Question 1 of 12

A passing yacht has snarled its anchor and had to cut it free. The owner has asked you to recover it. The anchor weighs 200kg and has a volume of 8 ltrs. It is lying in 30m of seawater. How much water will you need to displace to make it neutral, and then surface it?

186.17
191.76
192
186.63

Calculation:
If an object lies at the bottom of the SEA.
Take its weight and divide by one point zero THREE.
Then subtract its volume.
200/1.03=194.17
194.17-8=186.17

Question 2 of 12

Approximately how much air would have to be pumped from the surface to fill a 200 Litre container if the container is at 23m in Salt Water?

647
4600
460
660

Calculation:
Step 1: 23/10+1=3.3
Step 2: 200×3.3=660

Question 3 of 12

If a glass of water is placed in a hyperbaric chamber and the pressure in the chamber is increased to 30m/4 ata what will happen to the gas dissolved in the water?

The amount of gas dissolved in the water will decrease
The amount of gas dissolved in the water will decrease and bubbles will form
The amount of gas dissolved in the water will increase
The amount of gas dissolved in the water will remain the same

Explanation: When you increase the pressure surrounding a liquid the gas dissolved will increase. If you decrease the pressure the gas dissolved will decrease. So in this question it is an increase in pressure, resulting in an increase in dissolved gas.

Question 4 of 12

When breathing a tank of Nitrox 32 in fresh water, at a depth of 10m. The partial pressure of Oxygen will be______. The partial pressure of Nitrogen will be_____.

0.32/0.68
1.36/0.64
0.63/1.34
0.64/1.36

Calculation:
Ambient pressure at 10m fresh water is 1.971 ata
0.32×1.971=0.63 (Oxygen)
0.68×1.971=1.34 (Nitrogen)

Question 5 of 12

A scuba tank has been contaminated with Carbon Monoxide. It contains 1.5% Carbon Monoxide. What will the surface equivalent percentage of Carbon Monoxide be at 30m?

1.5%
2%
5%
6%

Explanation: Surface equivalent percentage is the same as the partial pressure. If you are asked what the surface equivalent percentage would be, answer it as though it asked what the partial pressure would be. So Depth is 30m which is 4ata. 4×1.5=6%

Question 6 of 12

If you take a tank with 180bar of pressure in it and move it from a room which is 10°C to a hot sun at 35°C what will the new pressure in tank become over time?

215
209
195
167

Calculation:
Temperature change: 35-10 = 25°C
Pressure change: 25×0.6 = 15 bar
New pressure: 180+15 = 195 bar

Question 7 of 12

A scuba tank has been contaminated with Carbon Monoxide. It contains 2.5% Carbon Monoxide. Breathing from this tank at 28m SALT water would have the same effect as breathing what percentage at the surface?

1.5
9.5
7.5
2.5

Calculation:
28/10+1=3.8 ata
2.5%×3.8=9.5% equivalent at surface

Question 8 of 12

If an Oxygen partial pressure of 1.6 is the point at which there is an unacceptable risk of CNS Oxygen toxicity, at what depth of seawater in meters would a tank of pure oxygen become potentially toxic?

6
8
5
4

Calculation:
1.6/1.0 = 1.60 ata
(1.60-1)×10 = 6 meters

Question 9 of 12

If it takes you 24 minutes to breathe through a tank of air at 39m, how long will it take to breathe the same tank at 16m, if all other variables remain the same? Answer to the nearest minute. The diver is in Salt Water.

59
36
74
45

Calculation:
Step 1: 39/10+1=4.9 ata
Step 2: 24×4.9=117.6 mins
Step 3: 16/10+1=2.6 ata
Step 4: 117.6/2.6=45 mins

Question 10 of 12

The reduced atmospheric pressure when diving at altitude:

Causes a change in tank pressure as you ascend from sea level to altitude
Results in a reduced pressure gradient when ascending from depth to the surface, as compared to diving at sea level
The pressure gradient would be the same at altitude as it would be at sea level
Results in an increased pressure gradient when ascending from depth to the surface, as compared to diving at sea level

Explanation: The ambient pressure at the surface when at altitude is LESS than it is at sea level. This means the PROPORTIONAL pressure difference when you surface from a dive at altitude is greater than when at sea level. This is often referred to as a greater/increased pressure GRADIENT in PADI exams.

Question 11 of 12

An object weighing 65kg with a volume of 40 Litres, is lying in Freshwater. How much air must you add to a lifting device to bring it to the surface.

25
23.1
15
26.95

Explanation: In fresh water questions about lifting objects are easy. You just subtract the volume of the object (displacement) from the weight. 65-40=25

Question 12 of 12

Visual reversal is caused by?

Turbidity
Refraction
Absorption
Gas Narcosis

Explanation: Turbidity is poor visibility. Lots of particles in the water. The light bounces off these particles causing Visual Reversal, which is objects seeming more distant or further away.

Physics Quiz