SDI Final Exam

A scuba cylinder that normally lasts one hour at the surface will last _______ minutes at 20 meters/66 feet. 1: 30 2: 20 3: 15 4: 10

20 Explanation: A scuba cylinder that normally lasts one hour at the surface will last 20 minutes at 20 m/66 ft.

Among the best ways to prevent decompression sickness (DCS): 1: Remain well within your dive computer's no-decompression limit. 2: Ascend no faster than the rate allowed by the dive computer. 3: Make a safety stop of between three and five minutes at a depth of 3-6 m/10-20 ft. 4: All of the above.

All of the above.

As you descend: 1: Colors appear to fade. 2: Reds and oranges are among the first colors to disappear. 3: At 30 m/99 ft, little color remains other than blues, grays, blacks and whites. 4: All of the above.

All of the above.

Contributing factors to decompression sickness can include: 1: Rapid ascents. 2: 'Pushing" or exceeding your computer's no-decompression limits. 3: Heavy exertion and/or dehydration. 4: All of the above.

All of the above.

Which of the following is/are true? 1: Tides can make the water at a particular dive site noticeably deeper or shallower than you may have experienced previously. 2: Tidal currents can be very strong, making diving difficult or even dangerous. 3: Strong tidal currents can have an adverse effect on visibility. 4: All of the above.

All of the above.

Which of the following is not true? Divers should equalize: 1: Preemptively before descent. 2: Well before feeling any pain or discomfort. 3: As soon as they feel any pain or discomfort. 4: Early and often during descent.

As soon as they feel any pain or discomfort.

If symptoms such as euphoria, anxiety or motor skill impairment make you suspect you are suffering from narcosis, the best response is to: 1: Perform an Emergency Swimming Ascent (ESA). 2: Ascend to a depth at which the symptoms disappear. 3: Switch to your buddy's alternate air source. 4: None of the above.

Ascend to a depth at which the symptoms disappear.

Which of the following is/are important features of a weight system? 1: The ability to quickly and reliably jettison at least enough weight to make the wearer positively buoyant at the surface or at depth. 2: The ability to carry a minimum of at least 25 kg/55 lbs of weight. 3: The ability to easily adjust the amount of weight used. 4: Both the first and third answers are correct.

Both the first and third answers are correct. Explanation: There is no established minimum capacity for a weight system. So long as it has a quick-release mechanism and is easy to adjust the amount of weight used, any system that enables you to carry enough ballast to be properly weighted is fine.

Among the limitations of full foot fins: 1: They are not well suited for colder-water diving. 2: There are no full-foot fins sufficiently powerful for use with scuba equipment. 3: They are not well suited for entries from rocky shores. 4: Both the first and third answers are correct.

Both the first and third answers are correct. Explanation: Full foot fins are not well suited for diving in cold water or from rocky shores. Higher-end full-foot fins may have sufficient power for overcoming the additional drag of scuba equipment (although many full-foot fins do not).

Which of the following statements is true? There may be more than one correct answer. 1: Water is 400 times denser than air. 2: Water is 800 times denser than air. 3: Sound travels about four times faster underwater. 4: Both the second and the third answer are correct.

Both the second and the third answer are correct.

Objects under water appear: 1: The same size as they do on land. 2: Twice as large as they do on land. 3: Closer and larger than they do on land. 4: Smaller and farther away than they do on land.

Closer and larger than they do on land.

Seasickness is caused by: 1: Factors such as smell of salt water and the sound of boat engines. 2: A change in equilibrium in the middle ear. 3: An elevation in adrenaline levels caused by anxiety over diving. 4: None of the above.

Correct Answer: A change in equilibrium in the middle ear. Explanation: Seasickness is caused by a change in equilibrium in the middle ear.

The ABC pre-dive check acronym refers to: 1: Air on; BC inflated; Clear to enter. 2: Airway open; BC inflated; Computer checked and activated. 3: Air on; BC inflated; Computer checked and activated. 4: Airway open; Belt adjusted; Clear to enter.

Correct Answer: Air on; BC inflated; Computer checked and activated. Explanation: The ABC pre-dive check acronym refers to: Air on; BC inflated; Computer checked and activated.

If you are unable to make a required decompression stop: 1: Breathe pure oxygen for at least 30 minutes. 2: Monitor for signs and symptoms of decompression sickness for the next 24 hours. 3: Do not dive or fly for at least 24 hours. 4: All of the above.

Correct Answer: All of the above. Explanation: All of the supplied answers are correct.

Among the things dive buddies must agree upon prior to a dive are: 1: Depth and time limits. 2: Planned activity. 3: Procedure to follow if separated. 4: All of the above.

Correct Answer: All of the above. Explanation: All of the supplied answers are things buddies should agree upon prior to the dive.

Key steps in descending and ascending include: 1: Agreeing with your buddy before doing either. 2: Staying within your dive computer's allowable ascent rate. 3: Using your BC to help control your rate of descent or ascent. 4: All of the above.

Correct Answer: All of the above. Explanation: All of the supplied answers are true.

In terms of what BCs can help divers do, all of the following are true except: 1: Achieve positive buoyancy at the surface and maintain neutral buoyancy under water. 2: Provide a central attachment point for cylinders, regulators and accessories. 3: Allow divers to enjoy elevator-like rides to the surface 4: Generally incorporate a weight system.

Correct Answer: Allow divers to enjoy elevator-like rides to the surface Explanation: Using a BC to initiate a buoyant ascent can invite dangerously rapid ascent rates.

The most accurate place to conduct a weight check is: 1: At the surface, at the beginning of the dive. 2: At the deepest point reached during the dive. 3: At safety-stop depth, at the end of the dive. 4: None of the above.

Correct Answer: At safety-stop depth, at the end of the dive. Explanation: The most accurate place to conduct a weight check is at safety-stop depth, at the end of the dive.

Before you can remove the regulator from your scuba cylinder, you must: 1: Turn the air all the way off. 2: Depressurize the system by depressing and holding one of the purge buttons. 3: Make sure the low-pressure inflator hose remains connected to the BC power inflator. 4: Both the first and second answers are correct

Correct Answer: Both the first and second answers are correct Explanation: You must make sure the low-pressure inflator hose is disconnected from the BC power inflator.

Divers should plan to ascend as soon as the first diver: 1: Reaches his minimum ascent pressure. 2: Reaches his maximum allowable dive time. 3: Reaches his maximum agreed-upon depth. 4: Both the first and second answers are correct.

Correct Answer: Both the first and second answers are correct. Explanation: You can continue your dive after reaching your maximum agreed-upon depth, so long as you do not exceed it.

Activities that may increase the risk of decompression sickness include: 1: Alcohol use. 2: Computer use. 3: Drug use. 4: Both the first and third answers are correct.

Correct Answer: Both the first and third answers are correct. Explanation: Activities that may increase the risk of decompression sickness include alcohol and drug use.

Among the key points in doing a flutter kick correctly: 1: Keep your knees as straight as possible. 2: Emulate the leg movements you make when pedaling a bicycle. 3: Keep your toes pointed. 4: Both the first and third answers are correct.

Correct Answer: Both the first and third answers are correct. Explanation: The key points in doing a flutter kick correctly include keeping your knees straight and your toes pointed.

If you suspect that you or another diver is suffering from decompression sickness. 1: Drive yourself (or the affected diver) to the closest recompression chamber. 2: Activate the Emergency Medical Service (EMS) system. 3: Contact the Divers Alert Network (DAN). 4: Both the second and third answers are correct.

Correct Answer: Both the second and third answers are correct. Explanation: If you suspect that you or another diver is suffering from decompression sickness, activate the Emergency Medical Service (EMS) system and contact the Divers Alert Network (DAN). You may be directred to take the patient to the closest hyperbaric chamber; however, this is not a certainty.

Not allowing alternate-air-source second stages, instrument consoles and other equipment to dangle freely: 1: Does little to protect equipment from damage. 2: Helps protect equipment from damage. 3: Helps reduce the risk of entanglement. 4: Both the second and third answers are correct.

Correct Answer: Both the second and third answers are correct. Explanation: Not allowing alternate-air-source second stages, instrument consoles and other equipment to dangle freely actually does quite a bit to help prevent equipment damage.

Air passages such as your trachea (windpipe), which may contain air your body can't use, are known as: 1: Brachia. 2: Bronchials. 3: Dead air spaces. 4: Restricted orifices.

Correct Answer: Dead air spaces. Explanation: Air passages such as your trachea (windpipe), which may contain air your body can't use, are known as dead air spaces.

Any time a regulator is out of your mouth under water, you should: 1: Hold your breath to conserve your remaining air. 2: Exhale a small, steady stream of bubbles. 3: Exhale forcefully to purge your lungs of air. 4: None of the above.

Correct Answer: Exhale a small, steady stream of bubbles. Explanation: Any time a regulator is out of your mouth under water, you should exhale a small, steady stream of bubbles.

Which of the following is among the most effective means of relieving a leg cramp once it has occurred? 1: Change to a different style of kick. 2: Remove the fin from the affected leg and kick using just the remaining fin. 3: Grasp the fin tip of the affected leg and pull towards you while straightening the leg. This stretches the calf muscle. 4: None of the above.

Correct Answer: Grasp the fin tip of the affected leg and pull towards you while straightening the leg. This stretches the calf muscle. Explanation: The most effective means of relieving a leg cramp once it has occurred is to grasp the fin tip of the affected leg and pull towards you while straightening the leg. This stretches the calf muscle.

The reciprocal mark(s) on your compass's bezel: 1: Are required by law. 2: Are set at 90 degrees from the index marks. 3: Help you to find your way back to your starting point without having to surface to take a new heading. 4: Are set in line with the lubber line.

Correct Answer: Help you to find your way back to your starting point without having to surface to take a new heading. Explanation: The reciprocal marks on your compass's bezel help you to find your way back to your starting point without having to surface to take a new heading.

When pressurizing your scuba system (i.e., turning the air on), you should: 1: Look directly at the submersible pressure gauge (SPG) to make sure the cylinder is full. 2: Hold the SPG facing down or away from you. 3: Keep at least one second stage purge button depressed. 4: None of the above.

Correct Answer: Hold the SPG facing down or away from you. Explanation: For safety, when pressurizing your scuba system (i.e., turning the air on), you should hold the SPG facing down or away from you.

Scuba cylinders must be: 1: Hydrostatically tested every four years and visually inspected every six months. 2: Hydrostatically tested and visually inspected at intervals determined by local laws and regulations, or prevailing standards of practice. 3: Hydrostatically tested every year and visually inspected every five years. 4: None of the above.

Correct Answer: Hydrostatically tested and visually inspected at intervals determined by local laws and regulations, or prevailing standards of practice. Explanation: Scuba cylinders must periodically undergo periodic visual inspections and hydrostatic tests, at intervals determined by local laws and regulations, or prevailing standards of practice.

The backward roll: 1: Is less disorienting than a giant stride. 2: Works best in colder water. 3: Is chiefly a small-boat entry. 4: Cannot be used in salt water.

Correct Answer: Is chiefly a small-boat entry. Explanation: The backward roll is chiefly a small-boat entry.

Which of the following does not help to explain why, when both options are available, an alternate-air-source ascent is preferable to any type of independent emergency ascent? 1: It helps get the out-of-air diver to the surface faster. 2: It helps ensure both donor and receiver can breathe continuously throughout the ascent. 3: Air permitting, it allows the divers to make a slow ascent. 4: Air permitting, it allows the divers to make a safety stop.

Correct Answer: It helps get the out-of-air diver to the surface faster. Explanation: An alternate-air-source ascent will not necessarily get an out-of-air diver to the surface any faster. In fact, the ability to make slow ascents and safety stops is among its benefits.

If you cannot reunite with a missing buddy: 1: Initiate an underwater search, using an expanding square pattern. 2: Seek assistance from the closest military base. 3: Leave underwater searches to trained professionals. 4: None of the above.

Correct Answer: Leave underwater searches to trained professionals. Explanation: If you cannot reunite with a missing buddy, seek assistance. Leave underwater searches to trained professionals.

You will generally get the longest bottom times by: 1: Making the shallowest dives first. 2: Making the deepest dives first. 3: Waiting no more than 90 minutes between dives. 4: Doing no more than two dives a day.

Correct Answer: Making the deepest dives first. Explanation: You will generally get the longest bottom times by making the deepest dives first.

If you become separated from your buddy, search for no more than ________ ________, then surface. 1: One minute 2: Two minute 3: Three minutes 4: Five minutes

Correct Answer: One minute Explanation: If you become separated from your buddy, search for no more than one minute, then surface.

Which of the following is not true? When Clearing a mask, you should: 1: Pull out slightly at the base of the mask to create a space for water to exit. 2: Inhale through your mouth, but exhale through your nose. 3: Take as many breaths as needed to clear the mask completely. 4: Look up during the last exhalation to make the bottom of the mask skirt the lowest point.

Correct Answer: Pull out slightly at the base of the mask to create a space for water to exit. Explanation: Pulling out slightly at the base of the mask to 'create a space for water to exit' may allow as much water to enter as exit. Instead, just push in at the tops and sides.

The two most common methods for recovering a regulator that has fallen behind your shoulder are: 1: Reach, Blast 2: Sweep, Purge 3: Reach, Sweep 4: Sweep, Blast

Correct Answer: Reach, Sweep Explanation: The two most common methods for recovering a regulator that has fallen behind your shoulder are the reach and the sweep.

Among the easiest ways to don a heavy weight belt, at the surface or under water, is to: 1: Pass it under your feet. 2: Roll into it. 3: Back into it. 4: None of the above.

Correct Answer: Roll into it. Explanation: Among the easiest ways to don a heavy weight belt, at the surface or under water, is to roll into it.

Only a truly redundant alternate air source, such as a pony/bail-out bottle, can be used for: 1: Self rescue. 2: Gaining experience. 3: Wreck diving. 4: Underwater photography.

Correct Answer: Self rescue. Explanation: Only an independent, alternate air source can be used for self rescue.

At the first sign of overexertion: 1: Abort the dive. 2: Stop, relax and breathe deeply. 3: Signal to the shore or boat for assistance. 4: Both the first and third answers are correct.

Correct Answer: Stop, relax and breathe deeply. Explanation: At the first sign of overexertion. stop, relax and breathe deeply.

Under water, the easiest way to remove and replace a scuba unit is to: 1: Pass it over your head. 2: Take it off and put it on like a jacket. 3: Stand on it. 4: None of the above.

Correct Answer: Take it off and put it on like a jacket. Explanation: Under water, the easiest way to remove and replace a scuba unit is to take it off and put it on like a jacket.

The single most important feature to consider when purchasing a scuba regulator is: 1: How well it performs in controlled laboratory testing. 2: A second-stage adjustment knob to ensure ease of breathing. 3: The availability of regular, professional maintenance. 4: Both the first and second answers are correct.

Correct Answer: The availability of regular, professional maintenance. Explanation: Virtually all better-quality regulators provide more-than-adequate performance for recreational diving right out of the box. The key is the ability to get regular, professional maintenance, so that you can maintain that level of performance over the life of the regulator.

During an independent emergency ascent, you should stop periodically and attempt to inhale through your regulator because: 1: Doing so reduces the risk of decompression sickness. 2: Doing so reduces the risk of lung-overpressure injuries. 3: The decreasing pressure may allow your regulator to function, even if it could not do so at depth. 4: The air in your cylinder will expand on ascent, allowing you to breathe.

Correct Answer: The decreasing pressure may allow your regulator to function, even if it could not do so at depth. Explanation: If your regulator will not function at depth, it may not mean you are out of air; only that the ambient pressure is too great to allow your regulator to function. This may change as you ascend.

To successfully vent air from a BC: 1: You need to be in a perfectly vertical position. 2: The exhaust valve you will be using must be the highest point on the air cell. 3: You must activate the BC's overpressure relief valve. 4: None of the above.

Correct Answer: The exhaust valve you will be using must be the highest point on the air cell. Explanation: To successfully vent air from a BC, the exhaust valve you will be using must be the highest point on the air cell.

The primary function of a dive flag is to: 1: Help prevent buddy separation. 2: Warn boaters that there are divers in the area. 3: Enable lifeguards on shore to track the location of buddy teams. 4: Both the first and third answers are correct.

Correct Answer: Warn boaters that there are divers in the area. Explanation: The primary function of a dive flag is to warn boaters that there are divers in the area.

Diving safety begins with _______ ________ and _______ _______. 1: environmental awareness, self awareness 2: personal awareness, buddy dependence 3: environmental awareness, self sufficiency 4: personal awareness, self sufficiency

Correct Answer: personal awareness, self sufficiency Explanation: Diving safety begins with personal awareness and self sufficiency.

Additional features common to many dive computers include all of the following except: Answer 1: The ability to display dive log data and to upload that data to a laptop or desktop computer. Answer 2: The ability to monitor a diver's exposure to air, Nitrox and Trimix. Answer 3: The ability to project no-decompression limits for upcoming dives. Answer 4: Bar graphs that provide a visual representation of a diver's exposure to nitrogen and other gasses.

Correct Answer: The ability to monitor a diver's exposure to air, Nitrox and Trimix. Explanation: While most dive computers can monitor a diver's exposure to air and Nitrox, few can track exposure to Trimix (an oxygen/nitrogen/helium mixture).

What should you do if you suddenly feel ill and/or develop a headache during a scuba dive? 1: Consult a physician as soon as possible. 2: End the dive and make a normal, slow ascent. 3: Ascend to a depth where the symptoms dissipate. 4: Both the first and third answers are correct.

End the dive and make a normal, slow ascent.

Any time you cannot inhale while scuba diving (such as when a regulator is out of your mouth), you must be: 1: Holding your breath to conserve your remaining air. 2: Exhaling. 3: Monitoring your depth to avoid accidental ascents while breath holding. 4: Both the first and third answers are correct.

Exhaling.

To help prevent mildew, store equipment in a sealed container before it dries. 1: True 2: False

False

Psoriacysts produce toxins that, when touched, can produce symptoms ranging from a mild rash or sting to anaphylactic shock or even paralysis. 1: True. 2: False.

False. Explanation: Nematocysts produce toxins that, when touched, can produce symptoms ranging from a mild rash or sting to anaphylactic shock or even paralysis.

We measure waves by their height and weight. 1: True. 2: False.

False. Explanation: We measure waves by their height and length.

Your body loses the greatest amount of heat through the: 1: Head. 2: Feet. 3: Hands. 4: None of the above.

Head.

Which of the following is/are true? 1: If caught in a rip current, swim directly towards shore, using the most powerful kick possible. 2: If caught in a rip current, swim perpendicular to shore, until you are completely out of the rip current, then swim in towards shore. 3: If caught in a rip current, swim parallel to shore, until you are completely out of the rip current, then swim in towards shore. 4: Don't fight the rip current; relax and let it carry you closer to shore.

If caught in a rip current, swim parallel to shore, until you are completely out of the rip current, then swim in towards shore.

Which 'if any' of the following are true? 1: Aquatic animals present a greater risk to divers than any other factor. 2: Most aquatic animal bites result from an animal's defensive response to a perceived threat or, on rare occasions, from a case of mistaken identify. 3: Because they are perceived as more aggressive, men are more likely to be the victim of an aquatic animal attack than women are. 4: None of the above.

Most aquatic animal bites result from an animal's defensive response to a perceived threat or, on rare occasions, from a case of mistaken identify.

Which of the following best describes the formation of surf? 1: Waves energy, rebounding from its impact with shore, crashes into oncoming waves, causing them to break. 2: Entering shallow water forces wave energy upward, making the wave crest unstable and causing it to break. 3: A wave encountering shallow water begins to slow at its bottom, while the top of the wave continues at its previous speed. This causes the wave to break. 4: As waves enter shallow water, the distance between wave crests (wave length) shortens, increasing the tendency to break.

Only the third answer (A wave encountering shallow water begins to slow at it bottom, while the top of the wave continues at its previous speed; this causes the wave to break) is correct.

A mask must cover the nose: 1: To prevent water from entering. 2: To ensure the best possible fit. 3: So that you can keep the pressure inside the mask equal to the pressure outside. 4: Both the first and second answers are correct.

So that you can keep the pressure inside the mask equal to the pressure outside.

Surge: 1: Occurs when waves force water between facing rock ledges. 2: Is the back-and-forth movement of water caused by waves passing over head. 3: Is the backwash of water from waves breaking on shore. 4: None of the above.

Surge is the back-and-forth movement of water caused by waves passing over head.

When water stratifies itself into layers, according to temperature, the boundary between layers is known as a(n): 1: Halocline. 2: Ichtyocline. 3: Thermodyne. 4: Thermocline.

Thermocline.

Depending on circumstances, there are times when divers may wish to be positively, negatively or neutrally buoyant. 1: True. 2: False.

True.

The sun warming water near the equator, coupled with the earth's rotation, is the primary cause of permanent ocean currents. 1: True. 2: False.

True.

Which of the following is/are true? 1: Water conducts heat away from your body ten times faster than air does. 2: Water conducts heat away from your body 25 times faster than air does. 3: Fresh water conducts heat away from your body faster than salt water does. 4: Salt water conducts heat away from your body faster than fresh water does.

Water conducts heat away from your body 25 times faster than air does.

Which of the following statements is not true? 1: Wet suits work by surrounding your body with a low-density material (neoprene) foam, that retards heat loss through radiation. 2: To work, a wet suit must fit snugly to reduce the amount of cold water that circulates through the suit. 3: Wet suits are unnecessary in water warmer than 25 °C/77 °F. 4: Dive skins help protect you from scrapes, abrasion and sunburn; however, they offer little in the way of insulation.

Wet suits are unnecessary in water warmer than 25 °C/77 °F.

All of the following are true except: 1: You can help prevent mask squeeze by exhaling periodically into your mask during ascent. 2: Regular dental care and ensuring your teeth are free of gas spaces can help prevent tooth squeeze. 3: If you experience a reverse block, descend to a point where the pain subsides, then ascend slowly while wiggling your jaw and swallowing. Repeat this process as needed until you can ascend without pain or discomfort. 4: The danger in taking decongestants is that they may wear off during a dive and have other possible side effects.

You can help prevent mask squeeze by exhaling periodically into your mask during ascent.