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Scuba AFS 270 SDI Midterm Exam Updated
(1) You can help prevent mask squeeze by exhaling periodically into your mask during ascent. - ANSWER-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. (2) Ascend to the point where you can comfortably equalize, and only then continue your descent. - ANSWER-If you feel pain or discomfort during descent: 1: Stop, hold in place and equalize forcefully until your ears clear. 2: Ascend to the point where you can comfortably equalize, and only then continue your descent. 3: Abort the dive and consult a physician. 4: Note the depth at which the pain occurred and conduct your safety stop there at the end of the dive. (2) Breathe continuously; never hold your breath. - ANSWER-The single most important rule of scuba diving is: 1: Equalize early and often. 2: Breathe continuously; never hold your breath. 3: Never descend head first. 4: None of the above. (2) Hydrostatically tested and visually inspected at intervals determined by local laws and regulations, or prevailing standards of practice. - ANSWER-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. (2) The elevated partial pressure of nitrogen divers experience at depth. - ANSWER- The chief cause of nitrogen narcosis is: 1: Diving past 40 m/132 ft. 2: The elevated partial pressure of nitrogen divers experience at depth. 3: The combination of carbon dioxide and nitrogen at depth. 4: None of the above.
(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. - ANSWER- 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. (3) Air permitting, make the decompression stop indicated by your dive computer. Afterward, monitor for signs and symptoms of decompression sickness. - ANSWER- Should you accidentally exceed your dive computer's no-decompression limit. 1: Stop for two minutes at 6 m/20 ft and five minutes at 3 m/10 ft. 2: Ascend immediately, begin breathing pure oxygen and contact the Divers Alert Network (DAN). 3: Air permitting, make the decompression stop indicated by your dive computer. Afterward, monitor for signs and symptoms of decompression sickness. 4: None of the above. (3) Avoid drinking fluids prior to the dive. - ANSWER-All of the following can help prevent decompression sickness (DCS) except: 1: Make a safety stop of between three and five minutes at a depth of 3-6 m/10-20 ft. 2: Remain well within your dive computer's no-decompression limit. 3: Avoid drinking fluids prior to the dive. 4: Ascend no faster than the rate allowed by the dive computer (3) Create an air space in front of the eyes, enabling them to focus. - ANSWER-The primary function of a mask is to: 1: Magnify the appearance of objects under water. 2: Cover the nose, to prevent water from entering. 3: Create an air space in front of the eyes, enabling them to focus. 4: None of the above. (3) Take several deep breaths from your regulator while watching your SPG for changes in pressure. - ANSWER-After your buddy checks to see that your air is turned all the way on: 1: You are ready to enter. 2: Reach back and double check it yourself. 3: Take several deep breaths from your regulator while watching your SPG for changes in pressure. 4: None of the above.
1: Self rescue. - ANSWER-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. 1: Tow him on the surface. - ANSWER-If your buddy is unable to swim on his own, you can: 1: Tow him on the surface. 2: Tow him under water. 3: Both the first and second answers are correct. 4: None of the above. 1: True. - ANSWER-Without proper training, all you may accomplish by searching for a missing buddy on your own is to put yourself at risk. 1: True. 2: False. 1: Twice. - ANSWER-The volume of gas in a flexible container at a depth of 10 m/33 ft will expand to ______ its original volume if taken to the surface. 1: Twice. 2: Three times. 3: Four times. 4: None of the above. 1/one - ANSWER-If you become separated from your buddy, search for no more than ________ minute(s), then surface. 2 (Ascend to a depth at which the symptoms disappear.) - ANSWER-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. 2 (exhaust valve highest point of air cell) - ANSWER-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. 2 (Nitrox and Trimix) - ANSWER-Additional features common to many dive computers include all of the following except:
1: The ability to display dive log data and to upload that data to a laptop or desktop computer. 2: The ability to monitor a diver's exposure to air, Nitrox and Trimix. 3: The ability to project no-decompression limits for upcoming dives. 4: Bar graphs that provide a visual representation of a diver's exposure to nitrogen and other gasses. 2 (Slow down and switch to a different style of kick.) - ANSWER-Which of the following is the most effective means of preventing a leg cramp from returning? 1: Remove the fin from the affected leg and kick using just the remaining fin. 2: Slow down and switch to a different style of kick. 3: Swim with just your hands. 4: 1 or 3, but not 2 2 (soak the band) - ANSWER-If possible, before attaching your BC to your scuba cylinder, you should: 1: Inflate it completely. 2: Soak the cam band (tank band) in water. 3: Attach the regulator to the cylinder first. 4: Connect the BC low-pressure inflator hose to the BC. 2 (Surge is the back-and-forth movement of water caused by waves passing over head.) - ANSWER-Which of the following is/are true? 1: Surge is the backwash of water from waves breaking on shore. 2: Surge is the back-and-forth movement of water caused by waves passing over head. 3: Surge occurs when waves force water between facing rock ledges. 4: None of the above. 2 (warn boaters) - ANSWER-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. 2 (Water conducts heat away from your body 25 times faster than air does) - ANSWER- 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. 2 (You and your buddy should both follow the most conservative of the two dive computers.) - ANSWER-Your dive computer indicates you need to make a mandatory decompression stop. You buddy's dive computer does not. You should: 1: Follow your buddy's dive computer and have yours repaired.
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. 2: More conservative - ANSWER-On most repetitive dives, your computer will provide _______ no-decompression limits than on single dives. 1: Less conservative 2: More conservative 3: Significantly greater 4: None of the above 2: Nematocysts. - ANSWER-Some aquatic animals possess stinging cells. These cells are called: 1: Hypothocysts. 2: Nematocysts. 3: Psoriacysts. 4: None of the above. 2: Nematocysts. - ANSWER-Some aquatic animals possess stinging cells. These cells are called: 1: Hypothocysts. 2: Nematocysts. 3: Psoriacysts. 4: None of the above. 2: Partially inflated. - ANSWER-In general, you want to enter the water with your BC: 1: Deflated. 2: Partially inflated. 3: Fully inflated. 4: Both the first and third answers are acceptable; the second answer is not. 2: Preventing problems while at the same time having a planned response for any emergency. - ANSWER-Risk management is defined as: 1: Eliminating any possibility of a diving accident. 2: Preventing problems while at the same time having a planned response for any emergency. 3: Having the right kind of insurance. 4: Both the first and third answers are correct. 2: Reduce high-pressure gas in the scuba cylinder to ambient (surrounding) pressure. - ANSWER-The primary function of a scuba regulator is to: 1: Reduce high-pressure gas in the scuba cylinder to a more breathable intermediate pressure. 2: Reduce high-pressure gas in the scuba cylinder to ambient (surrounding) pressure. 3: Provide a diver with a continuous flow of oxygenated air. 4: None of the above.
2: Roll into it. - ANSWER-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. 2: Soak the cam band (tank band) in water. - ANSWER-If possible, before attaching your BC to your scuba cylinder, you should: 1: Inflate it completely. 2: Soak the cam band (tank band) in water. 3: Attach the regulator to the cylinder first. 4: Connect the BC low-pressure inflator hose to the BC. 2: Stop, relax and breathe deeply. - ANSWER-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. 2: Surge is the back-and-forth movement of water caused by waves passing over head.
- ANSWER-Which of the following is/are true? 1: Surge is the backwash of water from waves breaking on shore. 2: Surge is the back-and-forth movement of water caused by waves passing over head. 3: Surge occurs when waves force water between facing rock ledges. 4: None of the above. 2: Take it off and put it on like a jacket. - ANSWER-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. 2: The exhaust valve you will be using must be the highest point on the air cell. - ANSWER-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. 2: Wipe it with a clean, dry towel or cloth. - ANSWER-The preferred way to remove moisture from a dust cap prior to putting it back in place is to: 1: Shake it vigorously. 2: Wipe it with a clean, dry towel or cloth.
3 (expend energy) - ANSWER-Using your arms to swim under water: 1: Dramatically increases your overall speed and efficiency. 2: Somewhat increases your overall speed and efficiency. 3: Causes you to expend energy needlessly. 4: None of the above. 3 (The availability of regular, professional maintenance.) - ANSWER-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. 3 (The decreasing pressure may allow your regulator to function, even if it could not do so at depth.) - ANSWER-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. 3: At safety-stop depth, at the end of the dive. - ANSWER-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. 3: Avoid drinking fluids prior to the dive. - ANSWER-All of the following can help prevent decompression sickness (DCS) except: 1: Make a safety stop of between three and five minutes at a depth of 3-6 m/10-20 ft. 2: Remain well within your dive computer's no-decompression limit. 3: Avoid drinking fluids prior to the dive. 4: Ascend no faster than the rate allowed by the dive computer 3: Dead air spaces. - ANSWER-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.
3: Get the diver back in the water and repeat any missed or omitted decompression. - ANSWER-First aid for suspected decompression sickness may include all of the following except: 1: Activate the Emergency Medical Service (EMS) system and contact the Divers Alert Network (DAN). 2: Monitor the patient's vital signs. 3: Get the diver back in the water and repeat any missed or omitted decompression. 4: Administer pure oxygen. 3: Grasp the fin tip of the affected leg and pull towards you while straightening the leg. This stretches the calf muscle. - ANSWER-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. 3: Help you to find your way back to your starting point without having to surface to take a new heading. - ANSWER-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. 3: If the bottom of a wave moves faster than the top, the wave will break. - ANSWER- Which of the following is not true? 1: Entering shallow water causes the base of a wave to slow. 2: Entering shallow water forces wave energy upward, making the wave crest unstable and causing it to break. 3: If the bottom of a wave moves faster than the top, the wave will break. 4: Both the first and second answers are true. 3: Inhale cautiously, so that you can 'breathe past" any remaining water. - ANSWER- After exhaling to clear water from your second stage, you should: 1: Inhale deeply, as you will likely be out of breath. 2: Inhale partially, then press the purge button. 3: Inhale cautiously, so that you can 'breathe past" any remaining water. 4: None of the above. 3: Is chiefly a small-boat entry. - ANSWER-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.
2: Equipment. 3: Experience. 4: All of the above. 4 (all of the above masks) - ANSWER-Desirable mask features include: 1: Soft, silicone skirt. 2: Low internal volume. 3: Snug, comfortable fit. 4: All of the above. 4 (all of the above) - ANSWER-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. 4 (Any of the above.) - ANSWER-Which of the following may indicate that air in a scuba cylinder is contaminated and potentially toxic? 1: Color. 2: Odor. 3: Taste. 4: Any of the above. 4 (Both the first and second answers are correct; weight.) - ANSWER-Common weight systems include: 1: Weight belts. 2: BCs with integrated weight systems. 3: Cylinders with weights permanently affixed to the boot. 4: Both the first and second answers are correct. 4 (both the first and second answers are correct) - ANSWER-Which of the following statements are true? 1: Wave height is the distance from its highest point (crest) to its lowest point (trough). 2: Wave length is the distance from crest to crest. 3: Wave oscillation to calculated by multiplying the wave height times its length. 4: Both the first and second answers are correct. 4 (both the first and third answers are correct navigation) - ANSWER-Techniques commonly used to navigate under water include: 1: Natural navigation. 2: Computer navigation. 3: Compass navigation. 4: Both the first and third answers are correct.
4 (Both the first and third answers are correct.) - ANSWER-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. 4 (Both the second and third answers are correct.) - ANSWER-Treatment of DCS may involve: 1: In-water recompression. 2: Administration of pure oxygen. 3: Recompression in a hyperbaric chamber. 4: Both the second and third answers are correct. 4 (first and third, alt air and instrument) - ANSWER-What piece of equipment should never be allowed to dangle freely? 1: Alternate-air-source second stage. 2: BC power inflator. 3: Submersible pressure gauge or instrument console. 4: Both the first and third answers are correct. 4 (none of the above) - ANSWER-As you descend: 1: Colors will remain largely the same. 2: Blues and grays disappear quickly. 3: Dive lights have little effect on apparent color. 4: None of the above. 4: 20°C/68°F - ANSWER-Hoods become necessary any time water temperatures drop below: 1: 5°C/41°F 2: 10°C/50°F 3: 15°C/59°F 4: 20°C/68°F 4: All of the above. - ANSWER-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. 4: All of the above. - ANSWER-An additional type of squeeze divers may suffer is a: 1: Mask squeeze. 2: Tooth squeeze. 3: Reverse block.
4: Both the first and third answers are correct. - ANSWER-A regulator equipped with a conventional alternate-air-source second stage: 1: Is the among the most widely used and readily understood type of alternate air source. 2: Limits the receiver to using only the alternate-air-source second stage. 3: Allows the donor to give either second stage to an out-of-air diver. 4: Both the first and third answers are correct. 4: Both the first and third answers are correct. - ANSWER-In the event your computer fails, and you are not carrying a back-up computer: 1: End the dive and make a slow ascent and safety stop. 2: Stop for two minutes at 6 m/20 ft and five minutes at 3 m/10 ft. 3: Do not get back in the water for at least 24 hours. 4: Both the first and third answers are correct. 4: Both the first and third answers are correct. - ANSWER-Scuba cylinders must periodically undergo: 1: Hydrostatic testing. 2: Anticorrosive re-coating. 3: Visual inspections. 4: Both the first and third answers are correct. 4: Both the first and third answers are correct. - ANSWER-The types of fins commonly used by recreational scuba divers include: 1: Full-foot fins. 2: Detachable-blade fins. 3: Open-heel/adjustable fins. 4: Both the first and third answers are correct. 4: Both the first and third answers are correct. - ANSWER-What causes most aquatic animal bites? 1: An animal's defensive response to a perceived threat. 2: Sharks. 3: Mistaken identity. 4: Both the first and third answers are correct. 4: Both the first and third answers are correct. - ANSWER-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. 4: Both the second and third answers are correct. - ANSWER-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. 4: Both the second and third answers are correct. - ANSWER-The best type of boat entry: 1: Is a backward roll. 2: Is the one the crew recommends. 3: Is generally the easiest. 4: Both the second and third answers are correct. 4: Twenty-five times faster than air does. - ANSWER-Water conducts heat away from your body: 1: Twice as fast as air does. 2: Four times faster than air does. 3: Ten times faster than air does. 4: Twenty-five times faster than air does.
- Both the first and second answers are correct. - ANSWER-Should you become entangled under water: 1: Do not struggle in an effort to free yourself. 2: If you cannot easily untangle yourself, have your buddy do it for you. 3: Do not use a knife or cutting tool on the entanglement. 4: Both the first and second answers are correct.
- Both the first and third answers are correct. - ANSWER-A repetitive dive is any dive: 1: Made within 24 hours of a previous dive. 2: Made within 48 hours of a previous dive. 3: In which your computer indicates there is residual nitrogen left in your system from a prior dive. 4: Both the first and third answers are correct. A change in equilibrium in the middle ear. - ANSWER-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. abort, reason - ANSWER-Any diver can signal to ______ the dive for any ________.' 1: shorten, reason 2: continue, buddy 3: abort, reason 4: abort, buddy
3: Signal others under water by using it to bang on a cylinder. 4: Both the second and third answers are correct. closer and larger - ANSWER-objects underwater appear ___ and ___ than they do on land dust cap - ANSWER-If you will be rinsing your regulator after removing it from the cylinder, you must make sure that the ______ ______ is firmly in place. exhaling/blowing bubbles - ANSWER-Any time you cannot inhale while scuba diving (such as when a regulator is out of your mouth), you must be... false (contact lense) - ANSWER-T/F Contact lens wearers should not close their eyes when clearing a mask. false (it's actually nematocysts) - ANSWER-T/F Psoriacysts produce toxins that, when touched, can produce symptoms ranging from a mild rash or sting to anaphylactic shock or even paralysis. false (squeeze) - ANSWER-T/F Taking decongestants is a good way to reduce the risk of ear or sinus squeeze. False. - ANSWER-To help prevent mildew, store equipment in a sealed container before it dries. (TRUE OR FALSE) Head - ANSWER-Your body loses the greatest amount of heat through the: 1: Head. 2: Feet. 3: Hands. 4: None of the above. Lean towards your right and dip your right shoulder. - ANSWER-Key points in recovering a second stage using the sweep method include: 1: Using your left hand to push up on the bottom of your cylinder. 2: Lean towards your right and dip your right shoulder. 3: Lean towards your left and dip your left shoulder. 4: None of the above. None of the above - ANSWER-The type of kick most commonly used by recreational divers is the: 1: Frog kick. 2: Dolphin kick. 3: Bicycle kick. 4: None of the above.
personal awareness, self sufficiency - ANSWER-Diving safety begins with _______ ________ and _______ _______. plan, plan - ANSWER-____ your dive, dive your ___ pregnant - ANSWER-Divers who are or who could be ________ should not dive. Pushing in at the top corners. - ANSWER-When clearing a mask of water, you should form a seal by: 1: Pushing in at the bottom. 2: Pushing in at the top corners. 3: Pulling out slightly at the bottom. 4: None of the above. Surface, under water - ANSWER-If you and your buddy follow the same plan for dealing with buddy separation, you will end up meeting either on the _________ or ________ ___________. 1: Surface, dive boat 2: Shore, dive boat 3: Surface, under water 4: Boat, under water The weaker buddy. - ANSWER-Which member of the buddy team determines the pace for the dive? 1: It doesn't matter, so long as both buddies agree. 2: The stronger buddy. 3: The weaker buddy. 4: None of the above. thermocline - ANSWER-When water stratifies itself into layers, according to temperature, the boundary between layers is known as a(n): To be successful in maintaining neutral buoyancy, you must be: aware of changes in depth; and, anticipate the need to add or vent air from your BC by keeping a hand on the inflator. - ANSWER-Among the key points in using your BC to help maintain neutral buoyancy under water: 1: Add or remove air to or from your BC only in large bursts, until you develop a more intuitive feel for the process. 2: To be successful in maintaining neutral buoyancy, you must be: aware of changes in depth; and, anticipate the need to add or vent air from your BC by keeping a hand on the inflator. 3: Before you can achieve neutral buoyancy, you must first assume a fin-pivot position on the bottom. 4: None of the above. true - ANSWER-T/F
