Chapter 5: Diving Physics
SSI Divecon course dead scientist chapter
Questions and Answers
- 1.
Water is denser than air.
- A.
True
- B.
False
Correct Answer
A. TrueExplanation
Water is denser than air because the particles in water are packed more closely together compared to the particles in air. This means that water has a higher mass per unit volume, resulting in a higher density. The density of water is approximately 1000 kg/m³, while the density of air is about 1.2 kg/m³. Therefore, water sinks in air and objects float in water because they are less dense than water.Rate this question:
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- 2.
A cubic foot of salt water weighs ___ pounds
Correct Answer
64Explanation
A cubic foot of salt water weighs 64 pounds because salt water has a density of 64 pounds per cubic foot. Density is the measure of mass per unit volume, so in this case, it means that for every cubic foot of salt water, it weighs 64 pounds.Rate this question:
- 3.
A cubic foot of fresh water weighs ___ pounds
Correct Answer
62.4Explanation
The weight of water is measured in pounds per cubic foot. The given answer, 62.4 pounds, is the correct weight for a cubic foot of fresh water.Rate this question:
- 4.
One atmosphere is ___ feet.
Correct Answer
33Explanation
One atmosphere is equal to 33 feet. This is a commonly used conversion in scuba diving, where each atmosphere of pressure is equivalent to an additional 33 feet of depth. Therefore, if someone is diving at a depth of 2 atmospheres, they would be 66 feet below the surface.Rate this question:
- 5.
____ is the relative hotness or coldness of a body or environment as measured on a standard scale, while ____ is defined as a form of energy that can be transmitted through solid or fluid medium by donduction, through fluid medium by convection, or through a space as infrared radiation.
- A.
Heat / temperature
- B.
Cold / sound
- C.
Temperature / heat
- D.
Energy / light
Correct Answer
C. Temperature / heatExplanation
Temperature is the relative hotness or coldness of a body or environment as measured on a standard scale, while heat is defined as a form of energy that can be transmitted through solid or fluid medium by conduction, through fluid medium by convection, or through a space as infrared radiation.Rate this question:
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- 6.
Water absorbs heat ____ times faster than air.
Correct Answer
25Explanation
Water absorbs heat 25 times faster than air because water has a higher heat capacity than air. Heat capacity is the amount of heat energy required to raise the temperature of a substance by a certain amount. Since water has a higher heat capacity, it can absorb more heat energy per unit mass compared to air. This means that water can absorb heat at a faster rate, making it more efficient at transferring heat compared to air.Rate this question:
- 7.
The "pulling away" of heat in cold water is a property of heat energy transmission known as:
- A.
Conduction
- B.
Convection
- C.
Radiation
- D.
Microwave
Correct Answer
A. ConductionExplanation
Conduction is the correct answer because it refers to the transfer of heat through direct contact between objects or substances. In the given scenario, the heat is being transferred from a warmer object to a colder object (the heat being pulled away from the cold water) through direct contact. This is a classic example of conduction, where heat energy is transmitted through the collision of particles within the substances involved.Rate this question:
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- 8.
Atmospheric pressure at One Atomsophere = _____ PSI.
Correct Answer
14.7Explanation
The atmospheric pressure at one atmosphere is equal to 14.7 PSI. This is because one atmosphere is defined as the average atmospheric pressure at sea level, which is equivalent to the pressure exerted by a column of mercury 760 millimeters high. This pressure is also equal to 14.7 pounds per square inch (PSI), which is the unit commonly used to measure pressure in the United States.Rate this question:
- 9.
The sum of atmospheric pressure and hydrostatic pressure is:
- A.
Gauge pressure
- B.
Absolute pressure
- C.
Sum pressure
- D.
Under pressure
- E.
Ambient pressure
Correct Answer
B. Absolute pressureExplanation
The sum of atmospheric pressure and hydrostatic pressure is known as absolute pressure. Atmospheric pressure is the pressure exerted by the weight of the atmosphere, while hydrostatic pressure is the pressure exerted by a fluid due to its weight. When these two pressures are combined, we get the absolute pressure, which represents the total pressure at a certain point. Gauge pressure, on the other hand, is the difference between the absolute pressure and atmospheric pressure. Sum pressure, under pressure, and ambient pressure are not accurate terms to describe this combination.Rate this question:
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- 10.
The pressur surrounding you, whether you are underwater or above water is:
- A.
Absolute pressure
- B.
Gauge pressure
- C.
Under pressure
- D.
Partial pressure
- E.
Ambient pressure
Correct Answer
E. Ambient pressureExplanation
Ambient pressure refers to the pressure exerted by the surrounding environment, whether it is underwater or above water. It is the total pressure experienced at a particular location, including atmospheric pressure and any additional pressure from the water or other sources. This term is used to describe the overall pressure conditions in a given situation, without specifying any specific reference point or measurement.Rate this question:
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- 11.
At a given pressure, the pressure of a single gas within a mixture of gases is.
- A.
Ambient pressure
- B.
Atmospheric pressure
- C.
Partial pressure
- D.
Absolute pressure
- E.
Gauge pressure
Correct Answer
C. Partial pressureExplanation
The pressure of a single gas within a mixture of gases is referred to as its partial pressure. This means that each gas in the mixture exerts its own pressure independent of the other gases present. The total pressure exerted by the mixture is the sum of the partial pressures of each gas. Therefore, in this context, the correct answer is "partial pressure."Rate this question:
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- 12.
The total pressure exerted by a mixture of gases is the sum of the pressures that would be exerted by each of the gases if it alone were present and occupied the total volume.
- A.
Archimedes' Principle
- B.
Dalton's Law
- C.
Boyle's Law
- D.
Henry's Law
- E.
Charles' Law
Correct Answer
B. Dalton's LawExplanation
Dalton's Law states that the total pressure exerted by a mixture of gases is equal to the sum of the partial pressures exerted by each individual gas in the mixture. This means that if each gas in the mixture occupied the total volume alone, it would exert a certain pressure. When combined, the total pressure exerted by the mixture is the sum of these individual pressures. Dalton's Law is based on the assumption that the gases in the mixture do not interact with each other.Rate this question:
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- 13.
What is the partial pressure of nitrogen at sea level? ____ PSI
Correct Answer
11.48Explanation
Nitrogen is 78.08% of air. Pressure at sea level is 14.7 PSI. Multiply .7808 * 14.7 to get 11.48.Rate this question:
- 14.
For any gas at a constant temperature, the volume will vary inversely with the absolute pressure while the density will vary directly with the absolute pressure. This is:
- A.
Dalton's Law
- B.
Boyle's Law
- C.
Archimedes' Principle
- D.
Charles' Law
- E.
Henry's Law
Correct Answer
B. Boyle's LawExplanation
Boyle's Law states that for any gas at a constant temperature, the volume of the gas is inversely proportional to the absolute pressure. This means that as the pressure increases, the volume of the gas decreases, and vice versa. This relationship holds true as long as the temperature remains constant. The statement also mentions that the density of the gas varies directly with the absolute pressure, meaning that as the pressure increases, the density of the gas also increases. However, this is not a specific law and is not attributed to any particular scientist or principle.Rate this question:
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- 15.
When pressure increases, volume of the gas ______. When pressure decreases, volume of a gas ______.
- A.
Decreases / increases
- B.
Increases / decreases
Correct Answer
A. Decreases / increasesExplanation
When pressure increases, the volume of the gas decreases. This is because an increase in pressure causes the gas molecules to move closer together, resulting in a decrease in volume. Conversely, when pressure decreases, the volume of a gas increases. This is because a decrease in pressure allows the gas molecules to spread out and occupy a larger space, leading to an increase in volume.Rate this question:
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- 16.
A gas is using 120 cubic feet at the surface. What volume will it be at 66 feet? ____ cubic feet
Correct Answer
40Explanation
As the question mentions that the gas is using 120 cubic feet at the surface, it implies that the volume of the gas is decreasing as it goes deeper. Therefore, when the gas reaches a depth of 66 feet, its volume would have decreased to 40 cubic feet.Rate this question:
- 17.
For any gas at a constant pressure, the volume of the gas will vary directly with the absolute temperature. For any gas at a constant volume, the presure of the gas will vary directly with the absolute temperature. This is:
- A.
Henry's Law
- B.
Archimedes' Principle
- C.
Boyle's Law
- D.
Charles' Law
- E.
Dalton's Law
Correct Answer
D. Charles' LawExplanation
Charles' Law states that for any gas at a constant pressure, the volume of the gas will vary directly with the absolute temperature. This means that as the temperature of a gas increases, its volume will also increase, and vice versa. This relationship is expressed mathematically as V1/T1 = V2/T2, where V1 and V2 are the initial and final volumes of the gas, and T1 and T2 are the initial and final temperatures in Kelvin. This law is named after Jacques Charles, a French physicist who first formulated it in the late 18th century.Rate this question:
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- 18.
The amount of any given gas that will dissolve in a liquid at a given temperature is a function of the partial pressure of that gas in contact with the liquid and the solubility coefficient of the gas in the particular liquid. This is:
- A.
Charles' Law
- B.
Boyle's Law
- C.
Dalton's Law
- D.
Henry's Law
- E.
Archimede's Principle
Correct Answer
D. Henry's LawExplanation
Henry's Law states that the amount of a gas dissolved in a liquid is directly proportional to the partial pressure of that gas in contact with the liquid. This means that as the partial pressure of the gas increases, more of it will dissolve in the liquid. The solubility coefficient of the gas in the specific liquid also plays a role in determining how much gas will dissolve. Therefore, Henry's Law is the correct answer as it accurately describes the relationship between gas solubility and partial pressure.Rate this question:
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- 19.
A body immersed in liquid, either wholly or partially, is buoyed up by a force equal to the weight of the liquid displaced by the body. This is:
- A.
Archimede's Principle
- B.
Boyle's Law
- C.
Charles' Law
- D.
Dalton's Law
- E.
Henry's Law
Correct Answer
A. Archimede's PrincipleExplanation
Archimedes' Principle states that when a body is immersed in a liquid, it experiences an upward buoyant force equal to the weight of the liquid it displaces. This principle explains why objects float or sink in liquids. The buoyant force helps to counteract the weight of the body, making it feel lighter. This principle is important in understanding the behavior of objects in fluids, such as ships floating in water or balloons floating in the air.Rate this question:
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- 20.
You will be less buoyant in salt water than fresh.
- A.
True
- B.
False
Correct Answer
B. FalseExplanation
The statement is true. Saltwater is denser than freshwater, which means that objects will be more buoyant in saltwater compared to freshwater. This is why it is easier to float in the ocean compared to a freshwater lake or pool. So, the correct answer should be "true".Rate this question:
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- 21.
_____, which is the bending of light waves, results when light waves pass through mediums of different densities, and changing speed.
Correct Answer
RefractionExplanation
Refraction is the correct answer because it is the phenomenon that occurs when light waves pass through mediums of different densities, causing the light waves to change direction and speed. This bending of light waves is a result of the change in the medium's optical density, which causes the light to deviate from its original path. Refraction is commonly observed when light passes through materials such as water or glass, where the speed of light is different than in air.Rate this question:
- 22.
Objects appear ___% closer underwater.
Correct Answer
25Explanation
When objects are viewed underwater, they appear closer than they actually are. This is due to the refraction of light as it passes from water to air, which causes the light rays to bend. As a result, the apparent distance between the observer and the object is reduced, making the object appear closer. In this case, the answer of 25% indicates that objects underwater appear 25% closer than they would if viewed in air.Rate this question:
- 23.
Objects appear ___% larger underwater.
Correct Answer
33Explanation
When an object is submerged in water, it appears larger due to the phenomenon of refraction. Refraction occurs because light travels at different speeds in different mediums, such as air and water. When light enters water from air, it slows down and changes direction, causing the object to appear larger than it actually is. The degree of enlargement depends on the refractive index of water, which is approximately 1.33. Therefore, objects appear approximately 33% larger underwater.Rate this question:
- 24.
What color disappears first underater?
- A.
Yellow
- B.
Green
- C.
Red
- D.
Orange
Correct Answer
C. RedExplanation
When light passes through water, it gets absorbed by the water molecules. The absorption spectrum of water shows that it absorbs light in the red part of the spectrum more strongly than other colors. This means that red light is more likely to be absorbed and scattered by water molecules, causing it to disappear or be less visible compared to other colors. Therefore, red color disappears first underwater.Rate this question:
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- 25.
Sound travels ___ times faters through water than air.
Correct Answer
4
fourExplanation
Sound travels four times faster through water than air. This is because the speed of sound is dependent on the medium it travels through. In general, sound travels faster in denser mediums, such as water, compared to less dense mediums like air. Water is about 800 times denser than air, which allows sound waves to propagate more quickly through it. Therefore, the speed of sound in water is approximately four times faster than in air.Rate this question:
- 26.
Changes in pressure will alter the volume of a gas.
- A.
True
- B.
False
Correct Answer
A. TrueExplanation
Changes in pressure will alter the volume of a gas because according to Boyle's law, there is an inverse relationship between pressure and volume. When the pressure on a gas increases, the volume decreases, and vice versa. This is because an increase in pressure compresses the gas particles closer together, reducing the overall volume that they occupy. On the other hand, a decrease in pressure allows the gas particles to expand and occupy a larger volume. Therefore, it can be concluded that changes in pressure do indeed affect the volume of a gas.Rate this question:
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- 27.
Pressure will force a gas into solution.
- A.
True
- B.
False
Correct Answer
A. TrueExplanation
When pressure is applied to a gas, the gas molecules are compressed and take up less space. As a result, the gas molecules come closer together and have a higher chance of colliding with the solvent molecules. This increased collision rate allows the gas molecules to dissolve more easily into the solvent, leading to the gas being forced into solution. Therefore, the statement "Pressure will force a gas into solution" is true.Rate this question:
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