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PADI Open Water Diver Newest Exam Preparation
With Complete Questions And Correct Answers With
Rationales Already Graded A+Brand New Version!!
Question 1
The absolute pressure at a depth of 33 feet in seawater is most nearly
equivalent to which of the following values?
A) 1 atmosphere
B) 2 atmospheres
C) 3 atmospheres
D) 4 atmospheres
Answer: B) 2 atmospheres. At the surface, the diver experiences 1
atmosphere of absolute pressure. In seawater, every 33 feet of depth
adds another atmosphere of pressure due to the weight of the water
column above. Therefore, at 33 feet, the total absolute pressure equals
the surface pressure plus the hydrostatic pressure, yielding 2
atmospheres absolute.
Question 2
If a flexible container holds 10 liters of air at the surface, what will its
volume be at a depth of 66 feet in seawater?
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A) 5 liters
B) 3.3 liters
C) 2.5 liters
D) 1.25 liters
Answer: B) 3.3 liters. At 66 feet, the absolute pressure is 3 atmospheres
(1 atmosphere from the surface plus 2 atmospheres from the water
depth). Boyle's Law dictates that pressure and volume are inversely
proportional at a constant temperature. Thus, the new volume is 10
liters divided by 3, equaling approximately 3.3 liters.
Question 3
Which of the following statements correctly describes Dalton's Law in
the context of scuba diving?
A) The total pressure of a gas mixture is the sum of the partial pressures
of each component gas.
B) The solubility of a gas in a liquid is proportional to its partial
pressure.
C) The volume of a gas is inversely proportional to its absolute pressure.
D) The rate of diffusion of a gas is inversely proportional to the square
root of its molecular weight.
Answer: A) The total pressure of a gas mixture is the sum of the partial
pressures of each component gas. Dalton's Law is foundational for
understanding partial pressures in breathing gas mixtures. It explains
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why the partial pressure of oxygen and nitrogen increases with depth,
which has implications for oxygen toxicity and nitrogen narcosis.
Question 4
Henry's Law is most directly relevant to which of the following diving
phenomena?
A) Nitrogen narcosis
B) Decompression sickness
C) Oxygen toxicity
D) Barotrauma of the ears
Answer: B) Decompression sickness. Henry's Law states that the amount
of gas dissolved in a liquid is proportional to the partial pressure of that
gas in contact with the liquid. During a dive, increased pressure causes
more nitrogen to dissolve in the blood and tissues. If the diver ascends
too quickly, the reduced pressure causes this dissolved nitrogen to form
bubbles, leading to decompression sickness.
Question 5
What is the primary physiological risk associated with breathing air at a
depth exceeding approximately 100 feet?
A) Oxygen toxicity
B) Nitrogen narcosis
C) Carbon dioxide toxicity
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D) Carbon monoxide poisoning
Answer: B) Nitrogen narcosis. At depths greater than 100 feet, the
elevated partial pressure of nitrogen produces a narcotic effect on the
central nervous system. This condition, often compared to alcohol
intoxication, impairs judgment, coordination, and cognitive function.
Oxygen toxicity is more likely at shallower depths when using enriched
air, while carbon dioxide and carbon monoxide issues are generally
related to gas contamination or inadequate ventilation.
Question 6
The term "partial pressure" is best defined as:
A) The pressure exerted by a single gas in a mixture as if it occupied the
total volume alone.
B) The total pressure exerted by all gases in a mixture.
C) The pressure difference between the ambient water pressure and
the gas pressure in the lungs.
D) The pressure required to inflate a buoyancy compensator at depth.
Answer: A) The pressure exerted by a single gas in a mixture as if it
occupied the total volume alone. This is the formal definition of partial
pressure. It is calculated by multiplying the fraction of the gas in the
mixture by the total absolute pressure of the mixture. This concept is
crucial for understanding the physiological effects of compressed gases
during diving.
PADI Open Water Diver Newest Exam Preparation
With Complete Questions And Correct Answers With
Rationales Already Graded A+Brand New Version!!
Question 1
The absolute pressure at a depth of 33 feet in seawater is most nearly
equivalent to which of the following values?
A) 1 atmosphere
B) 2 atmospheres
C) 3 atmospheres
D) 4 atmospheres
Answer: B) 2 atmospheres. At the surface, the diver experiences 1
atmosphere of absolute pressure. In seawater, every 33 feet of depth
adds another atmosphere of pressure due to the weight of the water
column above. Therefore, at 33 feet, the total absolute pressure equals
the surface pressure plus the hydrostatic pressure, yielding 2
atmospheres absolute.
Question 2
If a flexible container holds 10 liters of air at the surface, what will its
volume be at a depth of 66 feet in seawater?
,2|Page
A) 5 liters
B) 3.3 liters
C) 2.5 liters
D) 1.25 liters
Answer: B) 3.3 liters. At 66 feet, the absolute pressure is 3 atmospheres
(1 atmosphere from the surface plus 2 atmospheres from the water
depth). Boyle's Law dictates that pressure and volume are inversely
proportional at a constant temperature. Thus, the new volume is 10
liters divided by 3, equaling approximately 3.3 liters.
Question 3
Which of the following statements correctly describes Dalton's Law in
the context of scuba diving?
A) The total pressure of a gas mixture is the sum of the partial pressures
of each component gas.
B) The solubility of a gas in a liquid is proportional to its partial
pressure.
C) The volume of a gas is inversely proportional to its absolute pressure.
D) The rate of diffusion of a gas is inversely proportional to the square
root of its molecular weight.
Answer: A) The total pressure of a gas mixture is the sum of the partial
pressures of each component gas. Dalton's Law is foundational for
understanding partial pressures in breathing gas mixtures. It explains
,3|Page
why the partial pressure of oxygen and nitrogen increases with depth,
which has implications for oxygen toxicity and nitrogen narcosis.
Question 4
Henry's Law is most directly relevant to which of the following diving
phenomena?
A) Nitrogen narcosis
B) Decompression sickness
C) Oxygen toxicity
D) Barotrauma of the ears
Answer: B) Decompression sickness. Henry's Law states that the amount
of gas dissolved in a liquid is proportional to the partial pressure of that
gas in contact with the liquid. During a dive, increased pressure causes
more nitrogen to dissolve in the blood and tissues. If the diver ascends
too quickly, the reduced pressure causes this dissolved nitrogen to form
bubbles, leading to decompression sickness.
Question 5
What is the primary physiological risk associated with breathing air at a
depth exceeding approximately 100 feet?
A) Oxygen toxicity
B) Nitrogen narcosis
C) Carbon dioxide toxicity
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D) Carbon monoxide poisoning
Answer: B) Nitrogen narcosis. At depths greater than 100 feet, the
elevated partial pressure of nitrogen produces a narcotic effect on the
central nervous system. This condition, often compared to alcohol
intoxication, impairs judgment, coordination, and cognitive function.
Oxygen toxicity is more likely at shallower depths when using enriched
air, while carbon dioxide and carbon monoxide issues are generally
related to gas contamination or inadequate ventilation.
Question 6
The term "partial pressure" is best defined as:
A) The pressure exerted by a single gas in a mixture as if it occupied the
total volume alone.
B) The total pressure exerted by all gases in a mixture.
C) The pressure difference between the ambient water pressure and
the gas pressure in the lungs.
D) The pressure required to inflate a buoyancy compensator at depth.
Answer: A) The pressure exerted by a single gas in a mixture as if it
occupied the total volume alone. This is the formal definition of partial
pressure. It is calculated by multiplying the fraction of the gas in the
mixture by the total absolute pressure of the mixture. This concept is
crucial for understanding the physiological effects of compressed gases
during diving.
