Question

The currently accepted maximum depth limit for safe scuba diving while breathing air is 50 metres. What is the absolute partial pressure of oxygen at this depth?

my solution was as the following, please correct me if I'm wrong:

P=F/A
Thus the pressure exerted by the liquid (water) so that P=weight/area = mg/A = HApg/A =Hpg
where g=9.8ms and p=1030kg

so to workout the presser of oxygen at 50m depth, as the inspired oxygen presser is 0.21*(100-6.3)=19.6KP, which means that 50m *19.6= 980

then P=Hpg = 25750/980=30KPa to 1sf

Answer 1

pressure of water at 50 m;

hpg=50*1030*9.8== 504700 pa
or 504kpa
Now on the water, is atmospheric pressure, so adding that, 605kpa

pressure of O2:
.21*605kpa=127kpa

I can't follow your thinking.