# PADI IDC Revision - Physics

### Test yourself with these questions

PADI IDC Revision – Physics Here are some typical PADI IDC physics questions (and answers) for you to try. Videos to help if you get stuck!

Take your time – good luck!

## PADI IDC Revision - Physics - Pressures Underwater

Test yourself with these questions. If you get stuck, all is explained in the video below from the PADI IDC Theory Preparation Course

### PADI IDC Exam Questions

###### What is the gauge pressure at 34 metres / 112 feet of fresh water?

###### 3.3 atm / 48.4 psi

###### Is the gauge pressure for a given depth in salt water be the same/greater/less than the same depth of fresh water?

###### Greater than

###### What is the absolute pressure at 20 metres / 66 feet of fresh water?

###### 3 bar / ata

###### What is the absolute pressure at 34 metres / 112 feet of fresh water?

###### 4.4 ata / 64.5 psia

How did you get on? Check out this video for lots more information

### PADI IDC Revision - Physics - Calculate pressures in water

## PADI IDC Revision - Physics - Effects of Pressure

OK, now try these questions. These ones are so important.

Usually Physics exams have over more questions about the effects of pressure than any other subject.

Again, if you get stuck, there’s a great video from the Online PADI IDC Theory preparation course

Click the PADI IDC Guide button to find out more information about how our online PADI IDC Preparation Courses can help you.

### PADI IDC Exam Questions

Imagine that the air in your cylinder was accidentally mixed with 0.5% carbon monoxide. If you took this to 20 metres / 66 feet, what would the surface equivalent percentage be?

###### 1.5%

The actual percentage would still be 0.5%

But the effect would be equivalent to surface percentage of 1.5%

###### Approximately how much air must be pumped down from the surface to fill a 40 litre/1.4 cubic feet container if the container lies in 20 metres/66 feet of sea water?

###### 120 litres / 4.2 cubic feet

###### Approximately how much air must be pumped down from the surface to fill a 50 litre container if the container lies in 40 metres/132 feet of sea water?

###### 250 litres

###### If it takes a diver 90 minutes to breathe all of the air from a cylinder at the surface, appoximately how long will the air in that cylinder last at 20 metres / 66 feet of sea water if all of the other conditions remain the same?

30 minutes

###### A diver is using a cylinder filled with air (21% Oxygen, 79% Nitrogen) With respect to the oxygen, at approximately what depth would breathing this mix have the same effect as breathing pure oxygen at the surface?

40 metres/130 feet

###### During a wall dive in the ocean, you release a balloon at a depth of 24 metres/80 feet. The balloon contains one litre of air. What is the balloon’s volume at the surface?

###### 3.4 litres

How did you get on?

There’s a lot more information about the effects of pressure questions in this video here

Including the wonderful “BOX METHOD” for working out the answers

### PADI IDC Revision - Physics - Effects of Pressure

**These questions and videos are from our online Preparation Course. Please don’t over complicate Physics. It’s easier than you think. More information here: PADI IDC Theory Preparation Course Or sign up for an online course here, where you and I can work together to improve your knowledge **

## PADI IDC Revision - Physics -displacement

Now we move onto the displacement questions. Make sure that you read the question!

Check if it’s in salt or fresh water!

### PADI IDC Exam Questions

Your dive boat bumps into a large box floating just under the surface of a freshwater lake. After bringing it aboard, you determine the weight to be 75 kilograms/165 pounds. How much water does it displace?

75 litres / 2.64 cubic feet

###### A 200 kilogram / 440 pound anchor that displaces 127 litres / 4.5 cubic feet of water lies on the sea floor in 17 metres/56 feet. What is the minimum amount of water that must be displaced from a lifting device to bring the anchor to the surface?

###### 67 litres / 2.38 cubic feet

If a diver weighing 75 kilograms / 165 pounds in neutrally buoyant in fresh water, the same diver with the same equipment would _____ in salt water.

###### Float

What is the minimum amount of water that must be displaced from a lifting device to bring a 453.5 kilogram / 1000 pound anchor to the surface from 40 metres/ 132 feet of salt water in the anchor displaces 254.8 litres/nine cubic feet?

###### 185.5 litres/6.6 cubic feet

### How did you get on?

Don’t worry if you got a bit confused with these questions. There’s a lot more information explained simply in this video from the Online PADI IDC Theory Preparation Course.

### Questions on other subjects

## Much more to revise on Physics

Of course, PADI IDC Exams have questions about so many more subjects than Pressure or Displacement.

Join our Online Course. I’ll work with you to cover every subject that you’re likely to come across during your courses.

I’ll show you ways to gain knowledge, pass exams and even teach the topics to other people.

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**These questions and videos are from our online Preparation Course. Please don’t over complicate Physics. It’s easier than you think. More information here: PADI IDC Theory Preparation Course Or sign up for an online course here, where you and I can work together to improve your knowledge **

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