SDI Scuba Certification Exam 2024 Questions with Correct Detailed Solutions || Graded A+

SDI Scuba Certification Exam 2024 Questions with Correct Detailed Solutions || Graded A+ Buoyancy is - ANSWER when fluid pushes up on an object immersed in it. Archimedes' Principle states: - ANSWER "An object floating or immersed in a liquid will be buoyed up by a force equal to the weight of the volume of the liquid displaced." The denser the liquid, the higher a given object will float, and the heavier the liquid, the greater the buoyancy. Positive buoyancy: - ANSWER An object that weighs less than the weight of the liquid it displaces will float. Negative buoyancy: - ANSWER An object that weighs more than the weight of the liquid it displaces will sink. Neutral buoyancy: - ANSWER An object that weighs equal to the weight of the liquid it displaces will remain neutral, neither sinking nor floating. buoyancy system has two main parts: - ANSWER the Buoyancy Compensator (BC) and the weight system. Neutral buoyancy allows you to - ANSWER maneuver effortlessly and consume less air. Suspended in liquid space you are neither descending nor ascending. BCs are equipped with - ANSWER an inflator for orally inflating and deflating the BC. You can also inflate your BC with a power inflator attached to the first stage by pressing a button to introduce air into your BC. As well, you can deflate your BC with a pull dump valve. 14 steps to assembling your equipment in the correct sequence: - ANSWER 1. Pre-soak your BC strap to prevent the cylinder from becoming loose underwater. 2. Face the cylinder valve away from you. 3. Place your BC to the proper height of the cylinder by using the height adjustment strap (if available). 4. Secure your BC to the cylinder. 5. Check and inspect the cylinder O-ring or DIN fitting O-ring for cuts. 6. Standing behind the cylinder, position your Delivery System with the primary regulator over the right side and the alternate regulator and Information System on the left side and gently tighten. 7. Before turning on the breathing gas, check the primary regulator and alternate by inhaling gently — you should not be able to breathe. 8. Attach the power inflator hose to your BC. 9. Face your Information System down and away from you and close to the cylinder. 10. Turn the breathing gas on slowly all the way and then turn back a half-turn. 11. Inflate your BC fully, check the function of pressure relief and dump valves, leave your BC fully inflated and monitor for possible leakage and release air after successful leak test. 12. Check the performance of your regulators and the quality of breathing gas by pressing the purge valve. Clean breathing gas is colorless, odorless, and make sure they are working properly. 13. Once complete, place your Delivery and Information System inside your BC and secure it by laying the unit down. 14.For disassembling, simply reverse the order to take apart. The only difference is turning the breathing gas off. Once the breathing gas is off, it is necessary to purge all breathing gas from the Delivery System before removing it from the cylinder. Simplified- 1. Place the BC on the Cylinder2. Attach the Delivery System to the Cylinder3. Attach the Power Inflator Hose to the BC4. Turn the Breathing Gas on and test the Second Stage Regulator Three Basic Rules to Scuba Diving - ANSWER The First Rule of Scuba: Breathe continuously! The Second Rule of Scuba: Ascend slowly and maintain control! The Third Rule of Scuba: Never dive alone or beyond your level of training! During normal diving activities, divers should never exceed an ascent rate of __ feet per minute. - ANSWER 30 ft Your lungs are made up of - ANSWER approximately 300 million alveoli Dalton's Law - ANSWER the total pressure of a mixture of gases equals the sum of the partial pressures. Henry's Law states - ANSWER the amount of gas that will dissolve into a liquid is directly proportional to the partial pressure of the gas. Diving subsystems - ANSWER snorkeling exposure delivery information buoyancy accessory 1 atmosphere is (_______) psi or (_______) bar - ANSWER about 15 or 1 pressure increases by 1 atmosphere every (_____) feet - ANSWER 33 (in seawater) 34 (fresh water) absolute pressure - ANSWER total pressure on an object gauge pressure - ANSWER absolute pressure-1 atmosphere pressure shown on gauges represents extra pressure added underwater (there is 1 atmosphere already at the surface) boyle's law - ANSWER at constant temperature, volume and pressure are inversely related pressure increases, volume decreases pressure decreases, volume increases ear injury can occur with a difference of as little as (_____) - ANSWER 0.5 psi or 10 feet signs of sinus squeeze - ANSWER sharp pain or wedging feeling above the eyes prevent mask squeeze by - ANSWER exhaling into your mask every few feet ear equalization technique - ANSWER swallow rotate jaw vasalva descent posture - ANSWER vertical with feet up avoid reverse squeezes by - ANSWER ascend slowly stop and allow trapped air to escape stop if you feel pain above the eyes (reverse sinus squeeze) mask clearing - ANSWER tilt head back press on top edge of mask blow air out through nose vision changes underwater; objects appear - ANSWER 33% closer 25% larger this is due to refraction colors underwater - ANSWER warm colors disappear as you go deeper this is due to absorption diffusion - ANSWER light is softer, less harsh, and less intense underwater thermocline - ANSWER change in temperature as depth increases colder water sinks and is therefore in the deeper layers conduction - ANSWER movement of heat between objects that are touching e.g. you body giving off heat to the surroundings convection - ANSWER cyclic movement of heat warm molecules move away from the body and are replaced by cold ones heat loss is (_____) times faster in water - ANSWER 25-30 air use at depth - ANSWER increases 2 atmospheres absolute/33 feet, 2x air use 5 atmospheres absolute/132 feet, 5x air use proper attitude - ANSWER 15 degrees horizontal but slightly tilted upwards air ratios - ANSWER 21% oxygen 78% nitrogen 1% trace other gases buoyancy types - ANSWER neutral positive negative rules of scuba - ANSWER breathe continuously ascend slowly, maintain control don't dive alone, dive within your skills how much pressure can lungs endure? - ANSWER overpressure of 2 psi this is about 4 feet easiest way to avoid overexpansion injuries - ANSWER breathe slowly and continuously arterial gas embolism (AGE) - ANSWER most serious air bubbles from burst alveoli reach brain pneumothorax - ANSWER air bubbles move into area around lung can collapse lung and make breathing difficult subcutaneous emphasema - ANSWER air bubbles move up by the collar bone and neck mediastinal emphasema - ANSWER air moves into area around heart this can stop the heart and be very serious signs of overaxpansion injuries - ANSWER there may be no signs! follow the first rule to avoid these injuries if a diver becomes unconscious during or 4-6 minutes after a dive, it might be an AGE. This requires a recompression chamber. other symptoms of AGE Unconsciousness or coma Respiratory and circulatory distress and/or failure Loss of small motor and gross motor control and paralysis Headache Vertigo Visual, auditory, and speech abnormalities treatment of overexpansion injuries - ANSWER Treat for shock. Administer oxygen, if qualified. Stand by to administer cardio-pulmonary resuscitation (CPR), if qualified. Obtain proper medical aid (emergency room and a recompression chamber) as quickly as possible decompression sickness - ANSWER aka caissons disease the body absorbs nitrogen under pressure as pressure decreases, nitrogen can come out of solution must ascend slowly to allow desaturation a too fast ascent can cause supersaturation which will make the nitrogen come out of solution and form bubbles signs of decompression sickness - ANSWER deep and persistent pain, especially in the joints itchy rash, visual disturbances, motor paralysis, weakness, loss of manual dexterity, vertigo, numbness, respiratory distress, headache, unconsciousness, loss of memory, nausea seek medical treatment if you have any of these symptoms treating decompression sickness - ANSWER call EMS and follow their instructions treat for shock, monitor vitals, administer oxygen (if qualified) administer CPR (if qualified) recompression may be required ascent rate - ANSWER 30 feet per minute ascent procedure - ANSWER look up hold inflator hose up above your head safety stop - ANSWER 3-5 minutes at 15 feet during ascent flying - ANSWER don't fly for 24 hours after diving nitrogen narcosis - ANSWER nitrogen at high partial pressure can dull nerves, producing a narcotic effect this can be dangerous since it affects decision making and motor skills signs: Light headedness, numbness and increasing selfconfidence/euphoria Unusual behavior, Loss of dexterity Dizziness Abnormal vision and hearing Inability to reason or follow a dive plan Carelessness about personal well-being Short-term memory loss and losing track of time treatment: ascend to a shallower depth oxygen toxicity - ANSWER A high partial pressure of oxygen can be poisonous; don't go above a pp of 1.4 ata signs: ConVENTID: Convulsions, Visual problems, Ear disorder, Nausea, Twitching, Irritability and Dizziness ascend if you have symptoms carbon dioxide buildup - ANSWER aka hypercapnia signs: Distress and anxiety Headache, caused by dilation of capillaries in the brain Possible confusion and irrational behavior Drowsiness and unconsciousness treatment/prevention: don't dive below 100 feet don't overexert yourself carbon monoxide poisoning - ANSWER can happen if gas is contaminated signs can be delayed at pressure signs: Red lips and nail beds Headache Dizziness Nausea Weakness Uncoordinated movements Confusion and inability to reason Unconsciousness Respiratory failure treatment: Move the victim into fresh, uncontaminated gas. Administer oxygen, if qualified. Pure oxygen hastens the elimination of carbon monoxide from the blood. Be prepared to administer CPR if necessary and if qualified. Contact local emergency services and/or arrange immediate transport to an emergency medical center recreational diving limit - ANSWER 100 feet depth - ANSWER lowest depth reached during dive bottom time - ANSWER time elapsed from start of descent to start of ascent total dive time - ANSWER time from start of descent until you reach the surface again