Page 1 of 165
PADI Open Water Final Exam B Actual Exam
2026/2027 – Complete Exam-Style Questions
with Detailed Rationales | 100% Verified |
Pass Guaranteed – A+ Graded
Question 1
Scenario: A diver descends from the surface to 10 meters (33
feet). The ambient pressure increases from 1 atmosphere to 2
atmospheres absolute (ATA). What happens to the volume of a
flexible air-filled space (e.g., a diver’s lungs, a balloon)?
A) It doubles
B) It is reduced to one-half
C) It remains the same
D) It increases by 50%
Answer: B
,Page 2 of 165
Rationale: Boyle’s law states that at constant temperature, the
volume of a gas is inversely proportional surface volume.to the
absolute pressure. At 10 m, pressure is 2 ATA (1 atm from water
+ 1 atm from atmosphere). Volume = 1/2 of
Question 2
If a diver descends to 20 meters (66 feet), the ambient pressure
is:
A) 2 ATA
B) 3 ATA
C) 4 ATA
D) 1 ATA
Answer: B
,Page 3 of 165
Rationale: Every 10 meters of seawater = 1 atmosphere of
pressure. At 20 m, water pressure = 2 ATA, plus 1 ATA surface
atmosphere = 3 ATA total.
Question 3
Scenario: A diver takes a full breath of air from a scuba
regulator at 30 meters (99 feet). The pressure at that depth is 4
ATA. If the diver holds his breath and ascends to the surface (1
ATA), the air in his lungs would expand to how many times its
original volume?
A) 2 times
B) 3 times
C) 4 times
D) 8 times
Answer: C
, Page 4 of 165
Rationale: Volume is inversely proportional to pressure. At 30 m,
pressure = 4 ATA. At surface, pressure = 1 ATA. Volume
increases by factor = 4/1 = 4 times. This can cause lung
overexpansion injury. Never hold your breath while ascending.
Question 4
The absolute pressure at 40 meters (132 feet) of seawater is:
A) 4 ATA
B) 5 ATA
C) 6 ATA
D) 3 ATA
Answer: B
Rationale: 40 m water pressure = 4 ATA; plus surface 1 ATA =
5 ATA.
PADI Open Water Final Exam B Actual Exam
2026/2027 – Complete Exam-Style Questions
with Detailed Rationales | 100% Verified |
Pass Guaranteed – A+ Graded
Question 1
Scenario: A diver descends from the surface to 10 meters (33
feet). The ambient pressure increases from 1 atmosphere to 2
atmospheres absolute (ATA). What happens to the volume of a
flexible air-filled space (e.g., a diver’s lungs, a balloon)?
A) It doubles
B) It is reduced to one-half
C) It remains the same
D) It increases by 50%
Answer: B
,Page 2 of 165
Rationale: Boyle’s law states that at constant temperature, the
volume of a gas is inversely proportional surface volume.to the
absolute pressure. At 10 m, pressure is 2 ATA (1 atm from water
+ 1 atm from atmosphere). Volume = 1/2 of
Question 2
If a diver descends to 20 meters (66 feet), the ambient pressure
is:
A) 2 ATA
B) 3 ATA
C) 4 ATA
D) 1 ATA
Answer: B
,Page 3 of 165
Rationale: Every 10 meters of seawater = 1 atmosphere of
pressure. At 20 m, water pressure = 2 ATA, plus 1 ATA surface
atmosphere = 3 ATA total.
Question 3
Scenario: A diver takes a full breath of air from a scuba
regulator at 30 meters (99 feet). The pressure at that depth is 4
ATA. If the diver holds his breath and ascends to the surface (1
ATA), the air in his lungs would expand to how many times its
original volume?
A) 2 times
B) 3 times
C) 4 times
D) 8 times
Answer: C
, Page 4 of 165
Rationale: Volume is inversely proportional to pressure. At 30 m,
pressure = 4 ATA. At surface, pressure = 1 ATA. Volume
increases by factor = 4/1 = 4 times. This can cause lung
overexpansion injury. Never hold your breath while ascending.
Question 4
The absolute pressure at 40 meters (132 feet) of seawater is:
A) 4 ATA
B) 5 ATA
C) 6 ATA
D) 3 ATA
Answer: B
Rationale: 40 m water pressure = 4 ATA; plus surface 1 ATA =
5 ATA.
