SDI Final Exam questions with complete solutions, Study Guides, Projects, Research of Physics

Download SDI Final Exam questions with complete solutions and more Study Guides, Projects, Research Physics in PDF only on Docsity! SDI Final Exam 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.correct answerCloser and larger than they do on land. 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.correct answerAll of the above. 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.correct answerBoth the second and the third answer are correct. 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.correct answerWater conducts heat away from your body 25 times faster than air does. 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.correct answerThermocline. 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.correct answerAll of the above. 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.correct answerTrue. 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.correct answerIf caught in a rip current, swim parallel to shore, until you are completely out of the rip current, then swim in towards shore. We measure waves by their height and weight. 1: True. 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.correct answerYou can help prevent mask squeeze by exhaling periodically into your mask during 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.correct answerExhaling. 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.correct answerAll 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.correct answerAll of the above. 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.correct answerAscend to a depth at which the symptoms disappear. 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.correct answerEnd the dive and make a normal, slow ascent. 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.correct answerSo that you can keep the pressure inside the mask equal to the pressure outside. 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.correct answerBoth 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). To help prevent mildew, store equipment in a sealed container before it dries. 1: True 2: Falsecorrect answerFalse 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.correct answerWet suits are unnecessary in water warmer than 25 °C/77 °F. Your body loses the greatest amount of heat through the: 1: Head. 2: Feet. 3: Hands. 4: None of the above.correct answerHead. 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 answerCorrect 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. 3: Keep at least one second stage purge button depressed. 4: None of the above.correct answerCorrect 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. 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 answerCorrect 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. 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 answerCorrect 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. 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 answerCorrect Answer: Is chiefly a small-boat entry. Explanation: The backward roll is chiefly a small-boat entry. 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 correctcorrect answerCorrect 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. 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 answerCorrect 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 answerCorrect 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. 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, Blastcorrect answerCorrect 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. 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. 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 answerCorrect 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. 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 answerCorrect 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. 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 answerCorrect 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. 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 answerCorrect 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 answerCorrect 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. Diving safety begins with _______ ________ and _______ _______. 1: environmental awareness, self awareness 2: personal awareness, buddy dependence 3: environmental awareness, self sufficiency 4: personal awareness, self sufficiencycorrect answerCorrect Answer: personal awareness, self sufficiency Explanation: Diving safety begins with personal awareness and self sufficiency. 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 answerCorrect 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 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 answerCorrect Answer: All of the above. Explanation: All of the supplied answers are things buddies should agree upon prior to the dive. Explanation: If you cannot reunite with a missing buddy, seek assistance. Leave underwater searches to trained professionals. 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 answerCorrect Answer: A change in equilibrium in the middle ear. Explanation: Seasickness is caused by a change in equilibrium in the middle ear. 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 answerCorrect 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. 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 answerCorrect 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).