SDI Certification Exam Review Newest 2025
Complete Exam/ Actual Questions with Correct
Verified Answers/ Rated A+
What should you do if a potentially dangerous animal underwater does not
leave your area? - Correct Answer - Remain still
Remain calm
Slowly leave area
List three different reasons that it is advisable to check with your local dive
center before diving in an unfamiliar area. - Correct Answer - 1) Rip
currents could be prevalent
2) Thermoclines could affect thermal protection
3) YOU ARE SUBJECT TO LOCALITY (be aware of laws and regulations
What is the absolute pressure in atm at 20m/66ft? - Correct Answer - 3 atm
absolute
What will be the volume in a ball that is filled with 2 cubic feet of air at 30
m/99ft when it is taken to the surface? - Correct Answer - 8 cubic feet
How many times more dense is air in a balloon at 4 atm compared to the
air density at the surface? - Correct Answer - 4 times
pg. 1
, If a scuba cylinder lasts two hours at sea level, how long will it last at 20
m/66 ft? - Correct Answer - 40 min
How often should you equalize during descent? - Correct Answer - Early
and often; at the surface and then every couple feet so no discomfort is felt
What should you do if you experience discomfort in your ears upon
descending? - Correct Answer - Immediately stop descending and ascend
a few feet until you are shallow enough not to feel any discomfort
What is reverse block? - Correct Answer - Occurs when air cannot expand
or escape freely when ascending
What should you do if you experience a reverse block upon ascending? -
Correct Answer - Descend a couple feet and stay there until air has time to
vent
What is the most important rule in scuba diving? - Correct Answer - Do not
hold your breath, breathe continuously
What is the most serious injury that a diver could suffer from if they hold
their breathe upon ascending? - Correct Answer - Lung overexpansion
injuries
Which gas component in air causes decompression sickness and
narcosis? - Correct Answer - Nitrogen
What medical can occur if a diver ascends much too rapidly for nitrogen to
be slowly released? - Correct Answer - Decompression sickness
pg. 2
Complete Exam/ Actual Questions with Correct
Verified Answers/ Rated A+
What should you do if a potentially dangerous animal underwater does not
leave your area? - Correct Answer - Remain still
Remain calm
Slowly leave area
List three different reasons that it is advisable to check with your local dive
center before diving in an unfamiliar area. - Correct Answer - 1) Rip
currents could be prevalent
2) Thermoclines could affect thermal protection
3) YOU ARE SUBJECT TO LOCALITY (be aware of laws and regulations
What is the absolute pressure in atm at 20m/66ft? - Correct Answer - 3 atm
absolute
What will be the volume in a ball that is filled with 2 cubic feet of air at 30
m/99ft when it is taken to the surface? - Correct Answer - 8 cubic feet
How many times more dense is air in a balloon at 4 atm compared to the
air density at the surface? - Correct Answer - 4 times
pg. 1
, If a scuba cylinder lasts two hours at sea level, how long will it last at 20
m/66 ft? - Correct Answer - 40 min
How often should you equalize during descent? - Correct Answer - Early
and often; at the surface and then every couple feet so no discomfort is felt
What should you do if you experience discomfort in your ears upon
descending? - Correct Answer - Immediately stop descending and ascend
a few feet until you are shallow enough not to feel any discomfort
What is reverse block? - Correct Answer - Occurs when air cannot expand
or escape freely when ascending
What should you do if you experience a reverse block upon ascending? -
Correct Answer - Descend a couple feet and stay there until air has time to
vent
What is the most important rule in scuba diving? - Correct Answer - Do not
hold your breath, breathe continuously
What is the most serious injury that a diver could suffer from if they hold
their breathe upon ascending? - Correct Answer - Lung overexpansion
injuries
Which gas component in air causes decompression sickness and
narcosis? - Correct Answer - Nitrogen
What medical can occur if a diver ascends much too rapidly for nitrogen to
be slowly released? - Correct Answer - Decompression sickness
pg. 2
