air per minute at the surface, how much air will they
consume per minute at a depth of 30 meters (99 feet)?
A. 40 liters per minute
B. 60 liters per minute
C. 100 liters per minute
D. 80 liters per minute
Answer: D
Conceptual Explanation: 30 meters is 4 ata of pressure. Surface consumption (20L)
multiplied by 4 ata equals 80L per minute.
4. Which gas law best explains the process of nitrogen dissolving into a diver’s body tissues
while under pressure?
A. Henry’s Law
B. Dalton’s Law
C. Charles’ Law
, D. Archimedes’ Principle
Answer: A
Conceptual Explanation: Henry’s Law states that the amount of gas that will dissolve into
a liquid is proportional to the partial pressure of that gas in contact with the liquid.
5. What is the partial pressure of oxygen (PO2) in Enriched Air Nitrox 32% (EANx32) at a
depth of 25 meters (82 feet) in sea water?
A. 0.32 ata
B. 0.80 ata
C. 1.40 ata
D. 1.12 ata
Answer: D
Conceptual Explanation: Depth of 25m is 3.5 ata. PO2 = 0.32 (Fraction of O2) * 3.5 ata =
1.12 ata.
6. Objects underwater appear larger and closer than they actually are. This phenomenon is
primarily caused by:
A. Diffusion
B. Absorption
C. Reflection
D. Refraction
QUESTIONS AND ANSWERS
1. An object weighing 150 kilograms (kg) that displaces 140 liters (L) of sea water is placed in
the ocean. Which of the following is true?
A. The object will sink and weighs 5.8 kg in the water.
B. The object will float with 4.2 kg of buoyancy.
C. The object is neutrally buoyant.
D. The object will sink and weighs 10 kg in the water.
Answer: A
Conceptual Explanation: In sea water, 140L of displacement equals 144.2 kg of buoyant
force (140 * 1.03). Since the object weighs 150 kg, it is negatively buoyant by 5.8 kg.
2. According to Boyle’s Law, what happens to the density of the air inside a diver’s lungs if
they descend from the surface to 20 meters (66 feet) in the ocean?
A. The density triples.
B. The density doubles.
C. The density remains the same.
,D. The density quadruples.
Answer: A
Conceptual Explanation: At 20 meters, the total pressure is 3 atmospheres absolute (ata).
Boyle’s Law states that as pressure triples, the volume decreases to 1/3 and the density
triples.
3. If a diver consumes 20 liters of air per minute at the surface, how much air will they
consume per minute at a depth of 30 meters (99 feet)?
A. 40 liters per minute
B. 60 liters per minute
C. 100 liters per minute
D. 80 liters per minute
Answer: D
Conceptual Explanation: 30 meters is 4 ata of pressure. Surface consumption (20L)
multiplied by 4 ata equals 80L per minute.
4. Which gas law best explains the process of nitrogen dissolving into a diver’s body tissues
while under pressure?
A. Henry’s Law
B. Dalton’s Law
C. Charles’ Law
, D. Archimedes’ Principle
Answer: A
Conceptual Explanation: Henry’s Law states that the amount of gas that will dissolve into
a liquid is proportional to the partial pressure of that gas in contact with the liquid.
5. What is the partial pressure of oxygen (PO2) in Enriched Air Nitrox 32% (EANx32) at a
depth of 25 meters (82 feet) in sea water?
A. 0.32 ata
B. 0.80 ata
C. 1.40 ata
D. 1.12 ata
Answer: D
Conceptual Explanation: Depth of 25m is 3.5 ata. PO2 = 0.32 (Fraction of O2) * 3.5 ata =
1.12 ata.
6. Objects underwater appear larger and closer than they actually are. This phenomenon is
primarily caused by:
A. Diffusion
B. Absorption
C. Reflection
D. Refraction
