Free IDC Dive Theory & Safety Standards Questions and Answers 1 — Questions and Answers

Question 1: What is the primary purpose of dive tables?

To measure water temperature.
To plan safe dive profiles (Correct answer)
To record marine species.
To schedule dive trips.

Correct answer: To plan safe dive profiles

Dive tables are essential tools used by scuba divers to plan and execute dives safely within no-decompression limits. They help divers calculate maximum bottom times and surface intervals based on depth, preventing the accumulation of nitrogen that could lead to decompression sickness.

Question 2: What causes decompression sickness?

Holding breath underwater.
Rapid ascent causing gas bubbles (Correct answer)
Cold water temperature.
Wearing heavy gear.

Correct answer: Rapid ascent causing gas bubbles

Decompression sickness (DCS), or "the bends," occurs when a diver ascends too quickly, causing dissolved inert gases (primarily nitrogen) in the body to form bubbles in tissues and the bloodstream. These bubbles can lead to a range of symptoms, from joint pain to neurological impairment, as the body fails to off-gas nitrogen safely.

Question 3: What is the recommended ascent rate to prevent decompression sickness?

100 feet per minute.
No faster than 30 feet per minute (Correct answer)
No ascent needed.
Immediate surfacing.

Correct answer: No faster than 30 feet per minute

A recommended ascent rate of no faster than 30 feet per minute (or 9 meters per minute) is crucial for preventing decompression sickness in scuba diving. This slow ascent allows the body sufficient time to safely off-gas dissolved nitrogen, minimizing the formation of harmful bubbles in the tissues.

Question 4: Why is a safety stop important during a dive?

To rest underwater.
To reduce nitrogen levels safely (Correct answer)
To check equipment.
To take photos.

Correct answer: To reduce nitrogen levels safely

During a dive, nitrogen gas dissolves into a diver's tissues. A safety stop, typically a 3-5 minute stop at 15-20 feet (3-6 meters) near the end of a dive, allows the body to off-gas some of this dissolved nitrogen more slowly. This controlled off-gassing significantly reduces the risk of decompression sickness (DCS), making the ascent safer.

Question 5: What is nitrogen narcosis?

Sunburn from reflection.
Impaired judgment underwater (Correct answer)
Water intoxication.
Muscle cramps.

Correct answer: Impaired judgment underwater

Nitrogen narcosis, often called "rapture of the deep," is a reversible alteration in consciousness that occurs while diving at depth. It's caused by the increased partial pressure of nitrogen gas affecting the central nervous system. Symptoms can range from mild euphoria to impaired judgment, disorientation, and reduced motor skills, posing significant safety risks to divers.

Question 6: How often should dive equipment be inspected?

Once a year.
Before every dive (Correct answer)
Never.
Only after a problem occurs.

Correct answer: Before every dive

Dive equipment is life support equipment, and its proper function is paramount for diver safety. Inspecting gear before every dive ensures all components are in good working order, free from damage, and correctly assembled. This routine check helps identify potential issues proactively, preventing equipment malfunctions that could lead to dangerous situations underwater.

Question 7: What does the term 'no-decompression limit' mean?

Minimum surface time needed.
Max time without decompression stop (Correct answer)
Total dive time.
Time to descend.

Correct answer: Max time without decompression stop

The no-decompression limit (NDL) refers to the maximum amount of time a diver can spend at a given depth without needing to perform mandatory decompression stops during ascent. Staying within these limits, as defined by dive tables or computers, ensures that the body off-gasses dissolved nitrogen safely during a normal ascent, significantly reducing the risk of decompression sickness.

Question 8: Why is buddy diving recommended?

For competition.
For mutual safety (Correct answer)
To share equipment.
For fun only.

Correct answer: For mutual safety

Buddy diving is a cornerstone of dive safety, as it provides a system of mutual support and assistance. A dive buddy can help with equipment checks, monitor air supply, assist in emergencies, and provide a sense of security. This partnership significantly enhances safety by ensuring there's always someone to rely on if a problem arises underwater.

Question 9: What should you do if you suspect decompression sickness?

Continue diving.
Seek medical help immediately (Correct answer)
Ignore symptoms.
Drink alcohol.

Correct answer: Seek medical help immediately

Decompression sickness (DCS) is a serious medical condition that requires prompt treatment. If a diver suspects DCS, immediate medical attention is crucial, typically involving recompression therapy in a hyperbaric chamber. Delaying treatment can lead to more severe symptoms, permanent injury, or even death, making rapid response essential for a positive outcome.

Free IDC Dive Theory & Safety Standards Questions and Answers 1

What is the primary purpose of dive tables?