PADI OPEN WATER FINAL EXAM A
QUESTIONS AND CORRECT ANSWERS
(VERIFIED ANSWERS) PLUS RATIONALES
2026 Q&A |LATEST EXAM UPDATE
2026/2027.
Question 1: If an object is neutrally buoyant (does not sink or float) in fresh water,
the same object placed into salt water would:
• A. Sink
• B. Either sink or float
• C. Do nothing
• D. Float
Correct Answer: D
Rationale: Salt water is denser (approximately 1025 kg/m³) than fresh water (1000
kg/m³). The increased density provides greater buoyant force, causing the neutrally
buoyant object to float in salt water.
Question 2: If an object is neutrally buoyant in salt water, what will happen when
placed in fresh water?
• A. It will float
• B. It will sink
• C. It will remain neutrally buoyant
, • D. It will oscillate
Correct Answer: B
Rationale: Fresh water is less dense than salt water, providing less buoyant force. A
neutrally buoyant object in salt water will sink in fresh water.
Question 3: A scuba cylinder contains 200 bar of air at 20°C. If the temperature
drops to 10°C, what happens to the pressure inside the cylinder (assuming
constant volume)?
• A. It increases
• B. It decreases
• C. It stays the same
• D. It doubles
Correct Answer: B
Rationale: According to Gay-Lussac's Law (P₁/T₁ = P₂/T₂ at constant volume),
pressure is directly proportional to absolute temperature. A decrease in
temperature causes a decrease in pressure.
Question 4: A diver at 10 meters (33 feet) in salt water experiences an absolute
pressure of:
• A. 1 atm
• B. 2 atm
• C. 3 atm
, • D. 4 atm
Correct Answer: B
Rationale: At 10 meters in salt water, the hydrostatic pressure is 1 atm (from the
water) plus 1 atm (atmospheric) = 2 atm absolute. Every 10 meters of salt water
adds approximately 1 atm of pressure.
Question 5: If a diver descends from 10 meters to 30 meters, the pressure changes
from:
• A. 1 atm to 3 atm
• B. 2 atm to 4 atm
• C. 3 atm to 5 atm
• D. 2 atm to 3 atm
Correct Answer: B
Rationale: At 10 meters, pressure = 2 atm (1 atm atmospheric + 1 atm water). At 30
meters, pressure = 4 atm (1 atm atmospheric + 3 atm water).
Question 6: According to Boyle's Law, if the pressure on a gas doubles, the volume
will:
• A. Double
• B. Remain the same
• C. Halve
• D. Quadruple
, Correct Answer: C
Rationale: Boyle's Law states that at constant temperature, the volume of a gas is
inversely proportional to its pressure (P₁V₁ = P₂V₂). If pressure doubles, volume
halves.
Question 7: A balloon filled with air at the surface is taken to 20 meters of depth.
The volume of the balloon will be approximately:
• A. One-third of its surface volume
• B. One-half of its surface volume
• C. Two-thirds of its surface volume
• D. The same as at the surface
Correct Answer: A
Rationale: At 20 meters, absolute pressure is 3 atm (1 atm surface + 2 atm water).
According to Boyle's Law, volume = surface volume ÷ 3, or approximately one-third
of its surface volume.
Question 8: The pressure exerted by a column of seawater is approximately:
• A. 0.445 psi per foot
• B. 0.432 psi per foot
• C. 0.445 atm per foot
• D. 0.432 atm per meter
Correct Answer: A
QUESTIONS AND CORRECT ANSWERS
(VERIFIED ANSWERS) PLUS RATIONALES
2026 Q&A |LATEST EXAM UPDATE
2026/2027.
Question 1: If an object is neutrally buoyant (does not sink or float) in fresh water,
the same object placed into salt water would:
• A. Sink
• B. Either sink or float
• C. Do nothing
• D. Float
Correct Answer: D
Rationale: Salt water is denser (approximately 1025 kg/m³) than fresh water (1000
kg/m³). The increased density provides greater buoyant force, causing the neutrally
buoyant object to float in salt water.
Question 2: If an object is neutrally buoyant in salt water, what will happen when
placed in fresh water?
• A. It will float
• B. It will sink
• C. It will remain neutrally buoyant
, • D. It will oscillate
Correct Answer: B
Rationale: Fresh water is less dense than salt water, providing less buoyant force. A
neutrally buoyant object in salt water will sink in fresh water.
Question 3: A scuba cylinder contains 200 bar of air at 20°C. If the temperature
drops to 10°C, what happens to the pressure inside the cylinder (assuming
constant volume)?
• A. It increases
• B. It decreases
• C. It stays the same
• D. It doubles
Correct Answer: B
Rationale: According to Gay-Lussac's Law (P₁/T₁ = P₂/T₂ at constant volume),
pressure is directly proportional to absolute temperature. A decrease in
temperature causes a decrease in pressure.
Question 4: A diver at 10 meters (33 feet) in salt water experiences an absolute
pressure of:
• A. 1 atm
• B. 2 atm
• C. 3 atm
, • D. 4 atm
Correct Answer: B
Rationale: At 10 meters in salt water, the hydrostatic pressure is 1 atm (from the
water) plus 1 atm (atmospheric) = 2 atm absolute. Every 10 meters of salt water
adds approximately 1 atm of pressure.
Question 5: If a diver descends from 10 meters to 30 meters, the pressure changes
from:
• A. 1 atm to 3 atm
• B. 2 atm to 4 atm
• C. 3 atm to 5 atm
• D. 2 atm to 3 atm
Correct Answer: B
Rationale: At 10 meters, pressure = 2 atm (1 atm atmospheric + 1 atm water). At 30
meters, pressure = 4 atm (1 atm atmospheric + 3 atm water).
Question 6: According to Boyle's Law, if the pressure on a gas doubles, the volume
will:
• A. Double
• B. Remain the same
• C. Halve
• D. Quadruple
, Correct Answer: C
Rationale: Boyle's Law states that at constant temperature, the volume of a gas is
inversely proportional to its pressure (P₁V₁ = P₂V₂). If pressure doubles, volume
halves.
Question 7: A balloon filled with air at the surface is taken to 20 meters of depth.
The volume of the balloon will be approximately:
• A. One-third of its surface volume
• B. One-half of its surface volume
• C. Two-thirds of its surface volume
• D. The same as at the surface
Correct Answer: A
Rationale: At 20 meters, absolute pressure is 3 atm (1 atm surface + 2 atm water).
According to Boyle's Law, volume = surface volume ÷ 3, or approximately one-third
of its surface volume.
Question 8: The pressure exerted by a column of seawater is approximately:
• A. 0.445 psi per foot
• B. 0.432 psi per foot
• C. 0.445 atm per foot
• D. 0.432 atm per meter
Correct Answer: A
