1
PADI Open Water Final Exam B 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: According to Boyle's Law, if you take a flexible container filled with air at the surface (1
ATA) down to 33 feet (2 ATA) of seawater, what happens to the volume of the air inside the
container?
A. The volume doubles.
B. The volume remains the same.
C. The volume is reduced to one-half of its original volume.
D. The volume is reduced to one-third of its original volume.
Correct Answer: C
Rationale: Boyle's Law states that pressure and volume are inversely proportional; as pressure
increases, volume decreases. At 33 feet (10 meters) of seawater, the ambient pressure is 2
atmospheres absolute (ATA). Therefore, the volume of gas is reduced by half (1/2) to maintain
equilibrium. Option A describes the reverse (ascending), and D describes a depth of 66 feet (3
ATA).
Q2: A diver experiences a squeezing sensation and pain in their mask while descending. This is
caused by:
A. Nitrogen narcosis.
B. Mask squeeze due to the inability to equalize the air space inside the mask.
C. The increased water pressure compressing the air space inside the mask.
D. Too much air in the mask.
Correct Answer: C
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Rationale: As a diver descends, water pressure increases, compressing the air space inside the
mask. If the diver does not exhale into the mask to add air and equalize the pressure, the mask
sucks against the face, causing pain and potential bruising. Nitrogen narcosis is a mental effect,
not physical squeeze.
Q3: While ascending, a diver holds their breath. What is the most likely consequence?
A. Decompression sickness.
B. Nitrogen narcosis.
C. Lung overexpansion injury.
D. Shallow water blackout.
Correct Answer: C
Rationale: According to Boyle's Law, air expands as pressure decreases during an ascent. If a
diver holds their breath, the expanding air can rupture lung tissue (lung overexpansion injury),
leading to arterial gas embolism. Decompression sickness is caused by nitrogen bubbles forming
from dissolved gas, not simply holding breath.
Q4: At what depth does a diver typically begin to feel the effects of nitrogen narcosis (the
"rapture of the deep")?
A. 20 feet (6 meters)
B. 50 feet (15 meters)
C. 100 feet (30 meters)
D. 150 feet (45 meters)
Correct Answer: C
Rationale: While nitrogen narcosis can affect divers at shallower depths, symptoms such as
euphoria, impaired judgment, and a feeling of intoxication typically become noticeable and
significant around 100 feet (30 meters). The condition is caused by the partial pressure of
nitrogen at depth.
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Q5: What is the primary physiological cause of Decompression Sickness (DCS)?
A. Nitrogen narcosis.
B. Hyperventilation.
C. Nitrogen coming out of solution and forming bubbles in the bloodstream and tissues.
D. Carbon dioxide buildup.
Correct Answer: C
Rationale: DCS occurs when a diver ascends too quickly, causing the nitrogen dissolved in the
body tissues to come out of solution faster than the body can eliminate it through respiration.
This results in bubbles forming in the bloodstream and tissues, causing pain and neurological
symptoms. Hyperventilation leads to shallow water blackout, not DCS.
Q6: Which method is the standard technique for equalizing the pressure in the ears and sinuses
during a descent?
A. Panting like a dog.
B. Exhaling into the mask.
C. The Valsalva maneuver (pinching the nose and blowing gently against it).
D. Holding the breath and swallowing.
Correct Answer: C
Rationale: The Valsalva maneuver is the primary technique used to equalize pressure in the
middle ear. By pinching the nose closed and gently exhaling against it, air is forced through the
Eustachian tubes to equalize the pressure on both sides of the eardrum. Swallowing can also
help, but Valsalva is the taught standard method.
Q7: How does sound travel underwater compared to air?
A. Sound travels slower and is harder to hear.
B. Sound travels at the exact same speed and intensity.
C. Sound travels about four times faster underwater.
PADI Open Water Final Exam B 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: According to Boyle's Law, if you take a flexible container filled with air at the surface (1
ATA) down to 33 feet (2 ATA) of seawater, what happens to the volume of the air inside the
container?
A. The volume doubles.
B. The volume remains the same.
C. The volume is reduced to one-half of its original volume.
D. The volume is reduced to one-third of its original volume.
Correct Answer: C
Rationale: Boyle's Law states that pressure and volume are inversely proportional; as pressure
increases, volume decreases. At 33 feet (10 meters) of seawater, the ambient pressure is 2
atmospheres absolute (ATA). Therefore, the volume of gas is reduced by half (1/2) to maintain
equilibrium. Option A describes the reverse (ascending), and D describes a depth of 66 feet (3
ATA).
Q2: A diver experiences a squeezing sensation and pain in their mask while descending. This is
caused by:
A. Nitrogen narcosis.
B. Mask squeeze due to the inability to equalize the air space inside the mask.
C. The increased water pressure compressing the air space inside the mask.
D. Too much air in the mask.
Correct Answer: C
,2
Rationale: As a diver descends, water pressure increases, compressing the air space inside the
mask. If the diver does not exhale into the mask to add air and equalize the pressure, the mask
sucks against the face, causing pain and potential bruising. Nitrogen narcosis is a mental effect,
not physical squeeze.
Q3: While ascending, a diver holds their breath. What is the most likely consequence?
A. Decompression sickness.
B. Nitrogen narcosis.
C. Lung overexpansion injury.
D. Shallow water blackout.
Correct Answer: C
Rationale: According to Boyle's Law, air expands as pressure decreases during an ascent. If a
diver holds their breath, the expanding air can rupture lung tissue (lung overexpansion injury),
leading to arterial gas embolism. Decompression sickness is caused by nitrogen bubbles forming
from dissolved gas, not simply holding breath.
Q4: At what depth does a diver typically begin to feel the effects of nitrogen narcosis (the
"rapture of the deep")?
A. 20 feet (6 meters)
B. 50 feet (15 meters)
C. 100 feet (30 meters)
D. 150 feet (45 meters)
Correct Answer: C
Rationale: While nitrogen narcosis can affect divers at shallower depths, symptoms such as
euphoria, impaired judgment, and a feeling of intoxication typically become noticeable and
significant around 100 feet (30 meters). The condition is caused by the partial pressure of
nitrogen at depth.
, 3
Q5: What is the primary physiological cause of Decompression Sickness (DCS)?
A. Nitrogen narcosis.
B. Hyperventilation.
C. Nitrogen coming out of solution and forming bubbles in the bloodstream and tissues.
D. Carbon dioxide buildup.
Correct Answer: C
Rationale: DCS occurs when a diver ascends too quickly, causing the nitrogen dissolved in the
body tissues to come out of solution faster than the body can eliminate it through respiration.
This results in bubbles forming in the bloodstream and tissues, causing pain and neurological
symptoms. Hyperventilation leads to shallow water blackout, not DCS.
Q6: Which method is the standard technique for equalizing the pressure in the ears and sinuses
during a descent?
A. Panting like a dog.
B. Exhaling into the mask.
C. The Valsalva maneuver (pinching the nose and blowing gently against it).
D. Holding the breath and swallowing.
Correct Answer: C
Rationale: The Valsalva maneuver is the primary technique used to equalize pressure in the
middle ear. By pinching the nose closed and gently exhaling against it, air is forced through the
Eustachian tubes to equalize the pressure on both sides of the eardrum. Swallowing can also
help, but Valsalva is the taught standard method.
Q7: How does sound travel underwater compared to air?
A. Sound travels slower and is harder to hear.
B. Sound travels at the exact same speed and intensity.
C. Sound travels about four times faster underwater.
