PADI Diving Theory & Safety 4

Question 1

What is the purpose of an alternate air source (octopus) in recreational diving?

Accepted Answer

To supply air to a buddy who has run out of breathing gas

Answer

To provide a backup regulator if the primary fails mechanically

Answer

To inflate the BCD orally if the low-pressure inflator fails

Answer

To sample air quality from different parts of the tank

Question 2

When equalizing ear pressure during descent, a diver should:

Accepted Answer

Equalize early and often before discomfort occurs

Answer

Wait until feeling discomfort, then equalize forcefully

Answer

Only equalize at the bottom of the descent

Answer

Pinch the nose and blow as hard as possible

Question 3

A diver at 20 meters depth on air is breathing at what absolute pressure?

Accepted Answer

3 ATA

Answer

1 ATA

Answer

2 ATA

Answer

4 ATA

Question 4

What does a BCD (Buoyancy Control Device) primarily help a diver achieve?

Accepted Answer

Neutral buoyancy at depth and positive buoyancy at surface

Answer

Thermal protection in cold water

Answer

Protection against aquatic life

Answer

Air supply management during a dive

Question 5

If a diver surfaces with a headache, fatigue, and cherry-red skin coloration after filling tanks from a vehicle exhaust source, the cause is likely:

Accepted Answer

Carbon monoxide poisoning

Answer

Decompression sickness

Answer

Nitrogen narcosis

Answer

Hyperoxia

Question 6

What is the significance of the 'surface interval' between dives?

Accepted Answer

It allows residual nitrogen to off-gas and reduces DCS risk on subsequent dives

Answer

It allows the diver to eat and rehydrate

Answer

It allows the BCD to dry properly

Answer

It is required by law in the United States

Question 7

Which of the following is a contraindication to scuba diving?

Accepted Answer

Spontaneous pneumothorax history

Answer

Being over the age of 40

Answer

Mild myopia requiring corrective lenses

Answer

A history of mild seasickness