PADI Divemaster Certification Practice Exam

A diver using EANx32 at 10 metres needs to calculate oxygen exposure based on what partial pressure?

1. 0.32 bar

2. 0.64 bar

3. 1.0 bar

4. 1.4 bar

The correct answer is: 0.64 bar

To calculate the partial pressure of oxygen when using EANx32 (which is a mixture of 32% oxygen), you first need to determine the total pressure at the given depth of 10 meters. Water adds pressure, so at 10 meters depth, the total pressure is approximately 2.0 bar (1 bar for surface pressure plus an additional 1 bar for the water column). Next, to find the partial pressure of oxygen in the EANx32 mixture, you multiply the total pressure by the fraction of oxygen in the mixture. EANx32 has 0.32 (or 32%) oxygen, therefore the calculation is as follows: Partial Pressure of Oxygen = Total Pressure x Fraction of Oxygen Partial Pressure of Oxygen = 2.0 bar x 0.32 Partial Pressure of Oxygen = 0.64 bar Thus, the correct answer is 0.64 bar, representing the partial pressure of oxygen that the diver is exposed to while breathing EANx32 at a depth of 10 meters. This information is critical for monitoring potential oxygen toxicity and ensuring safe diving practices.