2.
Which of the below is not a type of heat transfer?
Correct Answer
A. Expansion
Explanation
Expansion is not a type of heat transfer. Expansion refers to the increase in volume or size of a substance when it is heated. It is a physical property of matter and not a method of transferring heat from one object to another. Conduction, radiation, and convection are the three main types of heat transfer, where heat is transferred through direct contact, electromagnetic waves, and movement of fluids, respectively.
3.
The transfer of heat between materials that are in direct contact is called ?
Correct Answer
conduction
Explanation
Conduction is the transfer of heat between materials that are in direct contact with each other. It occurs when the molecules in a warmer object collide with the molecules in a cooler object, transferring energy and increasing the temperature of the cooler object. This process continues until both objects reach thermal equilibrium. Conduction is an important mechanism for heat transfer in solids, where the molecules are closely packed and can easily interact with each other.
4.
The first law of thermodynamics would tell you that you can't get more work out of a machine than the amount of energy that you put in.
Explanation
The first law of thermodynamics, also known as the law of conservation of energy, states that energy cannot be created or destroyed, only transferred or converted from one form to another. In the context of a machine, this means that the amount of work output cannot exceed the amount of energy input. Therefore, the statement that you cannot get more work out of a machine than the amount of energy you put in is true.
5.
The type of heat transfer that can take place through a vacuum is called ?
Correct Answer
radiation
Explanation
Radiation is the type of heat transfer that can take place through a vacuum. Unlike conduction and convection, which require a medium such as solids, liquids, or gases to transfer heat, radiation can occur in the absence of a medium. It involves the emission and absorption of electromagnetic waves, such as infrared radiation, which can travel through a vacuum. This is why the heat from the Sun can reach the Earth through the vacuum of space.
6.
In the equation:change in U = Q - W Q stands for ?
Correct Answer
heat
Explanation
In the given equation, "change in U = Q - W," Q represents heat. This equation is used to calculate the change in internal energy (U) of a system, where Q represents the heat added or removed from the system, and W represents the work done on or by the system. Therefore, the correct answer is heat.
7.
A form of heat transfer that occurs by currents in a fluid (gas or liquid) is ?
Correct Answer
convection
Explanation
Convection is a form of heat transfer that occurs through the movement of currents in a fluid, such as gas or liquid. When a fluid is heated, it becomes less dense and rises, while the cooler, denser fluid sinks. This creates a circular motion of the fluid, transferring heat from one place to another. Convection is responsible for various natural phenomena, such as the circulation of air in the atmosphere, ocean currents, and even the boiling of water.
8.
On the Fahrenheit scale, water boils at ? degrees.
Explanation
Water boils at 212 degrees Fahrenheit on the Fahrenheit scale. This is the correct answer because 212 degrees Fahrenheit is the boiling point of water on the Fahrenheit scale.
9.
A very poor conductor such as wood or styrofoam is known as an ? because they delay the transfer of heat.
Correct Answer
insulator
Explanation
An insulator is a material that does not conduct heat well and therefore delays the transfer of heat. Wood and styrofoam are examples of very poor conductors, or insulators, because they have a low thermal conductivity. Unlike metals or other good conductors, insulators do not allow heat to flow easily through them, making them effective at preventing the transfer of heat.
10.
The SI scale of temperature used in scientific research is the ? scale.
Correct Answer
Kelvin
Explanation
The SI scale of temperature used in scientific research is the Kelvin scale. The Kelvin scale is an absolute temperature scale where zero Kelvin represents absolute zero, the point at which all molecular motion ceases. It is commonly used in scientific experiments and calculations because it provides a more accurate and consistent measurement of temperature compared to other scales like Celsius or Fahrenheit.
11.
The second law of thermodynamics would back up this statement:Heat will never of itself flow from a cold object to a hot object.
Explanation
The second law of thermodynamics states that heat will never spontaneously flow from a colder object to a hotter object. This is because heat naturally flows from regions of higher temperature to regions of lower temperature. Therefore, the given statement aligns with the second law of thermodynamics and is true.
12.
The measure of the amount of disorder in a system is called ?
Correct Answer
entropy
Explanation
Entropy is a measure of the amount of disorder or randomness in a system. It quantifies the number of possible arrangements or states that a system can have. A system with high entropy has a high level of disorder, while a system with low entropy has a high level of order. Therefore, entropy is the correct answer for the measure of the amount of disorder in a system.
13.
The quantity that tells how hot or cold something is compared to a standard is ? and it is related to the average kinetic energy of a substance.
Correct Answer
temperature
Explanation
Temperature is the quantity that tells how hot or cold something is compared to a standard. It is related to the average kinetic energy of a substance. Temperature measures the intensity of heat present in an object or environment. It is a fundamental property of matter and is commonly measured using various scales such as Celsius, Fahrenheit, or Kelvin.
14.
The first law of thermodynamics is really just a restatement of the law of conservation of ?
Correct Answer
energy
Explanation
The first law of thermodynamics states that energy cannot be created or destroyed, only transferred or converted from one form to another. This is essentially a restatement of the law of conservation of energy, which states that the total energy in a closed system remains constant. Therefore, the correct answer is "energy" as it aligns with both the first law of thermodynamics and the law of conservation of energy.
15.
The second law of thermodynamics deals with what is most likely to happen (probability) instead of what has to happen.
Explanation
The second law of thermodynamics states that in any energy transfer or transformation, the total entropy of a closed system will always increase over time. This means that the system will tend towards a state of greater disorder or randomness. The law does not dictate what will happen in a specific situation, but rather describes the statistical probability of events occurring. Therefore, it deals with what is most likely to happen rather than what has to happen, making the statement "True" accurate.
16.
The second law of thermodynamics would back up this statement:
Whenever energy is transformed, some of the energy will degenerate to useless forms and is unavailable for doing the same work again.
Explanation
The second law of thermodynamics states that in any energy transformation, there is always a decrease in usable energy and an increase in unusable energy. This means that some of the energy will inevitably be lost or transformed into forms that cannot be used to do work again. Therefore, the statement that "Whenever energy is transformed, some of the energy will degenerate to useless forms and is unavailable for doing the same work again" is supported by the second law of thermodynamics.
17.
A thermometer comes to thermal equilibrium with whatever it is place in, therefore a thermometer actually registers its own temperature.
Explanation
A thermometer works by measuring the temperature of its surroundings. When it comes into contact with an object or a substance, it exchanges heat with it until both reach the same temperature, which is called thermal equilibrium. Therefore, a thermometer does register its own temperature because it is in thermal equilibrium with the environment it is placed in.
18.
On the Fahrenheit scale, water freezes at ? degrees.
Explanation
Water freezes at 32 degrees on the Fahrenheit scale. This is the freezing point of water, where it changes from a liquid to a solid state. The Fahrenheit scale is commonly used in the United States, and 32 degrees is the specific temperature at which water freezes in this scale.
19.
The third law of thermodynamics says that as the temperature of a substance approaches absolute zero, the entropy approaches zero.
Explanation
The third law of thermodynamics states that as the temperature of a substance approaches absolute zero, the entropy (measure of disorder) of the substance also approaches zero. This means that at absolute zero, the substance would have no disorder or randomness. This law is based on the observation that as a substance gets colder, its particles have less energy to move around and become more ordered. Therefore, the given answer "True" is correct.
20.
One can come infinitely close to absolute zero but cannot reach this limit.
Explanation
Absolute zero is the lowest possible temperature that can be reached, which is -273.15 degrees Celsius or 0 Kelvin. As an object approaches absolute zero, its temperature decreases but never actually reaches the absolute zero point. This is because reaching absolute zero would require removing all thermal energy from the object, which is practically impossible. Therefore, one can continuously get closer and closer to absolute zero but can never actually reach it.
21.
If a piece of aluminum is placed in contact with both a bathtub full of cool water and a cup of hot water, which way will heat flow?
Correct Answer
A. From the cup to the bathtub
Explanation
Heat will flow from the cup to the bathtub because heat always flows from a higher temperature to a lower temperature. The cup of hot water has a higher temperature than the bathtub full of cool water, so heat will transfer from the cup to the bathtub until both reach an equilibrium temperature.
22.
In this type of heat transfer, some of the particles making up the substance move from one region to another.
Correct Answer
A. Convection
Explanation
Convection is the correct answer because it involves the movement of particles within a substance. In convection, the particles transfer heat energy by physically moving from one region to another. This can occur in liquids and gases, where heated particles become less dense and rise, while cooler particles sink. This process creates a circular motion, allowing for the transfer of heat throughout the substance. Conduction, on the other hand, involves the transfer of heat through direct contact between particles, without any movement of the particles themselves.
23.
The first law of thermodynamics can be written several different ways, one of them is:change in U = Q - W U stands for ? ?
Correct Answer
internal energy
Explanation
The first law of thermodynamics states that the change in internal energy (U) of a system is equal to the heat (Q) added to the system minus the work (W) done by the system. In this equation, U represents the internal energy of the system, which is the sum of the kinetic and potential energies of its particles. Therefore, the correct answer is internal energy.
24.
Air is a good conductor.
Explanation
Air is a very poor conductor making it an insulator and any substance that traps air is a good insulator.
25.
The second law of thermodynamics would back up this statement:A barrel of pennies is dumped on the floor. The pennies could all come up heads but because there are many more ways for the pennies not to all come up heads, that is more likely to happen.
Explanation
The second law of thermodynamics states that in a closed system, the entropy (measure of disorder) tends to increase over time. In the case of the barrel of pennies being dumped on the floor, there are many more ways for the pennies to not all come up heads (disorder) compared to the specific arrangement of all pennies coming up heads (order). Therefore, it is more likely for the pennies to not all come up heads, which aligns with the second law of thermodynamics. Hence, the statement is true.
26.
In this type of heat transfer, energy moves but the actual particles making up the substance do not.
Correct Answer
A. Conduction
Explanation
Conduction is the correct answer because it is a type of heat transfer where energy is transferred from one particle to another through direct contact, without the actual particles themselves moving. In conduction, heat is conducted through a solid material or between two objects in direct contact.
27.
The temperature scale that assigns 0 degrees to the freezing point of water and 100 degrees to the boiling point of water is the ? scale.
Correct Answer
Celsius
Centigrade
Explanation
The temperature scale that assigns 0 degrees to the freezing point of water and 100 degrees to the boiling point of water is known as the Celsius or Centigrade scale. Both terms refer to the same scale, which is widely used in most countries around the world.
28.
A system has 30 J of heat added to it and in doing so, it does 25 J of work. The change in internal energy will be:
Explanation
The system has 30 J of heat added to it and does 25 J of work. According to the first law of thermodynamics, the change in internal energy of a system is equal to the heat added to the system minus the work done by the system. Therefore, the change in internal energy will be 30 J - 25 J = +5 J.
29.
All matter is composed of particles that are in constant, random motion. Because of this motion, the particles have ? energy.
Correct Answer
kinetic
Explanation
All matter is composed of particles that are in constant, random motion. This motion is known as kinetic energy. Therefore, the particles in matter possess kinetic energy.
30.
Besides kinetic energy, molecules have rotational kinetic energy, potential energy due to forces between molecules and more. The total of all energies inside a substance is called ? energy.
Correct Answer
internal
Explanation
The explanation for the correct answer is that besides kinetic energy, molecules also possess rotational kinetic energy and potential energy due to forces between molecules. When all these energies are combined, it forms the total energy inside a substance, which is referred to as internal energy.
31.
The second law of thermodynamics would back up this statement:Disorganized energy can be changed to orderly usable energy only by doing work.
Explanation
The second law of thermodynamics states that the natural tendency of energy is to become more disordered over time. This means that disorganized energy cannot spontaneously become orderly and usable energy without the input of work. Therefore, the given statement is supported by the second law of thermodynamics and is true.
32.
The second law of thermodynamics would back up this statement:For natural processes, in the long run, entropy decreases.
Explanation
The second law of thermodynamics states that the entropy of an isolated system tends to increase over time. This means that for natural processes, in the long run, entropy increases rather than decreases. Therefore, the statement that entropy decreases for natural processes in the long run is incorrect.
33.
Which of the following is NOT a unit of heat?
Correct Answer
A. Fahrenheit
Explanation
Fahrenheit is not a unit of heat, but rather a unit of temperature. Heat is measured in units such as joules, calories, and British thermal units, which quantify the amount of energy transferred. Fahrenheit, on the other hand, is a scale used to measure temperature.
34.
Conduction takes place very easily in metals primarily because metals have very "loose" outer ? in their atoms that can drift through the metal and jostle other particles.
Correct Answer
electrons
Explanation
Metals have a unique atomic structure where their outermost electrons are not tightly bound to the nucleus, allowing them to move freely within the metal. These "loose" outer electrons are called valence electrons. Due to their mobility, they can easily drift through the metal lattice and collide with other particles, transferring energy and causing conduction to occur. This high electron mobility is the reason why conduction takes place very easily in metals.
35.
A device in the home that uses a bimetallic strip to turn on or to turn off the furnace is called a ?
Correct Answer
thermostat
Explanation
A thermostat is a device in the home that uses a bimetallic strip to turn on or off the furnace. The bimetallic strip is made up of two different metals with different expansion rates. When the temperature rises, one metal expands more than the other, causing the strip to bend and complete an electrical circuit, turning on the furnace. When the temperature falls, the strip bends in the opposite direction, breaking the circuit and turning off the furnace. Therefore, a thermostat is the correct answer for a device that uses a bimetallic strip to control the furnace.
36.
The second law of thermodynamics would back up this statement:Heat can be completely changed into work.
Explanation
The second law of thermodynamics states that heat cannot be completely changed into work. This law is based on the principle of entropy, which states that in any energy transfer or transformation, the total entropy of a closed system always increases. This means that some amount of heat will always be lost as waste or dissipated into the surroundings, making it impossible for heat to be completely converted into work. Therefore, the statement that heat can be completely changed into work is false.
37.
A heat engine that had no friction present could be 100% efficient.
Explanation
According to the 2nd law of thermodynamics, it is impossible for all of the heat to be changed into work.
38.
The second law of thermodynamics would back up the statement that perpetual motion machines are possible.
Explanation
The second law of thermodynamics states that in any isolated system, the entropy (disorder) of the system will always increase or remain constant. Perpetual motion machines, by definition, would be able to operate indefinitely without an input of energy, which goes against the second law. Therefore, the second law of thermodynamics does not support the possibility of perpetual motion machines, making the statement false.
39.
When heat flows from one object or substance to another it is in contact with, the substances are said to be in ? contact.
Correct Answer
thermal
Explanation
When heat flows from one object or substance to another, the substances are said to be in thermal contact. Thermal contact refers to the physical interaction between two objects or substances that allows heat to transfer between them. This transfer occurs due to the temperature difference between the objects, causing the energy to move from the hotter object to the cooler one. Therefore, when two substances are in thermal contact, heat can flow between them until they reach thermal equilibrium, where their temperatures are equal.
40.
The second law of thermodynamics would back up this statement:In a piston, as heat is added all of the molecules will move in the same direction pushing the piston up.
Explanation
The odds of all of the molecules moving in the same direction are ridiculously low, there are many more ways for them to be moving in different directions and that is what the 2nd law says is more likely to happen.
41.
If the internal energy of a system increases, then the ? of the system will increase.
Correct Answer
A. Temperature
Explanation
When the internal energy of a system increases, it means that there is an increase in the total energy of the system. This increase in energy is typically due to the addition of heat or the performance of work on the system. However, since the question specifically asks about the effect on the system's temperature, we can conclude that when the internal energy increases, the temperature of the system will also increase. This is because temperature is a measure of the average kinetic energy of the particles in the system, and an increase in internal energy implies an increase in the kinetic energy of the particles, leading to a higher temperature.
42.
Which has more internal energy, a bathtub full of cool water or a cup of hot water?
Correct Answer
A. Bathtub full of cool water
Explanation
The bathtub full of cool water has more internal energy compared to a cup of hot water. This is because internal energy is directly related to the temperature of a substance. Although the cup of hot water has a higher temperature, the bathtub contains a larger volume of water, which means it has a greater total internal energy.
43.
When objects are in thermal contact, heat will flow until they are at the same temperature, a condition known as ? ?
Correct Answer
thermal equilibrium
Explanation
When objects are in thermal contact, heat will flow from the object with a higher temperature to the object with a lower temperature until they reach the same temperature. This condition is known as thermal equilibrium. In thermal equilibrium, there is no net flow of heat between the objects because they have reached a state of balance where their temperatures are equal.
44.
Nearly all forms of matter ? when heated due to the fact that the particles will move faster and tend to move farther apart, on the average.
Correct Answer
expand
Explanation
When matter is heated, the particles within it gain energy and start moving faster. This increased movement causes the particles to spread out and move farther apart from each other, resulting in an expansion of the matter. This phenomenon is observed in nearly all forms of matter, including solids, liquids, and gases.
45.
The second law of thermodynamics would back up this statement:Natural systems tend to proceed towards a state of greater order.
Explanation
Replace "order" with "disorder" and it would be true!
46.
What is the ideal efficiency of a heat engine that has a hot reservoir at 500 K and a cold reservoir of 200 K?
Explanation
500-200=300, and 300/500=.60
47.
The term for two metals bonded together that curve when heated is a ? strip.
Correct Answer
bimetallic
Explanation
A bimetallic strip is a term used to describe two different metals that are bonded together and have different coefficients of thermal expansion. When heated, these metals expand at different rates, causing the strip to curve or bend. This property is used in various applications such as thermostats and temperature control devices.
48.
If heat flows from a cup of hot water to a bathtub full of cool water,
the temperature gain of the water in the tub will be ? the temperature
change of the water in the cup.
Correct Answer
A. Smaller than (but opposite sign) than
Explanation
Conservation of energy says the amount of energy (in this case heat) transferred is the same but due to the big mass differences, the temperature change will not be the same.
49.
Radiation involves electromagnetic waves that fall in the ? region.
Correct Answer
infrared
Explanation
Radiation involves electromagnetic waves that fall in the infrared region. Infrared radiation refers to the portion of the electromagnetic spectrum that has longer wavelengths and lower frequencies than visible light. It is commonly associated with heat and is used in various applications such as thermal imaging, remote controls, and night vision technology. Infrared radiation is not visible to the human eye but can be detected and measured using specialized equipment.