PADI Physics and Gas Laws 4

Question 1

A diver's air tank pressure drops from 3000 psi to 750 psi during a dive. The ratio of remaining air to starting air is:

Accepted Answer

1:4

Answer

750 psi remaining out of 3000 psi total = 750/3000 = 1:4 ratio.

Question 2

Gay-Lussac's Law describes the relationship between pressure and temperature at constant:

Accepted Answer

Volume

Answer

Gay-Lussac's Law applies at constant volume, showing pressure is proportional to absolute temperature.

Question 3

At depth, nitrogen narcosis is thought to be caused by:

Accepted Answer

The increased partial pressure of nitrogen affecting nerve membranes

Answer

High partial pressures of nitrogen (and other inert gases) dissolve into nerve cell membranes, impairing neural function.

Question 4

What is the gauge pressure at 66 feet (20 m) of seawater?

Accepted Answer

2 atm (29.4 psi)

Answer

Gauge pressure excludes atmospheric pressure: 66 ft / 33 ft per atm = 2 atm gauge.

Question 5

Water absorbs heat from a diver's body much faster than air because water has a higher:

Accepted Answer

Thermal conductivity

Answer

Water conducts heat about 25 times more efficiently than air, making hypothermia a significant risk for divers.

PADI - Professional Association of Diving Instructors Practice Test