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PADI OPEN WATER DIVER – FINAL EXAM
REVIEW**100 PRACTICE QUESTIONS WITH
VERIFIED ANSWERS & DETAILED
RATIONALES**DIVE PHYSICS • PHYSIOLOGY •
EQUIPMENT • DECOMPRESSION THEORY • DIVE
PLANNING • SAFETY • ENVIRONMENT**HIGH-YIELD
CONTENT • FIRST-TIME PASS**
# TABLE OF CONTENTS
| Section | Topic | Questions |
|---------|-------|-----------|
| 1 | Dive Physics (Pressure, Buoyancy, Gas Laws) | 1–20 |
| 2 | Dive Physiology (Air Spaces, Circulation, Nitrogen, Oxygen) | 21–
35 |
| 3 | Decompression Theory & Dive Tables | 36–50 |
| 4 | Dive Equipment | 51–65 |
| 5 | Dive Planning & Safety | 66–80 |
| 6 | Aquatic Environment (Marine Life, Currents, Weather) | 81–90 |
| 7 | Emergency Procedures & Rescue | 91–100 |
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# SECTION 1: DIVE PHYSICS (Pressure, Buoyancy, Gas Laws) –
Questions 1–20
**1. Water is approximately how many times denser than air?**
A) 100 times
B) 400 times
C) 800 times
D) 1,000 times
**Answer: C**
*Rationale:* Water is about 800 times denser than air. This density
affects buoyancy, drag, and heat loss.
**2. For every 10 meters (33 feet) of seawater, pressure increases by:**
A) 1 atmosphere (ATA)
B) 2 atmospheres (ATA)
C) 0.5 atmospheres (ATA)
D) 5 atmospheres (ATA)
**Answer: A**
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*Rationale:* Pressure increases by 1 bar/ATA per 10 meters (33 feet) of
seawater. At 10 meters, pressure = 2 ATA (1 from atmosphere + 1 from
water).
**3. A diver at 20 meters (66 feet) experiences what ambient
pressure?**
A) 2 ATA
B) 3 ATA
C) 4 ATA
D) 1 ATA
**Answer: B**
*Rationale:* Pressure at surface = 1 ATA. Each 10 m adds 1 ATA. At 20
m: 1 + 2 = 3 ATA.
**4. Absolute pressure is defined as:**
A) Gauge pressure plus atmospheric pressure
B) Atmospheric pressure minus gauge pressure
C) Only the pressure from water
D) Only atmospheric pressure
**Answer: A**
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*Rationale:* Absolute pressure = gauge pressure (from water) +
atmospheric pressure (1 ATA at sea level). Most dive calculations use
absolute pressure.
**5. According to Boyle's Law, if you descend from the surface to 10
meters (2 ATA), the volume of a flexible air-filled space will:**
A) Double
B) Remain the same
C) Reduce to half (1/2)
D) Reduce to one quarter (1/4)
**Answer: C**
*Rationale:* Boyle's Law: P₁V₁ = P₂V₂. At surface: 1 ATA × V₁. At 10
m: 2 ATA × V₂. V₂ = V₁ × (1/2). Volume decreases as pressure increases.
**6. A diver fills a BCD (buoyancy compensator device) at 20 meters (3
ATA) and then ascends to the surface (1 ATA). What happens to the air
volume in the BCD?**
A) Volume decreases to 1/3
B) Volume triples (3×)
C) Volume remains constant
D) Volume increases to 6×
**Answer: B**
PADI OPEN WATER DIVER – FINAL EXAM
REVIEW**100 PRACTICE QUESTIONS WITH
VERIFIED ANSWERS & DETAILED
RATIONALES**DIVE PHYSICS • PHYSIOLOGY •
EQUIPMENT • DECOMPRESSION THEORY • DIVE
PLANNING • SAFETY • ENVIRONMENT**HIGH-YIELD
CONTENT • FIRST-TIME PASS**
# TABLE OF CONTENTS
| Section | Topic | Questions |
|---------|-------|-----------|
| 1 | Dive Physics (Pressure, Buoyancy, Gas Laws) | 1–20 |
| 2 | Dive Physiology (Air Spaces, Circulation, Nitrogen, Oxygen) | 21–
35 |
| 3 | Decompression Theory & Dive Tables | 36–50 |
| 4 | Dive Equipment | 51–65 |
| 5 | Dive Planning & Safety | 66–80 |
| 6 | Aquatic Environment (Marine Life, Currents, Weather) | 81–90 |
| 7 | Emergency Procedures & Rescue | 91–100 |
,2|Page
# SECTION 1: DIVE PHYSICS (Pressure, Buoyancy, Gas Laws) –
Questions 1–20
**1. Water is approximately how many times denser than air?**
A) 100 times
B) 400 times
C) 800 times
D) 1,000 times
**Answer: C**
*Rationale:* Water is about 800 times denser than air. This density
affects buoyancy, drag, and heat loss.
**2. For every 10 meters (33 feet) of seawater, pressure increases by:**
A) 1 atmosphere (ATA)
B) 2 atmospheres (ATA)
C) 0.5 atmospheres (ATA)
D) 5 atmospheres (ATA)
**Answer: A**
,3|Page
*Rationale:* Pressure increases by 1 bar/ATA per 10 meters (33 feet) of
seawater. At 10 meters, pressure = 2 ATA (1 from atmosphere + 1 from
water).
**3. A diver at 20 meters (66 feet) experiences what ambient
pressure?**
A) 2 ATA
B) 3 ATA
C) 4 ATA
D) 1 ATA
**Answer: B**
*Rationale:* Pressure at surface = 1 ATA. Each 10 m adds 1 ATA. At 20
m: 1 + 2 = 3 ATA.
**4. Absolute pressure is defined as:**
A) Gauge pressure plus atmospheric pressure
B) Atmospheric pressure minus gauge pressure
C) Only the pressure from water
D) Only atmospheric pressure
**Answer: A**
, 4|Page
*Rationale:* Absolute pressure = gauge pressure (from water) +
atmospheric pressure (1 ATA at sea level). Most dive calculations use
absolute pressure.
**5. According to Boyle's Law, if you descend from the surface to 10
meters (2 ATA), the volume of a flexible air-filled space will:**
A) Double
B) Remain the same
C) Reduce to half (1/2)
D) Reduce to one quarter (1/4)
**Answer: C**
*Rationale:* Boyle's Law: P₁V₁ = P₂V₂. At surface: 1 ATA × V₁. At 10
m: 2 ATA × V₂. V₂ = V₁ × (1/2). Volume decreases as pressure increases.
**6. A diver fills a BCD (buoyancy compensator device) at 20 meters (3
ATA) and then ascends to the surface (1 ATA). What happens to the air
volume in the BCD?**
A) Volume decreases to 1/3
B) Volume triples (3×)
C) Volume remains constant
D) Volume increases to 6×
**Answer: B**
