PADI Enriched Air Nitrox Diving 4

Question 1

What is the maximum oxygen fraction (FO₂) that PADI Enriched Air certification covers?

Accepted Answer

40%

Answer

The PADI Enriched Air Diver course covers mixes up to 40% oxygen (EANx40); higher percentages require additional technical training.

Question 2

A diver notices symptoms of CNS oxygen toxicity — visual disturbances and lip twitching — while at depth. What is the immediate priority?

Accepted Answer

End the dive by performing a controlled ascent with the buddy

Answer

If CNS toxicity symptoms appear, the diver must immediately end the dive with a controlled ascent; convulsions underwater can be fatal.

Question 3

Why is a personal oxygen analyzer recommended rather than relying on the fill station's documentation?

Accepted Answer

Mixes can stratify or be mislabeled, and diver verification is a personal safety responsibility

Answer

Gas mixes can be incorrectly blended or labeled; the diver is ultimately responsible for verifying the mix before entering the water.

Question 4

How does a nitrox dive computer differ from a standard air computer in its core algorithm?

Accepted Answer

It allows the diver to input the oxygen fraction to calculate nitrogen exposure correctly

Answer

A nitrox computer lets the diver enter the actual FO₂ so the algorithm correctly models nitrogen off-gassing for the specific mix rather than assuming 21% oxygen.

Question 5

Which scenario represents the highest risk of oxygen toxicity for an enriched air diver?

Accepted Answer

Using EANx36 at 100 feet for 20 minutes

Answer

EANx36 at 100 feet produces a pO₂ of approximately 1.44 ata, the highest partial pressure among the options and closest to toxic levels.

(PADI) Certified Professional Association of Diving Instructors Diver Practice Test

(PADI) Certified Professional Association of Diving Instructors Diver Practice Test

PADI Enriched Air Nitrox Diving 4