DIVEMASTER FINAL EXAM A
QUESTIONS AND ANSWERS 2026
1. An object is neutrally buoyant in fresh water. What will happen to the object if it is placed
in salt water?
A. It will float.
B. It will sink.
C. It will remain neutrally buoyant.
D. It will compress.
Answer: A
Conceptual Explanation: Salt water is denser than fresh water, providing more upward
buoyant force (displacement of heavier fluid) for the same volume, causing the object to
float.
2. If a diver is at 30 meters (99 feet) in salt water, what is the ambient pressure in
atmospheres absolute (ata)?
A. 3 ata
B. 2 ata
C. 5 ata
,D. 4 ata
Answer: D
Conceptual Explanation: Pressure increases by 1 ata for every 10 meters of depth in salt
water, plus 1 ata for the atmosphere at the surface. () + 1 = 4 ata.
3. According to Boyle’s Law, if the pressure on a flexible container of gas is tripled, what
happens to the volume?
A. The volume triples.
B. The volume is reduced to one-third.
C. The volume remains the same.
D. The volume is reduced to one-half.
Answer: B
Conceptual Explanation: Boyle’s Law states that pressure and volume are inversely
proportional; as pressure increases, volume decreases proportionately.
4. What is the partial pressure of oxygen (PO2) in air at a depth of 20 meters (66 feet) in salt
water?
A. 0.21 ata
B. 0.63 ata
C. 0.42 ata
D. 0.84 ata
, Answer: B
Conceptual Explanation: At 20m, the total pressure is 3 ata. Air is roughly 21% oxygen. 3
ata * 0.21 = 0.63 ata.
5. Which color is absorbed first as a diver descends into the water?
A. Blue
B. Green
C. Yellow
D. Red
Answer: D
Conceptual Explanation: Red has the longest wavelength and the lowest energy in the
visible spectrum, so it is absorbed first by water.
6. How does the speed of sound underwater compare to its speed in air?
A. Sound does not travel in water.
B. Sound travels at the same speed in both.
C. Sound travels slower in water than in air.
D. Sound travels about 4 times faster in water than in air.
Answer: D
QUESTIONS AND ANSWERS 2026
1. An object is neutrally buoyant in fresh water. What will happen to the object if it is placed
in salt water?
A. It will float.
B. It will sink.
C. It will remain neutrally buoyant.
D. It will compress.
Answer: A
Conceptual Explanation: Salt water is denser than fresh water, providing more upward
buoyant force (displacement of heavier fluid) for the same volume, causing the object to
float.
2. If a diver is at 30 meters (99 feet) in salt water, what is the ambient pressure in
atmospheres absolute (ata)?
A. 3 ata
B. 2 ata
C. 5 ata
,D. 4 ata
Answer: D
Conceptual Explanation: Pressure increases by 1 ata for every 10 meters of depth in salt
water, plus 1 ata for the atmosphere at the surface. () + 1 = 4 ata.
3. According to Boyle’s Law, if the pressure on a flexible container of gas is tripled, what
happens to the volume?
A. The volume triples.
B. The volume is reduced to one-third.
C. The volume remains the same.
D. The volume is reduced to one-half.
Answer: B
Conceptual Explanation: Boyle’s Law states that pressure and volume are inversely
proportional; as pressure increases, volume decreases proportionately.
4. What is the partial pressure of oxygen (PO2) in air at a depth of 20 meters (66 feet) in salt
water?
A. 0.21 ata
B. 0.63 ata
C. 0.42 ata
D. 0.84 ata
, Answer: B
Conceptual Explanation: At 20m, the total pressure is 3 ata. Air is roughly 21% oxygen. 3
ata * 0.21 = 0.63 ata.
5. Which color is absorbed first as a diver descends into the water?
A. Blue
B. Green
C. Yellow
D. Red
Answer: D
Conceptual Explanation: Red has the longest wavelength and the lowest energy in the
visible spectrum, so it is absorbed first by water.
6. How does the speed of sound underwater compare to its speed in air?
A. Sound does not travel in water.
B. Sound travels at the same speed in both.
C. Sound travels slower in water than in air.
D. Sound travels about 4 times faster in water than in air.
Answer: D
