1
PADI Open Water Final Exam A Actual Exam
2026/2027 – Complete Exam-Style Questions with
Detailed Rationales | 100% Verified | Pass
Guaranteed – A+ Graded
[SECTION 1: Diving Physics & Physiology — Questions 1-12]
Q1: What is the absolute pressure in seawater at a depth of 66 feet (20 meters)?
A. 2 ATA
B. 3 ATA
C. 4 ATA
D. 2.5 ATA
C. [Correct answer] [CORRECT]
Correct Answer: B
Rationale: To calculate absolute pressure in seawater, divide the depth by 33 feet and add 1 (for
the surface pressure). + 1 = 3 ATA. Option A is 66 ft in freshwater. Options C and D are
incorrect calculations.
Q2: According to Archimedes' principle, if you increase the buoyancy of a flexible container
(like a drysuit) while descending, what happens?
A. The container becomes heavier and sinks faster.
B. The container displaces more water, increasing buoyancy.
C. The volume of the container decreases, increasing buoyancy.
D. The container crushes due to pressure.
C. [Correct answer] [CORRECT]
Correct Answer: B
,2
Rationale: Adding air to a drysuit increases the volume of the diver/flexible container, displacing
more water and increasing buoyancy. This is why divers must add air to a drysuit to compensate
for suit compression and thermal compression. Option A refers to the suit becoming heavier due
to water infiltration, not buoyancy change.
Q3: A diver takes a breath from a scuba tank at 33 feet (2 ATA) and ascends to the surface
holding their breath. What happens to the volume of air in their lungs, and what is the risk?
A. The volume decreases by half due to pressure change; there is no risk.
B. The volume doubles due to pressure change; this can cause lung overexpansion injury.
C. The volume remains the same because the diver is holding their breath.
D. The volume increases slightly; nitrogen absorption prevents injury.
C. [Correct answer] [CORRECT]
Correct Answer: B
Rationale: According to Boyle's Law, volume is inversely proportional to pressure. As the diver
ascends from 2 ATA to 1 ATA (surface), the air volume doubles. Holding the breath causes this
expanding air to over-expand the lungs, potentially causing alveolar rupture (arterial gas
embolism or pneumothorax).
Q4: What is the most important rule to prevent lung overexpansion injuries when ascending?
A. Ascend as fast as possible to minimize nitrogen absorption.
B. Breathe continuously and never hold your breath while ascending.
C. Exhale completely at the surface to clear nitrogen.
D. Skip the safety stop if you feel good.
C. [Correct answer] [CORRECT]
Correct Answer: B
Rationale: To prevent lung overexpansion, a diver must breathe normally at all times during
ascent, allowing expanding air in the lungs to escape. Holding the breath causes the expanding
air to rupture lung tissue. Option A is dangerous as rapid ascent increases DCS risk.
, 3
Q5: A diver weighs 160 pounds with a drysuit and needs to be neutrally buoyant. Will they
require more or less weight when diving in freshwater compared to saltwater?
A. The diver will require the same amount of weight.
B. The diver will require more weight in freshwater.
C. The diver will require less weight in freshwater.
D. Freshwater diving is not recommended for drysuit divers.
C. [Correct answer] [CORRECT]
Correct Answer: B
Rationale: Freshwater is less dense than saltwater (62.4 lbs/cu ft vs 64 lbs/cu ft). Therefore, a
diver displaces less weight in freshwater and must wear more lead to achieve neutral buoyancy
than they would in saltwater. Option C is the opposite of correct physics.
Q6: As depth increases, the partial pressure of nitrogen in the breathing gas:
A. Decreases linearly.
B. Remains constant.
C. Increases.
D. Is eliminated rapidly.
C. [Correct answer] [CORRECT]
Correct Answer: C
Rationale: Since total pressure increases with depth, the partial pressure of nitrogen (PN2 = Total
Pressure x %N2 in mix) also increases. This causes more nitrogen to dissolve into the diver's
tissues, leading to no-decompression limits. Option B is incorrect because partial pressures
change with ambient pressure.
Q7: What is the primary physiological reason for following No-Decompression Limits (NDL)?
A. To prevent oxygen toxicity.
PADI Open Water Final Exam A Actual Exam
2026/2027 – Complete Exam-Style Questions with
Detailed Rationales | 100% Verified | Pass
Guaranteed – A+ Graded
[SECTION 1: Diving Physics & Physiology — Questions 1-12]
Q1: What is the absolute pressure in seawater at a depth of 66 feet (20 meters)?
A. 2 ATA
B. 3 ATA
C. 4 ATA
D. 2.5 ATA
C. [Correct answer] [CORRECT]
Correct Answer: B
Rationale: To calculate absolute pressure in seawater, divide the depth by 33 feet and add 1 (for
the surface pressure). + 1 = 3 ATA. Option A is 66 ft in freshwater. Options C and D are
incorrect calculations.
Q2: According to Archimedes' principle, if you increase the buoyancy of a flexible container
(like a drysuit) while descending, what happens?
A. The container becomes heavier and sinks faster.
B. The container displaces more water, increasing buoyancy.
C. The volume of the container decreases, increasing buoyancy.
D. The container crushes due to pressure.
C. [Correct answer] [CORRECT]
Correct Answer: B
,2
Rationale: Adding air to a drysuit increases the volume of the diver/flexible container, displacing
more water and increasing buoyancy. This is why divers must add air to a drysuit to compensate
for suit compression and thermal compression. Option A refers to the suit becoming heavier due
to water infiltration, not buoyancy change.
Q3: A diver takes a breath from a scuba tank at 33 feet (2 ATA) and ascends to the surface
holding their breath. What happens to the volume of air in their lungs, and what is the risk?
A. The volume decreases by half due to pressure change; there is no risk.
B. The volume doubles due to pressure change; this can cause lung overexpansion injury.
C. The volume remains the same because the diver is holding their breath.
D. The volume increases slightly; nitrogen absorption prevents injury.
C. [Correct answer] [CORRECT]
Correct Answer: B
Rationale: According to Boyle's Law, volume is inversely proportional to pressure. As the diver
ascends from 2 ATA to 1 ATA (surface), the air volume doubles. Holding the breath causes this
expanding air to over-expand the lungs, potentially causing alveolar rupture (arterial gas
embolism or pneumothorax).
Q4: What is the most important rule to prevent lung overexpansion injuries when ascending?
A. Ascend as fast as possible to minimize nitrogen absorption.
B. Breathe continuously and never hold your breath while ascending.
C. Exhale completely at the surface to clear nitrogen.
D. Skip the safety stop if you feel good.
C. [Correct answer] [CORRECT]
Correct Answer: B
Rationale: To prevent lung overexpansion, a diver must breathe normally at all times during
ascent, allowing expanding air in the lungs to escape. Holding the breath causes the expanding
air to rupture lung tissue. Option A is dangerous as rapid ascent increases DCS risk.
, 3
Q5: A diver weighs 160 pounds with a drysuit and needs to be neutrally buoyant. Will they
require more or less weight when diving in freshwater compared to saltwater?
A. The diver will require the same amount of weight.
B. The diver will require more weight in freshwater.
C. The diver will require less weight in freshwater.
D. Freshwater diving is not recommended for drysuit divers.
C. [Correct answer] [CORRECT]
Correct Answer: B
Rationale: Freshwater is less dense than saltwater (62.4 lbs/cu ft vs 64 lbs/cu ft). Therefore, a
diver displaces less weight in freshwater and must wear more lead to achieve neutral buoyancy
than they would in saltwater. Option C is the opposite of correct physics.
Q6: As depth increases, the partial pressure of nitrogen in the breathing gas:
A. Decreases linearly.
B. Remains constant.
C. Increases.
D. Is eliminated rapidly.
C. [Correct answer] [CORRECT]
Correct Answer: C
Rationale: Since total pressure increases with depth, the partial pressure of nitrogen (PN2 = Total
Pressure x %N2 in mix) also increases. This causes more nitrogen to dissolve into the diver's
tissues, leading to no-decompression limits. Option B is incorrect because partial pressures
change with ambient pressure.
Q7: What is the primary physiological reason for following No-Decompression Limits (NDL)?
A. To prevent oxygen toxicity.
