This question can be answered using only Table 3 from your PADI RDP Table. 

Intersect C along the top with C on the left-hand side and you'll find 2 boxes containing differing numbers.

The key below the table shows what each of these means. The blue box is the maximum allowed bottom time for a repetitive dive to this depth. The white is the Residual Nitrogen Time or RNT.

Carbon Monoxide forms a reversible bond with Haemoglobin much the same way Oxygen does. Unfortunately, it bonds 200 times more tightly then Oxygen forming Carboxyhaemoglobin.

Carboxyhaemoglobin has a half-life of several hours and impedes the transportation of Oxygen from the lungs to the rest of the body which is why ciggerette smoking prior to dives should be avoided. 

The PADIEmergancy Oxygen Provider Course may be taught to anyone of any age, with an interest. As a non-diving program, there is no diving prerequisite, much like the EFR programs, and may be used in non-diving situations.

As with the EFR programs, consideration should be taken when admitting children on the course.

Want to become a PADI Emergency Oxygen Provider Specialty Instructor? Book Now and Ignite YourLife today!

Questions like this can catch you out if you've been focusing on the partial pressure of the gas; converting the physical amount into its physiological effect when breathed by a diver at pressure.

The question is asking what the physical amount is in the cylinder. This will not change with the change in pressure.1% in the cylinder at the surface will still be 1% in the cylinder at 30m/sw.

Want to learn more about physics in diving? Join one of my upcoming PADI Professional Development Programs - the PADI Divemaster or the PADI Instructor Course.

Visible light is electromagnetic energy and depending on how far the light has to travel through a liquid will determine what parts of the wavelength we can see. 

This means the deeper or murkyer the water we're diving in will determine what colours we can see.