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Dive Theory Mock Exam A

Dive Theory Mock Exam A

PADI Instructor Development

Constants used for Dive Theory Exams


1 litre of salt water weighs 1.03 kilograms

1 litre of fresh water weighs 1 kilogram

Pressure increases by 1 ATM every 10 metres of salt water

Pressure increases by 1 ATM every 10.3 metres of fresh water

Pressure changes per unit of salt water = 0.100 ATM/m

Pressure changes per unit of fresh water = 0.097 ATM/m



1) What is the absolute pressure at 24m in sea water?
a) 2.4 atm
b) 22.75 atm
c) 2.28 atm
d) 3.4 atm

2) What is the gauge pressure at 16m in sea water?
a) 1.6 atm
b) 2.55 atm
c) 1.55 atm
d) 2.6 atm

3) What is the gauge pressure at 16m in fresh water?
a) 1.6 atm
b) 2.55 atm
c) 1.55 atm
d) 2.6 atm

4) If a sealed, flexible air filled container with a volume of 17 litres at 19m of sea water is taken to 37m, what would the new volume be?
a) 21.56 litres
b) 10.48 litres
c) 3.7 litres
d) 26.5 litres

5) If an object weighs 197 kg and displaces 16 litres, how much water needs to be displaced to achieve neutral buoyancy in 18m of fresh water?
a) 179.56 litres
b) 181 litres
c) 265 litres
d) 289 litres

6) The colour red disappears as depth increases underwater due to?
a) absorption
b) refraction
c) reflection
d) diffusion

7) If a sealed, inflexible, air filled container with a volume of 3 litres is taken to a depth of 30m, the volume will ?
a) increase
b) decrease
c) remain unchanged
d) the answer cannot be determined

8) A scuba tank containing 1% of carbon monoxide at the surface is taken to 30m, if a diver were to breathe from the tank at this depth, it would have the same effect as breathing __ % of carbon monoxide at the surface?
a) 1%
b) 2%
c) 3%
d) 4%

9) If an air filled balloon is taken from the surface to 40m, what will happen to the volume of the balloon?
a) the volume decreases to 1/5 th
b) the volume halves
c) the volume increases by 1/5th
d) the volume remains unchanged

10) If a balloon and a scuba tank are both filled with air at room temperature and then placed outside in near freezing conditions, what will happen to each?
a) the volume of the balloon and tank will both increase
b) the volume of the balloon will decrease and the pressure in the tank will decrease
c) the volume of the balloon will increase and the pressure in the tank will increase
d) the volume of the balloon and tank will both decrease

11) If the ambient pressure surrounding an open liquid filled container that is saturated with nitrogen is rapidly decreased, what will happen to the gas?
a) the gas comes out of solution & bubbles may form
b) remains unchanged
c) the gas dissolves into the solution
d) the gas becomes toxic

12) Approximately how much air must be pumped down from the surface to fill a 40 litre container if the container lies in 40m of salt water?
a) 40 litres
b) 80 litres
c) 160 litres
d) 200 litres


1) Gas exchange between the tissues and the blood occurs:
a) in the heart
b) in the arteries
c) in the veins
d) in the capillaries

2) To avoid problems with dead air space:
a) dive well within dive table limits
b) breathe slowly with deep, normal breaths
c) avoid wearing a restrictive dry suit
d) equalize air spaces early and often

3) Carotid-sinus reflex is:
a) slowing of the heart
b) automatic bleeding of the sinuses
c) irregular heart beat
d) reduction of the sinus dead air space

4) Carotid-sinus reflex is caused by:
a) constriction of the carotid arteries
b) the inability to equalize
c) hyperventilation
d) hypocapnia

5) When Skin Diving, the correct breathing technique before leaving the surface is:
a) Rapid Breathing
b) Hyperventilation
c) Skip breathing
d) Relaxed diaphragm breathing

6) Decompression illness is:
a) a blanket term for DCS & lung over expansion injuries
b) the preferred term for arterial gas embolism
c) a term that describes any pressure-related condition
d) a term interchangeable with “decompression sickness”

7) Heat stroke signs and symptoms include:
a) strong rapid pulse, no perspiration, skin hot to touch
b) weak rapid breathing, weak rapid pulse, skin cool and clammy, profuse sweating
c) drowsiness, lack of co-ordination
d) shivering and numbness in fingers and toes

8) A pneumothorax results when air from a lung over-expansion injury:
a) accumulates at the base of the neck
b) accumulates over the centre of the chest and presses on the heart
c) collapses a lung
d) enters the bloodstream

9) For which lung over-expansion injury would you give the patient emergency oxygen and apply other first aid for DCI steps?
a) air embolism
b) pneumothorax
c) medistinal emphysema
d) all of the above

10) Silent bubbles are:
a) small bubbles in the bloodstream after a dive that do not cause decompression sickness
b) bubbles that accumulate under the skin and cause subcutaneous emphysema
c) bubbles that interfere with nerve transmission and cause narcosis
d) bubbles found anywhere that a barotrauma occurs

11) A diver with headache, confusion, nausea and bright red lips and nails is most likely suffering from:
a) gas narcosis
b) hypocapnia
c) oxygen toxicity
d) carbon monoxide poisoning

12) An enriched air diver who makes a dive that exceeds an oxygen partial pressure of 1.4 – 1.6 ata runs an  unacceptable risk of:
a) convulsion and drowning due to pulmonary oxygen toxicity
b) a cough and burning chest due to pulmonary oxygen toxicity
c) convulsion and drowning due to CNS oxygen toxicity
d) a cough and burning chest due to CNS oxygen toxicity

Recreational Dive Planner

1) Using the RDP above ______ requires the use of special procedures including the conversion of actual depth to theoretical depth. To use theoretical depth tables, you must know the ______.
a) 300 metres (1000 feet) / altitude of the dive
b) 300 metres (1000 feet) / barometric pressure of the dive
c) 3000 metres (1000 feet) / planned dive depth
d) 2400 metres (8000 feet) / altitude of the dive

2) Another term for “theoretical tissue” is:
a) halftime
b) M-value
c) compartment
d) controlling tissue

3) Because the Recreational Dive Planner was designed using a faster “gas washout” tissue compartment than previous dive tables, it allows:
a) longer, deeper dives
b) shorter surface interval times
c) longer bottom times on repetitive dives
d) both b and c are correct

4) The pressure group designations on the Recreational Dive Planner are _________ with the pressure group letters used on other dive table models.
a) interchangeable
b) not interchangeable
c) equivalent
d) transferable when a conversion factor is used

5) The U.S. Navy tables use a ___________ to control repetitive diving to accommodate _____________ , whereas the RDP uses a ______________ because recreational dives are _______________.
a) 60 minutes halftime, stage decompression dives 120 minutes halftime, no stop dives
b) 60 minutes halftime, no stop dives 120 minutes halftime, air dives
c) 120 minutes halftime, stage decompression dives 60 halftime, no stop dives
d) 120 minute halftime, no stop dives 60 minute halftime, no stop dives

6) Maximum surfacing nitrogen levels in a model are
determined by:

a) the controlling compartment
b) the slow tissues
c) the M-values
d) the fast tissues

Use the eRDPml to answer the following:

7) What is the no decompression limit for a dive to 15m?
a) 72 minutes
b) 98 minutes
c) 56 minutes
d) 70 minutes

8) A diver exits the water in pressure group K, what is the pressure group after a 52 minute surface interval?
a) A
b) B
c) C
d) D

9) You have just made two dives, the first to 25m for 14 minutes and the second dive to 23m for 17 minutes a 45 minute surface interval between them. What is the minimum required surface interval for a dive to 21m for 17 minutes?
a) 35 minutes
b) 38 minutes
c) 39 minutes
d) 42 minutes

10) For your first dive of the day, you would like to dive for one hour. What’s the deepest depth possible for a one hour dive?
a) 16m
b) 18m
c) 20m
d) 22m

11) You’re planning a multilevel dive. The first level will be at 29m for 18 minutes. What is the no decompression limit for the next level at 20m?
a) 8 minutes
b) 10 minutes
c) 12 minutes
d) 14 minutes

12) You’re planning a multilevel dive. The first level is at 30m for 10 minutes. The second level is at 18m for 20 minutes.The third level is 10m for 72 minutes. What will your pressure group be when you reach the surface?
a) W
b) X
c) Y
d) Z

General Skills & Environment

1) In the ____________ hemisphere the major ocean currents flow anti-clockwise, while currents in the _____________ hemisphere flow clockwise.
a) western / eastern
b) eastern / western
c) northern / southern
d) southern / northern

2) A rip current is caused by:
a) water funneling back to sea through a narrow opening in a reef or sand bar
b) waves approaching shore at a slight angle
c) the rotation of the earth
d) offshore wind pushing top water out to sea

3) Aquatic life injury signs and symptoms may include:
a) severe pain
b) numbness or paralysis
c) cardiac arrest
d) all of the above

4) If you encounter a thermocline while descending, you will experience:
a) an abrupt transition from salt to fresh water
b) a cool current rising up from the bottom
c) a gradual change to salt water
d) an abrupt transition to colder water

5) Of those listed, select the most accurate method of measuring a short distance underwater
a) kick cycles
b) timed swim
c) air consumption
d) arm spans

6) When sharing a single air source, on each exchange you should take:
a) one breath
b) two breaths
c) three breaths
d) one breath if you’re the donor and two if you’re the receiver

7) The generally recommended knot for making a reliable, easy to untie loop in a rope is:
a) the square knot
b) the clove hitch
c) the bowline
d) the sheet bend

8) The generally preferred method for providing rescue breaths to a non-breathing diver at the surface is:
a) mouth to pocket mask
b) mouth to mouth
c) mouth to snorkel
d) mouth to nose

9) You’re navigating in limited visibility with a compass and your sense of direction tells you that you are off course, even though your compass says you are not. Generally you should:
a) disregard the compass and follow your sense of direction
b) trust the compass
c) compare your compass with your buddy’s to see if there is an error
d) none of the above

10) In the vast majority of circumstances, entering an overhead environment requires:
a) special equipment
b) special training
c) special procedures
d) all of the above

11) When breathing from a free flowing regulator:
a) do not seal your lips around the mouthpiece
b) make a continuous “ahhhhhh” sound
c) drop your weights and ascend
d) all of the above

12) The two forms of diver stress are:
a) physical and panic stress
b) psychological stress and panic stress
c) panic stress and anxiety stress
d) physical stress and psychological stress


1) Permanent markings that typically appear on a scuba cylinder are:
a) serial number and manufacturers designation
b) the working pressure
c) an alloy designation
d) all of the above

2) Compared to steel cylinders, aluminium cylinders typically:
a) have thicker walls
b) are often more buoyant
c) are less subject to weakening due to corrosion
d) all of the above

3) During hydrostatic testing, the tester fills the scuba cylinder with:
a) air
b) water
c) pure oxygen
d) the cylinder remains sealed

4) If a scuba cylinder is exposed to excessive heat, it should be ________________ before use.
a) visually inspected
b) hydrostatically / pressure tested
c) emptied and refilled with fresh air
d) repainted

5) When diving at altitudes above 300 metres the use of a(n) _________ depth gauge will give theoretical depths rather than actual depth.
a) capillary
b) closed bourdon tube
c) open bourdon tube
d) oil filled

6) A burst disk is intended to:
a) rupture at 7 bar over a cylinder’s working pressure
b) prevent an over-inflated BCD from rupturing
c) rupture at pressure between 125% and 166% of a cylinder’s working pressure
d) open more easily than a BCD’s normal exhaust valve

7) The type of scuba most commonly used by recreational divers is called:
a) open circuit scuba
b) semi-closed circuit scuba
c) closed circuit scuba
d) none of the above

8) The second stage of a modern scuba regulator will most likely have either a(n) __________ or _________ valve.
a) downstream / pilot
b) upstream / pilot
c) piston / diaphragm
d) downstream / flutter

9) An upstream valve is one that:
a) opens against the flow of air
b) opens with the flow of air
c) may open with or against the flow of air, depending on the design
d) is any valve in the first stage

10) A regulator that is designed so that tank air pressure either assists or resists the opening of valves is called:
a) a diaphragm regulator
b) a piston regulator
c) a balanced regulator
d) an unbalanced regulator

11) An analog SPG works based on the principle that:
a) a sealed tube exposed to pressure tends to coil more tightly
b) pressure in a C-shaped tube tends to straighten it
c) a spring-balanced piston resists movement
d) a diaphram’s flexing under pressure can move a needle

12) When using dive computers:
a) you have a more valid decompression model than when diving with tables
b) each diver should have a personal computer
c) you can avoid many of the guidelines required when diving with tables
d) all of the above