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DIVEMASTER FINAL EXAM PREP (2025): 160 QUESTIONS, 100%
CORRECT, VERIFIED, ALREADY GRADED A+, GUARANTEE
PASS 2025-2026
1. At 20 meters / 66 feet in seawater, what is the absolute pressure?
A. 2.0 ATA
B. 2.5 ATA
C. 3.0 ATA
D. 3.5 ATA
Correct answer: C — 3.0 ATA
Rationale (step-by-step):
Surface pressure = 1.0 ATA.
Seawater: every 10 m ≈ +1.0 ATA.
At 20 m: added pressure = 20 ÷ 10 = 2.0 ATA.
Absolute pressure = surface (1.0) + added (2.0) = 3.0 ATA.
Reference: NOAA explanation — pressure increases ~1 atm per 10 m.
pmel.noaa.gov
2. A diver breathes 20 litres of air at the surface. According to Boyle’s
Law, how much volume will this air occupy at 30 m (99 ft)?
A. 5 L
B. 10 L
C. 20 L
D. 40 L
Correct answer: A — 5 L
Rationale (step-by-step):
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Boyle’s Law: P1 V 1=P2 V 2(temperature constant).
Surface: P1=1.0ATA, V 1=20 L.
At 30 m: pressure = 1 + (30 ÷ 10) = 4.0 ATA → P2=4.0.
Solve: V 2=V 1 ×( P1 / P2 )=20 ×(1/ 4 )=5L.
So a gas volume that is 20 L at the surface would be compressed to 5
L at 30 m.
Why it matters: this explains lung compression at depth and lung
expansion on ascent (so you must manage breathing/airway).
References: Boyle’s Law applied to diving (explanation & examples).
Scuba.com+1
3. Which gas law best explains why a diver must never hold their breath
while ascending?
A. Dalton’s Law
B. Boyle’s Law
C. Charles’ Law
D. Henry’s Law
Correct answer: B — Boyle’s Law
Rationale:
Boyle’s Law shows volume of a gas changes inversely with pressure.
As pressure decreases during ascent the volume of trapped gas in the
lungs increases.
If a diver holds their breath while ascending the expanding lung
volume can over-inflate and cause pulmonary barotrauma (air forced
into tissues or blood → arterial gas embolism). Therefore always
breathe normally or exhale while ascending.
Reference: Boyle’s Law and the “don’t hold your breath” diving rule.
Scuba.com+1
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4. The maximum recommended ascent rate in recreational diving
(commonly taught) is:
A. 9 m/min (30 ft/min)
B. 18 m/min (60 ft/min)
C. 30 m/min (100 ft/min)
D. 10 m/min (33 ft/min)
Correct answer: B — 18 m/min (60 ft/min) (note: agencies differ; see
rationale)
Rationale & nuance:
Different agencies and guides give different “recommended”
numbers. Historically 60 ft/min (≈18 m/min) has been widely taught
(PADI commonly cites 60 ft/min). More conservative guidance (and
modern computer defaults / many experienced divers) use 30 ft/min
(≈9 m/min). The practical point: ascend slowly and controlled —
follow your agency/computer and err on the slower side when
unsure.
In exams you’ll usually be expected to name the ascent rate used by
the agency in question (PADI = 60 ft/min; many contemporary
recommendations favor 30 ft/min for added safety).
References: DAN discussion of ascent rates (comparison and why practices
vary) and a common teaching note recommending slower ascent. Divers
Alert Network+1
5. A diver descends to 30 m breathing air. What is the partial pressure
of nitrogen (approx.)?
A. 0.79 ATA
B. 0.79 × 3 ATA = 2.37 ATA
C. 0.79 × 4 ATA = 3.16 ATA
D. 3.2%
Correct answer: C — ≈ 3.16 ATA (partial pressure of N₂ at 30 m)
Rationale (step-by-step):
, 4|Page
Air ≈ 79% nitrogen (fraction 0.79).
At 30 m absolute pressure = 1 + (30 ÷ 10) = 4.0 ATA.
Partial pressure of N₂ = fraction × total pressure = 0.79 × 4.0 = 3.16
ATA.
Reference: Partial pressure concept and example calculations (useful study
reference). Omni Calculator+1
6. Which symptom is most classically associated with carbon monoxide
(CO) poisoning (recognizable sign)?
A. Tingling in fingers
B. Cherry-red lips/skin (classical but uncommon clinically)
C. Joint pain
D. Excessive urination
Correct answer: B — Cherry-red lips/skin (classic sign — but clinically
rare and not sensitive)
Rationale:
CO binds hemoglobin to form carboxyhemoglobin, impairing oxygen
delivery. Historically and in textbooks a “cherry-red” skin/lip
discoloration is described as a classic sign of severe CO poisoning.
Important caveat: Cherry-red coloration is rare and not sensitive —
most symptomatic CO victims present with headache, dizziness,
nausea, confusion, or flu-like symptoms. Don’t rely on the red color
alone for diagnosis.
References: CDC on CO poisoning symptoms and a medical review noting
cherry-red is an infrequent finding. CDC+1
7. Which factor increases a diver’s risk of decompression sickness
(DCS)?
A. Slow ascent rate
B. Proper hydration
DIVEMASTER FINAL EXAM PREP (2025): 160 QUESTIONS, 100%
CORRECT, VERIFIED, ALREADY GRADED A+, GUARANTEE
PASS 2025-2026
1. At 20 meters / 66 feet in seawater, what is the absolute pressure?
A. 2.0 ATA
B. 2.5 ATA
C. 3.0 ATA
D. 3.5 ATA
Correct answer: C — 3.0 ATA
Rationale (step-by-step):
Surface pressure = 1.0 ATA.
Seawater: every 10 m ≈ +1.0 ATA.
At 20 m: added pressure = 20 ÷ 10 = 2.0 ATA.
Absolute pressure = surface (1.0) + added (2.0) = 3.0 ATA.
Reference: NOAA explanation — pressure increases ~1 atm per 10 m.
pmel.noaa.gov
2. A diver breathes 20 litres of air at the surface. According to Boyle’s
Law, how much volume will this air occupy at 30 m (99 ft)?
A. 5 L
B. 10 L
C. 20 L
D. 40 L
Correct answer: A — 5 L
Rationale (step-by-step):
,2|Page
Boyle’s Law: P1 V 1=P2 V 2(temperature constant).
Surface: P1=1.0ATA, V 1=20 L.
At 30 m: pressure = 1 + (30 ÷ 10) = 4.0 ATA → P2=4.0.
Solve: V 2=V 1 ×( P1 / P2 )=20 ×(1/ 4 )=5L.
So a gas volume that is 20 L at the surface would be compressed to 5
L at 30 m.
Why it matters: this explains lung compression at depth and lung
expansion on ascent (so you must manage breathing/airway).
References: Boyle’s Law applied to diving (explanation & examples).
Scuba.com+1
3. Which gas law best explains why a diver must never hold their breath
while ascending?
A. Dalton’s Law
B. Boyle’s Law
C. Charles’ Law
D. Henry’s Law
Correct answer: B — Boyle’s Law
Rationale:
Boyle’s Law shows volume of a gas changes inversely with pressure.
As pressure decreases during ascent the volume of trapped gas in the
lungs increases.
If a diver holds their breath while ascending the expanding lung
volume can over-inflate and cause pulmonary barotrauma (air forced
into tissues or blood → arterial gas embolism). Therefore always
breathe normally or exhale while ascending.
Reference: Boyle’s Law and the “don’t hold your breath” diving rule.
Scuba.com+1
,3|Page
4. The maximum recommended ascent rate in recreational diving
(commonly taught) is:
A. 9 m/min (30 ft/min)
B. 18 m/min (60 ft/min)
C. 30 m/min (100 ft/min)
D. 10 m/min (33 ft/min)
Correct answer: B — 18 m/min (60 ft/min) (note: agencies differ; see
rationale)
Rationale & nuance:
Different agencies and guides give different “recommended”
numbers. Historically 60 ft/min (≈18 m/min) has been widely taught
(PADI commonly cites 60 ft/min). More conservative guidance (and
modern computer defaults / many experienced divers) use 30 ft/min
(≈9 m/min). The practical point: ascend slowly and controlled —
follow your agency/computer and err on the slower side when
unsure.
In exams you’ll usually be expected to name the ascent rate used by
the agency in question (PADI = 60 ft/min; many contemporary
recommendations favor 30 ft/min for added safety).
References: DAN discussion of ascent rates (comparison and why practices
vary) and a common teaching note recommending slower ascent. Divers
Alert Network+1
5. A diver descends to 30 m breathing air. What is the partial pressure
of nitrogen (approx.)?
A. 0.79 ATA
B. 0.79 × 3 ATA = 2.37 ATA
C. 0.79 × 4 ATA = 3.16 ATA
D. 3.2%
Correct answer: C — ≈ 3.16 ATA (partial pressure of N₂ at 30 m)
Rationale (step-by-step):
, 4|Page
Air ≈ 79% nitrogen (fraction 0.79).
At 30 m absolute pressure = 1 + (30 ÷ 10) = 4.0 ATA.
Partial pressure of N₂ = fraction × total pressure = 0.79 × 4.0 = 3.16
ATA.
Reference: Partial pressure concept and example calculations (useful study
reference). Omni Calculator+1
6. Which symptom is most classically associated with carbon monoxide
(CO) poisoning (recognizable sign)?
A. Tingling in fingers
B. Cherry-red lips/skin (classical but uncommon clinically)
C. Joint pain
D. Excessive urination
Correct answer: B — Cherry-red lips/skin (classic sign — but clinically
rare and not sensitive)
Rationale:
CO binds hemoglobin to form carboxyhemoglobin, impairing oxygen
delivery. Historically and in textbooks a “cherry-red” skin/lip
discoloration is described as a classic sign of severe CO poisoning.
Important caveat: Cherry-red coloration is rare and not sensitive —
most symptomatic CO victims present with headache, dizziness,
nausea, confusion, or flu-like symptoms. Don’t rely on the red color
alone for diagnosis.
References: CDC on CO poisoning symptoms and a medical review noting
cherry-red is an infrequent finding. CDC+1
7. Which factor increases a diver’s risk of decompression sickness
(DCS)?
A. Slow ascent rate
B. Proper hydration
