PADI Open Water Diver Certification| Final
Knowledge Assessment Practice 2026 | All
Questions And Answers | Exam Prep
As pressure increases on a gas volume, what happens to the density of the gas and its
volume? ANSWER: The volume decreases and the density increases.
If a flexible air-filled container has a volume of 6 liters at the surface, what will its
volume be at a depth of 20 meters (66 feet) in salt water? ANSWER: 2 liters.
What is the pressure in atmospheres absolute (ata) at a depth of 30 meters (99 feet)
in salt water? ANSWER: 4 ata.
Why must a diver equalizing their air spaces do so gently and frequently during
descent? ANSWER: To prevent barotrauma and discomfort before pressure differences
become significant.
What is the most important rule in scuba diving regarding breathing during descent,
bottom time, and ascent? ANSWER: Breathe continuously and never hold your breath.
What is the primary cause of an air embolism or pulmonary barotrauma during
ascent? ANSWER: Holding breath while ascending, causing expanding air to rupture lung
tissues.
If a diver feels ear discomfort during descent, what is the immediate and correct
action to take? ANSWER: Stop descent, ascend slightly until the pressure/discomfort
relieves, equalize, and then continue descending slowly.
How does salt water differ from fresh water in terms of weight per unit volume and
buoyancy force exerted? ANSWER: Salt water is heavier per unit volume and provides
more buoyant force than fresh water.
A diver neutrally buoyant in fresh water enters salt water with the exact same
equipment configuration. What change in buoyancy will occur? ANSWER: The diver
will become positively buoyant.
What total weight adjustment is necessary if a diver switches from a 3 mm shorty
wetsuit to a 7 mm full wetsuit with hood and gloves? ANSWER: Add weight to
compensate for the additional buoyancy of the thicker neoprene.
,Which piece of equipment provides a secondary air source intended for sharing air
with a buddy in an emergency? ANSWER: Alternate air source / Octopus.
What is the primary function of the first stage of a scuba regulator? ANSWER: To
reduce high pressure from the scuba cylinder to an intermediate pressure above ambient
pressure.
How does a diver maintain proper cylinder buoyancy balance as compressed gas is
consumed throughout a dive? ANSWER: By using a BCD low-pressure inflator to adjust
buoyancy as the cylinder becomes lighter.
When reading a submersible pressure gauge (SPG), when should a diver plan to
begin their ascent to the surface? ANSWER: Before reaching the planned reserve pressure
limit established during pre-dive planning.
What is the purpose of the burst disk integrated into a scuba cylinder valve
assembly? ANSWER: To safely vent excessive pressure if the cylinder is overfilled or exposed
to extreme heat.
What visual indicator or marking on an aluminum scuba cylinder indicates it has
passed an annual inspection? ANSWER: A current visual inspection decal (VIP sticker)
applied by a qualified technician.
How often must a scuba cylinder undergo hydrostatic pressure testing under
standard international regulations? ANSWER: Every 5 years.
What is the result of breathing cold, dry compressed air from a scuba cylinder on a
diver's body temperature and hydration? ANSWER: It causes internal heat loss and
promotes dehydration.
Why should a scuba cylinder never be emptied completely to zero pressure during
storage? ANSWER: To prevent moisture and environmental contaminants from entering the
interior of the cylinder.
What type of valve mechanism remains open if an air supply system is connected and
turned on, but automatically seals if disconnected? ANSWER: Quick-disconnect coupling
on a low-pressure inflator hose.
What does a pre-dive safety check consist of using the acronym BWRAF? ANSWER:
BCD, Weights, Releases, Air, and Final approval/check.
During the BWRAF pre-dive safety check, what specific check is performed for the 'A'
(Air) step? ANSWER: Confirming the cylinder valve is fully open, monitoring SPG while
taking breaths from both primary and alternate air sources.
Knowledge Assessment Practice 2026 | All
Questions And Answers | Exam Prep
As pressure increases on a gas volume, what happens to the density of the gas and its
volume? ANSWER: The volume decreases and the density increases.
If a flexible air-filled container has a volume of 6 liters at the surface, what will its
volume be at a depth of 20 meters (66 feet) in salt water? ANSWER: 2 liters.
What is the pressure in atmospheres absolute (ata) at a depth of 30 meters (99 feet)
in salt water? ANSWER: 4 ata.
Why must a diver equalizing their air spaces do so gently and frequently during
descent? ANSWER: To prevent barotrauma and discomfort before pressure differences
become significant.
What is the most important rule in scuba diving regarding breathing during descent,
bottom time, and ascent? ANSWER: Breathe continuously and never hold your breath.
What is the primary cause of an air embolism or pulmonary barotrauma during
ascent? ANSWER: Holding breath while ascending, causing expanding air to rupture lung
tissues.
If a diver feels ear discomfort during descent, what is the immediate and correct
action to take? ANSWER: Stop descent, ascend slightly until the pressure/discomfort
relieves, equalize, and then continue descending slowly.
How does salt water differ from fresh water in terms of weight per unit volume and
buoyancy force exerted? ANSWER: Salt water is heavier per unit volume and provides
more buoyant force than fresh water.
A diver neutrally buoyant in fresh water enters salt water with the exact same
equipment configuration. What change in buoyancy will occur? ANSWER: The diver
will become positively buoyant.
What total weight adjustment is necessary if a diver switches from a 3 mm shorty
wetsuit to a 7 mm full wetsuit with hood and gloves? ANSWER: Add weight to
compensate for the additional buoyancy of the thicker neoprene.
,Which piece of equipment provides a secondary air source intended for sharing air
with a buddy in an emergency? ANSWER: Alternate air source / Octopus.
What is the primary function of the first stage of a scuba regulator? ANSWER: To
reduce high pressure from the scuba cylinder to an intermediate pressure above ambient
pressure.
How does a diver maintain proper cylinder buoyancy balance as compressed gas is
consumed throughout a dive? ANSWER: By using a BCD low-pressure inflator to adjust
buoyancy as the cylinder becomes lighter.
When reading a submersible pressure gauge (SPG), when should a diver plan to
begin their ascent to the surface? ANSWER: Before reaching the planned reserve pressure
limit established during pre-dive planning.
What is the purpose of the burst disk integrated into a scuba cylinder valve
assembly? ANSWER: To safely vent excessive pressure if the cylinder is overfilled or exposed
to extreme heat.
What visual indicator or marking on an aluminum scuba cylinder indicates it has
passed an annual inspection? ANSWER: A current visual inspection decal (VIP sticker)
applied by a qualified technician.
How often must a scuba cylinder undergo hydrostatic pressure testing under
standard international regulations? ANSWER: Every 5 years.
What is the result of breathing cold, dry compressed air from a scuba cylinder on a
diver's body temperature and hydration? ANSWER: It causes internal heat loss and
promotes dehydration.
Why should a scuba cylinder never be emptied completely to zero pressure during
storage? ANSWER: To prevent moisture and environmental contaminants from entering the
interior of the cylinder.
What type of valve mechanism remains open if an air supply system is connected and
turned on, but automatically seals if disconnected? ANSWER: Quick-disconnect coupling
on a low-pressure inflator hose.
What does a pre-dive safety check consist of using the acronym BWRAF? ANSWER:
BCD, Weights, Releases, Air, and Final approval/check.
During the BWRAF pre-dive safety check, what specific check is performed for the 'A'
(Air) step? ANSWER: Confirming the cylinder valve is fully open, monitoring SPG while
taking breaths from both primary and alternate air sources.
