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ADCI Surface Supplied Mixed Gas Diver
Certification Practice Exam Questions And
Correct Answers (Verified Answers) Plus
Rationales 2026 Q&A | Instant Download
Pdf.
Q1. According to Boyle's Law, if a diver descends from the
surface to 66 feet in seawater (3 ATA), what happens to the
volume of a flexible air-filled space?
A) Volume remains the same
B) Volume doubles
C) Volume reduces to 1/3 of original
D) Volume reduces to 1/2 of original
Correct Answer: C
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Rationale: Boyle's Law: P1V1 = P2V2. At 66 fsw, absolute
pressure = 3 ATA (surface 1 ATA + 66/33 = 2 ATA gauge = 3
ATA absolute). V2 = V1 × (P1/P2) = 1 × (1/3) = 1/3 original
volume.
Q2. A diver at 132 fsw (5 ATA) is breathing a gas mixture.
The partial pressure of oxygen (PPO2) should not exceed
what maximum for working dives according to ADCI
standards?
A) 1.0 ATA
B) 1.4 ATA
C) 1.6 ATA
D) 2.0 ATA
Correct Answer: B (1.4 ATA for working; 1.6 ATA for resting)
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Rationale: ADCI standards limit PPO2 to 1.4 ATA during working
phases and 1.6 ATA during resting or decompression to reduce
risk of CNS oxygen toxicity.
Q3. A diver at 165 fsw is breathing a mixture with 10%
oxygen. What is the PPO2?
A) 0.5 ATA
B) 0.6 ATA
C) 0.7 ATA
D) 1.0 ATA
Correct Answer: B
Rationale: Pressure at 165 fsw = 165/33 + 1 = 5 + 1 = 6
ATA. PPO2 = 0.10 × 6 = 0.6 ATA.
Q4. What is the maximum PO2 generally permitted for the
oxygen partial pressure during the decompression phase of a
mixed gas dive?
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A) 1.0 ATA
B) 1.4 ATA
C) 1.6 ATA
D) 2.0 ATA
Correct Answer: C (1.6 ATA)
Rationale: During decompression (resting phases), ADCI allows
PPO2 up to 1.6 ATA to accelerate inert gas elimination while
managing oxygen toxicity risk.
Q5. Gauge pressure at 99 fsw is approximately:
A) 2 ATA
B) 3 ATA
C) 4 ATA
D) 5 ATA
Correct Answer: B (3 ATA gauge)
ADCI Surface Supplied Mixed Gas Diver
Certification Practice Exam Questions And
Correct Answers (Verified Answers) Plus
Rationales 2026 Q&A | Instant Download
Pdf.
Q1. According to Boyle's Law, if a diver descends from the
surface to 66 feet in seawater (3 ATA), what happens to the
volume of a flexible air-filled space?
A) Volume remains the same
B) Volume doubles
C) Volume reduces to 1/3 of original
D) Volume reduces to 1/2 of original
Correct Answer: C
,Page 2 of 45
Rationale: Boyle's Law: P1V1 = P2V2. At 66 fsw, absolute
pressure = 3 ATA (surface 1 ATA + 66/33 = 2 ATA gauge = 3
ATA absolute). V2 = V1 × (P1/P2) = 1 × (1/3) = 1/3 original
volume.
Q2. A diver at 132 fsw (5 ATA) is breathing a gas mixture.
The partial pressure of oxygen (PPO2) should not exceed
what maximum for working dives according to ADCI
standards?
A) 1.0 ATA
B) 1.4 ATA
C) 1.6 ATA
D) 2.0 ATA
Correct Answer: B (1.4 ATA for working; 1.6 ATA for resting)
,Page 3 of 45
Rationale: ADCI standards limit PPO2 to 1.4 ATA during working
phases and 1.6 ATA during resting or decompression to reduce
risk of CNS oxygen toxicity.
Q3. A diver at 165 fsw is breathing a mixture with 10%
oxygen. What is the PPO2?
A) 0.5 ATA
B) 0.6 ATA
C) 0.7 ATA
D) 1.0 ATA
Correct Answer: B
Rationale: Pressure at 165 fsw = 165/33 + 1 = 5 + 1 = 6
ATA. PPO2 = 0.10 × 6 = 0.6 ATA.
Q4. What is the maximum PO2 generally permitted for the
oxygen partial pressure during the decompression phase of a
mixed gas dive?
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A) 1.0 ATA
B) 1.4 ATA
C) 1.6 ATA
D) 2.0 ATA
Correct Answer: C (1.6 ATA)
Rationale: During decompression (resting phases), ADCI allows
PPO2 up to 1.6 ATA to accelerate inert gas elimination while
managing oxygen toxicity risk.
Q5. Gauge pressure at 99 fsw is approximately:
A) 2 ATA
B) 3 ATA
C) 4 ATA
D) 5 ATA
Correct Answer: B (3 ATA gauge)
