55 PADI final exam practise questions and answers

Last Updated on April 16, 2021 by Dan

55 PADI final exam practise questions

The PADI Open Water Diver final exam consists of 50 questions. We have included these practise questions and answers to help you study. Most of the PADI Open Water Diver final exam questions are multiple-choice questions, along with a couple of ‘place the answers in the correct order’ questions. You don’t have a time limit to complete the exam.

However, as a PADI Open Water Diver student, you will need to pass the Open Water Diver exam with a score of 75% or greater. That means you can get 12 questions wrong. If you fail the Open Water Diver exam, you can retake the exam.



55 Practise Q & A

Here are some practise questions and answers to help you along:

  • If an object is neutrally buoyant (does not sink or float) in fresh water, the same object placed into salt water would

A sink.
B either sink or float.
C do nothing.
D float.

D float.

Salt water is heavier than fresh water because it has dissolved minerals in it. This means it causes more upward force (buoyancy) on an object. An object that is neutrally buoyant in fresh water would float in salt water because there is greater upward force.

See Being a Diver I – Buoyancy and Controlling Buoyancy.

2) I blow up a balloon, tie it off, and take it to the bottom of the swimming pool. What will happen to the balloon and the air inside it?

A The balloon will get bigger and the air inside the balloon will be less dense (molecules move further apart).
B The balloon will get smaller and the air inside the balloon will be more dense (molecules move closer together).
C The balloon will get bigger and the air inside the balloon will be more dense.
D The balloon will get smaller and the air inside the balloon will be less dense.

B The balloon will get smaller and the air inside the balloon will be more dense (molecules move closer together).

As water pressure increases, the volume of an air space will decrease. This causes the density of the air inside to increase and air molecules are pushed closer together. The balloon would get smaller and the air density inside would be greater.

See Being a Diver I – Water Pressure and Air Volume Effects.

3) I turn a glass upside down, trap the air in it by putting it in water, and then I take the glass down to 10 meters. The air space would

A become half the size it was at the surface.
B not change in size.
C become 1/3 the size it was at the surface.
D become 2/3 the size it was at the surface.

A become half the size it was at the surface.

At 10 meters, the pressure is 2 bar. An air volume taken to this depth from the surface would decrease and become half the size.

See Being a Diver I – Water Pressure and Air Volume Effects.

4) If I am not able to equalize (clear) my body air spaces, it may be because I have

A seasickness.
B heart disease and high blood pressure.
C a cold, allergy or another medical problem.
D anxiety.

C A cold, allergy or another medical problem.

A cold, or any congestion, can block air passages in your ears and sinuses, making equalization difficult or impossible.

See Being a Diver I – The Effects of Increasing Pressure on Body Air Spaces.

5) If my ears or sinuses hurt while I am descending (going down), it usually means

A my air spaces are equalized.
B my mask strap is too tight.
C I am feeling a squeeze and need to equalize.
D my mask is too small.

C I am feeling a squeeze and need to equalize.

Pain in your ears or sinuses means that they aren’t equalized. Stop your descent and ascend slightly to relieve pressure on your ears. Then attempt to equalize again. If you can’t equalize, end the dive.

See Being a Diver I – The Effects of Increasing Pressure on Body Air Spaces.

6) The best place for me to position an alternate air source is

A loose by my side so I can find it fast.
B in the triangle area formed by my chin and the lower corners of my rib cage.
C to the base of my cylinder.
D to the back of my BCD between my shoulder blades and waist.

B In the triangle area formed by my chin and the lower corners of my rib cage.

Your alternate air source attaches with a quick release in the triangle area formed by your chin and the lower corners of your rib cage. Avoid letting your alternate air source dangle unsecured from your kit.

See Equipment I – Regulators.

 7) Lung overexpansion injuries can be caused by

A scuba diving without a buddy.
B continuing a dive when not properly weighted.
C not drinking enough water before scuba diving.
D holding my breath while scuba diving.

D Holding my breath while scuba diving.

Blocking off your lungs by holding your breath and ascending could cause them to overexpand and rupture, which is a serious injury that could result in paralysis and death. Breathing continuously while scuba diving keeps air passages open allowing expanding air to escape.

See Being a Diver I – The Effects of Decreasing Pressure on Body Air Spaces.

8) If my cylinder of air lasts 60 minutes while I am at the surface breathing normally, assuming all else is the same, how long will it last at 20 meters breathing normally?

A 60 minutes
B 20 minutes
C 15 minutes
D 12 minutes

B 20 minutes

60/3=20

For each 10 meters we go down, we have one more atmosphere of pressure. Also, remember to add in the 1 atmosphere of pressure at the surface.

So, going down to 20 meters, we will have 2 atm + 1 atm = 3 atm of pressure.

9) How often should I take my scuba cylinder to be visually inspected by my dive center?

A Once a year.
B Once every two years.
C Every six months.
D Every five years.

A Once a year.

Have your cylinder visually inspected annually for internal corrosion or other contamination/damage.

See Equipment I – Cylinders.

10) The difference between DIN valves and yoke valves is that DIN valves

A are made from durable plastic.
B contain a spring-operated shutoff valve that is held open by cylinder pressure.
C have an o-ring in them.
D have threaded openings to screw the regulator into.

D Have threaded openings to screw the regulator into.

With the DIN system, the regulator screws into the valve. The yoke system holds the regulator first stage to the cylinder with a clamp system.

See Equipment I – Cylinders.

11) Which of the following is part of proper care for my scuba cylinder?

A Sand and repaint it every year.
B Dry it in the sun.
C Keep some air in it.
D Have it pressure tested every month.

C Keep some air in it.

You should keep some air in the cylinder to prevent moisture from entering and causing corrosion. Also, have it pressure tested at required intervals, usually two to five years. Have it visually inspected annually. Store it standing in a safe place and keep it away from high heat.

See Equipment I – Cylinder Care.

12) Refer to the regulator picture. Each regulator part has a number next to it. Please choose the correct number for the choices below.

regulator first stage,
regulator second stage
alternate air source second stage
low pressure inflator hose for the BCD
instrument console/gauges/computer

  1. regulator first stage, 2. regulator second stage, 3. alternate air source second stage, 4. instrument console/gauges/computer.5. low pressure inflator hose for the BCD.

    Your regulator consists of five components. The first stage is the “hub” of your regulator and supplies air to the components – the second stage, alternate air source, low pressure inflator hose and SPG/dive computer.

    See Equipment I – Regulators.

13) When I look at things underwater they often seem ___________ than they look on the surface.

A larger and/or nearer
B larger and/or further away
C smaller and/or further away
D smaller and/or nearer

A Larger and/or nearer

As light travels through water and into your mask, it bends, or refracts. This makes objects appear larger and closer than they really are.

See Being a Diver II – Seeing and Hearing as a Diver.

14) ___________ travels faster in water than it does in air. This is why you cannot easily tell where it comes from.

A Light
B Current
C Aquatic life
D Sound

D Sound

Sound travels about four times faster in water than in air. This makes it difficult to determine where the sound is coming from because it seems to come from all around or directly overhead.

See Being a Diver II – Hearing Underwater.

15) Unless there are laws that say differently, I should stay within ___________ of my dive flag.

A 60 meters
B 30 meters
C 15 meters
D 5 meters

C 15 meters

If there are no specific local laws regarding dive flags, stay within 15 meters of the flag. Boats should stay 30 to 60 meters away.

See Equipment III – Dive Flags.

B stop all activity and rest, holding onto something for support if possible.

If you find it difficult to breathe you’re overexerted. Immediately stop and rest while holding onto something for support to restore normal breathing. Continue only after you’ve regained a normal, slow breathing rate. See Being a Diver II – Overexertion.

A compress (feel thinner) from water pressure, and I will lose buoyancy and warmth.

The small bubbles in your wet suit compress as you get deeper. This causes your buoyancy to decrease and makes the wet suit thinner, which affects warmth. To control your buoyancy, add small amounts of air to your BCD frequently during descent. See Being a Diver II – Descents in Open Water.

C float at eye level while holding a normal breath of air and with an empty BCD.

Part of having good buoyancy and trim is having the right amount of weight. You should float at eye level with an empty BCD and holding a normal breath. When you exhale, you should slowly sink. See Your Skills as a Diver II – Weight Check and Proper Weighting.

A Stop, hold it, stay there.

This is the hand signal for stop, hold it or stay there. See Your Skills as a Diver I – Hand Signals.