padi IDC dive theory – Physics

Q16
On my self reliant diver course I was asked to breath from my pony bottle at the surface until it was empty. It had 200 bar of pressure and it took me 60 minutes to breath it empty. If I was going to breath from the same bottle filled with 200 bar at 15 meters , how long would the tank last me?
b.) 24 minutes
 
Q17
Underwater object appear _____ and _____, but a phenomenon called visual reversal make them appear ____
a.)   More colourful / further / larger
b.)  Larger / closer / more colourful
c.)   Larger / closer / further
d.)  Smaller / further / larger