You are cooking pasta and putting a pot of water on an electric stove. When the water starts to boil, you add the pasta. What energy transformation occurs to cook the pasta?
a
heat energy to mechanical energy
b
nuclear energy to heat energy
c
electric energy to heat energy
d
mechanical energy to light energy
You are cooking pasta and putting a pot of water on an electric stove. When the water starts to boil, you add the pasta. What energy transformation occurs to cook the pasta?
a
heat energy to mechanical energy
b
nuclear energy to heat energy
c
electric energy to heat energy
d
mechanical energy to light energy
The correct answer is c) electric energy to heat energy. When the pot of water is placed on the electric stove, the electric energy from the stove is transformed into heat energy, which causes the water to heat up and eventually reach boiling point.
Hydroelectric dams work by blocking the path of a water source to create an area with water held back by the dam. The dam can then be opened to allow water to be released. The energy from the moving water is used and transformed into electrical energy. What type of energy does a hydroelectric dam capture as the water passes through?
a
Mechanical Energy
b
Light Energy
c
Sound Energy
d
Nuclear Energy
The correct answer is a) Mechanical energy. As the water passes through the hydroelectric dam, its kinetic energy (due to its movement) is converted into mechanical energy. This mechanical energy is then used to drive turbines, which in turn generate electrical energy.
The picture shows solar panels that power all appliances in this house.CRp0Mm8Ia-8XKLXKgFQVbDPIc6vtyPBid3gdRspXuEgncvMHMofQAo9RWNcOMtuhWkSK21HzjcZz1K6sQZemR2Yii7IZKhKPYJhMcNMXTOkgoZ8AMZrLPz9TL4-Riq9FQUPWkxidgTz87OVcUhwx3p0
An oven is being used to bake cookies in this house. What energy transformations occur when baking cookies in this house?
a
heat energy → light energy → chemical energy
b
light energy → electrical energy → heat energy
c
heat energy → chemical energy → light energy
d
heat energy → electrical energy → chemical energy
The correct answer is a) heat energy → light energy → chemical energy.
When baking cookies in an oven powered by solar panels, the energy transformations occur as follows:
1. Heat energy: The electrical energy from the solar panels is transformed into heat energy, which is used to heat the oven and baking chamber.
2. Light energy: The heat energy inside the oven is then transformed into light energy as the heating elements glow and emit light.
3. Chemical energy: Finally, the light energy is transformed into chemical energy as the cookies undergo a chemical reaction and bake, leading to the formation of delicious cookies.
The total amount of energy in the universe never changes, but the availability of each different type of energy to do work can change tremendously. What best explains this change in available energy?
a
Energy can only be created through nuclear reactions.
b
Energy is always converted with 100 percent efficiency.
c
Energy can only be transferred as heat.
d
Energy is regularly changing from one form into another.
The correct answer is d) Energy is regularly changing from one form into another.
The total amount of energy in the universe is constant, according to the law of conservation of energy. However, energy can change from one form to another. For example, potential energy can be converted into kinetic energy, or mechanical energy can be converted into heat energy.
The availability of each different type of energy to do work can change tremendously because energy is constantly being transformed between different forms. Some forms of energy may be more readily available to do work in a given situation, while others may be less accessible or not useful for performing work.
An aluminum block with a temperature of 300oC is placed into 200 milliliters of water with a temperature of 20oC. Which statement best describes what will be observed in this experiment?
a
Heat will flow from the metal to the water until both are at a temperature somewhere between 20oC and 300oC.
b
Heat will flow from the metal to the water until both are 20oC.
c
Heat will flow from the metal to the water until both are 300oC.
d
Heat will flow from the metal to the water until both are at the temperature of the container.
The correct answer is a) Heat will flow from the metal to the water until both are at a temperature somewhere between 20oC and 300oC.
In this experiment, heat will flow from the aluminum block to the water, as heat tends to move from higher temperature regions to lower temperature regions. The heat transfer will continue until both the aluminum block and the water reach an equilibrium temperature somewhere between the initial temperatures of 20oC and 300oC. The specific equilibrium temperature will depend on the respective thermal properties of the aluminum block and the water.
The diagram below shows two substances, A and B, which are at different temperatures.
What will happen when substance A is dropped into substance B?
a
Substance A and B will exchange heat, and they both will reach 25°C.
b
Substance A will get even warmer as heat flows into it from substance B.
c
Substance A and B will exchange heat, and they both will reach 50°C.
d
Substance A and B will eventually reach the same temperature.
The correct answer is d) Substance A and B will eventually reach the same temperature.
When substance A is dropped into substance B, heat will flow from the hotter substance to the cooler substance until they reach thermal equilibrium. This means that they will eventually reach the same temperature. The specific final temperature will depend on the initial temperatures and thermal properties of substances A and B.
A mixture of gases is heated and rises to the top of its container. Which statement best explains this result?
a
Heated gases will have decreased kinetic energy and decreased density.
b
Heated gases will have increased kinetic energy and decreased density.
c
Heated gases will have increased kinetic energy and increased density.
d
Heated gases will have decreased kinetic energy and increased densit
The correct answer is b) Heated gases will have increased kinetic energy and decreased density.
When gases are heated, their kinetic energy increases. The increase in kinetic energy leads to increased molecular motion and greater spacing between gas particles. As a result, the gas expands and its density decreases. This decrease in density causes the heated gases to rise to the top of their container, as they are lighter than the surrounding cooler gases.
A student wants to show the transfer of heat energy without matter. Which investigation design would best help the student?
a
an investigation of conduction through collisions between particles in space
b
an investigation of radiation through a current in a fluid
c
an investigation of radiation through electromagnetic waves
d
an investigation of conduction through the movement of particles through a solid
The correct answer is c) an investigation of radiation through electromagnetic waves.
Radiation is the transfer of heat energy without the need for matter particles to physically move or collide. Electromagnetic waves, such as light and infrared radiation, can transfer heat energy through space. Therefore, by designing an investigation that explores radiation through electromagnetic waves, the student can demonstrate the transfer of heat energy without the involvement of matter.
During an experiment, a canister filled with hot water was added to a beaker filled with cold water. In which direction did the heat energy move?
a
The heat energy moved from the hot water of the canister into the cold water of the beaker.
b
Equal amounts of heat energy from each container moved in both directions.
c
The heat energy moved from the cold water of the beaker into the hot water of the canister.
d
No heat energy moved, as it all remained in the canister of hot water.
The correct answer is a) The heat energy moved from the hot water of the canister into the cold water of the beaker.
In this experiment, heat energy flows from the higher temperature region (the hot water in the canister) to the lower temperature region (the cold water in the beaker) until thermal equilibrium is reached. This is based on the principle that heat tends to move from areas of higher temperature to areas of lower temperature, in an attempt to equalize the temperature. Therefore, the heat energy moves from the hot water into the cold water.
When energy is conserved or transferred, some energy becomes unavailable to do useful work. What happened to the unavailable energy?
a
It is conducted.
b
It is given off as heat.
c
It is completely destroyed.
d
It is given off as microwaves.
The correct answer is b) It is given off as heat.
When energy is conserved or transferred, some energy becomes unavailable to do useful work. This energy is typically converted into heat. Heat is a form of energy that is transferred due to a difference in temperature, and it tends to disperse and become less concentrated. Therefore, the unavailable energy is given off as heat, which may dissipate into the surroundings.
When handling a metal pan that has been heated on a stove, an oven mitt should always be used to avoid receiving burns. Which of the following is a physical property of the metal pan that requires the use of an oven mitt when it is hot?
a
high thermal conductivity
b
low magnetism
c
low thermal convection
d
high solubility
The correct answer is a) high thermal conductivity.
When a metal pan is heated on a stove, it absorbs and retains heat quickly due to its high thermal conductivity. This means that heat can easily flow through the metal, allowing it to become hot and potentially cause burns if touched directly. The use of an oven mitt provides insulation and protection from the hot surface of the metal pan. Therefore, the high thermal conductivity of the metal pan is the physical property that necessitates the use of an oven mitt when handling it while it is hot.