Define energy stores .

Energy stores refer to the different ways in which energy is stored in objects.

True or False? Energy is measured in units of kilograms.

False. Energy is measured in units of joules (J).

Define a system in physics.

A system is an object or group of objects.

True or False? Magnetic and electrostatic are examples of energy stores used in physics.

True. Magnetic and electrostatic are examples of energy stores used in physics. Other examples include kinetic, gravitational potential, elastic, chemical, nuclear, and thermal.

True or False? Objects have energy in their elastic potential store if they are stretched, squashed or bent.

True. Objects have energy in their elastic potential store if they are stretched, squashed or bent.

True or False? All objects have energy in their thermal store, the hotter the object, the less energy it has in this store.

False. All objects have energy in their thermal store, the hotter the object, the more energy it has in this store.

What is the definition of energy transfer pathways ?

Energy transfer pathways are the ways that energy can be transferred from one energy store to another.

True or False? Energy is transferred only through mechanical pathways.

False. Energy can be transferred through various pathways, including mechanical, electrical, heating, and radiation.

Define mechanical working in terms of energy transfer.

Mechanical work is the transfer pathway when a force is exerted over a distance.

True or False? In a falling object, energy is transferred from its kinetic store to its gravitational potential store.

False. In a falling object, energy is transferred from its gravitational potential store to its kinetic store.

State the four energy transfer pathways used in physics.

The four energy transfer pathways used in physics are: mechanical electrical heating radiation

True or False? An example of energy transfer by heating is a hot chocolate warming up cold hands.

True. An example of energy transfer by heating is a hot chocolate warming up cold hands.

True or False? The total amount of energy in a closed system can change over time.

False. The total amount of energy in a closed system remains constant; it cannot change over time according to the principle of conservation of energy.

What does an energy flow diagram show?

An energy flow diagram represents energy stores and transfers within a system, showing both the stores and the transfers taking place.

State the principle of conservation of energy.

The principle of conservation of energy states that energy cannot be created or destroyed; it can only be transferred from one energy store to another.

Define what is meant by the term dissipated to the surroundings .

When energy is dissipated to the surroundings , it means that energy has been transferred to the surroundings and cannot easily be used for a specific purpose. Dissipated energy is a form of wasted energy .

For a system in which energy is conserved, what is an equation relating wasted energy , total energy input and useful energy output ?

The equation representing the conservation of energy is: total energy input = useful energy output + wasted energy

What is a Sankey diagram ?

Sankey diagrams are graphical representations of energy transfers, characterised by splitting arrows that show the proportions of energy transfers taking place.

What do the different parts of a Sankey diagram represent?

The left-hand side of a Sankey diagram represents the energy transferred into the system, while the straight arrow pointing to the right represents the useful energy output. The curved arrows represent wasted energy.

True or False? Total energy input a closed system equals useful energy output plus wasted energy.

True. According to the principle of conservation of energy, the total energy input in a closed system is equal to the useful energy output plus the wasted energy.

An energy transfer has an efficiency of 0.4. What are the percentages of useful energy output and wasted energy?

If an energy transfer has an efficiency of 0.4, 40% of the energy is transferred usefully and 60% of the energy is wasted.

True or False? Thermal conduction in solids occurs when hotter, more energetic atoms or ions vibrate faster and collide with neighbouring atoms or ions.

True. Thermal conduction in solids occurs when hotter , more energetic atoms or ions vibrate faster and collide with neighbouring atoms or ions, transferring energy throughout the structure of the solid.

Why does thermal conduction generally occur faster in metals than non-metals?

Thermal conduction occurs faster in metals because metals have free (delocalised) electrons , which speed up the energy transfer throughout the substance.

True or False? Thermal conduction does not happen in liquids or gases because the particles are too far apart.

False. Thermal conduction does happen in liquids and gases, but they tend to be poor conductors because the particles are further apart than in solids.

True or False? Convection cannot happen in solids.

True. Convection only happens in liquids and gases because the particles are free to move around. It cannot happen in solids because the particles are held in a rigid structure.

How is a convection current set up when a fluid is heated?

When a fluid is heated, the space between particles increases, so the density of the fluid decreases which causes it to rise, and cooler, denser fluid takes its place.

True or False? All objects emit thermal radiation.

True. All objects emit thermal radiation. The hotter an object is, the more thermal radiation it emits.

True or False? The colour of an object affects its ability to emit and absorb radiation.

True. The colour of an object does affect its ability to emit and absorb thermal radiation.

True or False? White surfaces are good emitters and good absorbers of thermal radiation.

False. White surfaces are poor emitters and poor absorbers of thermal radiation.

What colour surface is the best emitter of thermal radiation?

Black surfaces are the best emitters of thermal radiation.

True or False? Shiny surfaces are very good emitters of thermal radiation.

False. Shiny surfaces are very poor emitters of thermal radiation. They are also very poor absorbers because they reflect the infrared radiation.

How is energy transfer by conduction reduced?

Energy transfer by conduction can be reduced by using an insulator .

What are the three factors that the effectiveness of an insulator is dependent upon?

The three factors that the effectiveness of an insulator are dependent on are: the thermal conductivity of the material the density of the material the thickness of the material

What feature of fibreglass insulation makes it a good insulator?

The air trapped between the fibres of fibreglass insulation makes it a good insulator.

What is the purpose of cavity wall insulation?

The purpose of cavity wall insulation is to reduce energy transfer by conduction through the walls of buildings.

IGCSEPhysicsEdexcelFlashcards4. Energy Resources & Energy TransfersEnergy Stores & Transfers

Energy Stores & Transfers (Edexcel IGCSE Physics)

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Cards in this collection (37)

Define energy stores.
Energy stores refer to the different ways in which energy is stored in objects.
True or False?
Energy is measured in units of kilograms.
False.
Energy is measured in units of joules (J).
Define a system in physics.
A system is an object or group of objects.
True or False?
Magnetic and electrostatic are examples of energy stores used in physics.
True.
Magnetic and electrostatic are examples of energy stores used in physics. Other examples include kinetic, gravitational potential, elastic, chemical, nuclear, and thermal.
True or False?
Objects have energy in their elastic potential store if they are stretched, squashed or bent.
True.
Objects have energy in their elastic potential store if they are stretched, squashed or bent.
True or False?
All objects have energy in their thermal store, the hotter the object, the less energy it has in this store.
False.
All objects have energy in their thermal store, the hotter the object, the more energy it has in this store.
What is the definition of energy transfer pathways?
Energy transfer pathways are the ways that energy can be transferred from one energy store to another.
True or False?
Energy is transferred only through mechanical pathways.
False.
Energy can be transferred through various pathways, including mechanical, electrical, heating, and radiation.
Define mechanical working in terms of energy transfer.
Mechanical work is the transfer pathway when a force is exerted over a distance.
True or False?
In a falling object, energy is transferred from its kinetic store to its gravitational potential store.
False.
In a falling object, energy is transferred from its gravitational potential store to its kinetic store.
State the four energy transfer pathways used in physics.
The four energy transfer pathways used in physics are:
- mechanical
- electrical
- heating
- radiation
True or False?
An example of energy transfer by heating is a hot chocolate warming up cold hands.
True.
An example of energy transfer by heating is a hot chocolate warming up cold hands.
True or False?
The total amount of energy in a closed system can change over time.
False.
The total amount of energy in a closed system remains constant; it cannot change over time according to the principle of conservation of energy.
What does an energy flow diagram show?
An energy flow diagram represents energy stores and transfers within a system, showing both the stores and the transfers taking place.
State the principle of conservation of energy.
The principle of conservation of energy states that energy cannot be created or destroyed; it can only be transferred from one energy store to another.
Define what is meant by the term dissipated to the surroundings.
When energy is dissipated to the surroundings, it means that energy has been transferred to the surroundings and cannot easily be used for a specific purpose. Dissipated energy is a form of wasted energy.
For a system in which energy is conserved, what is an equation relating wasted energy, total energy input and useful energy output?
The equation representing the conservation of energy is:
total energy input = useful energy output + wasted energy
What is a Sankey diagram?
Sankey diagrams are graphical representations of energy transfers, characterised by splitting arrows that show the proportions of energy transfers taking place.
What do the different parts of a Sankey diagram represent?
The left-hand side of a Sankey diagram represents the energy transferred into the system, while the straight arrow pointing to the right represents the useful energy output. The curved arrows represent wasted energy.
State the equation for calculating wasted energy in a Sankey diagram.
The equation for calculating wasted energy is:
$wasted energy = total energy in - useful energy out$
True or False?
Total energy input a closed system equals useful energy output plus wasted energy.
True.
According to the principle of conservation of energy, the total energy input in a closed system is equal to the useful energy output plus the wasted energy.
An energy transfer has an efficiency of 0.4. What are the percentages of useful energy output and wasted energy?
If an energy transfer has an efficiency of 0.4, 40% of the energy is transferred usefully and 60% of the energy is wasted.
An energy transfer is 80% efficient. The total energy input is 200 J. State the amount of wasted energy in joules.
The energy transfer is 80% efficient, so 20% of the energy is wasted. The total energy input is 200 J; therefore, the wasted energy is 40 J.
- wasted energy is equal to 20% of the total energy input
- $wasted energy = 0.2 \times 200 = 40 J$
True or False?
Thermal conduction in solids occurs when hotter, more energetic atoms or ions vibrate faster and collide with neighbouring atoms or ions.
True.
Thermal conduction in solids occurs when hotter, more energetic atoms or ions vibrate faster and collide with neighbouring atoms or ions, transferring energy throughout the structure of the solid.
Why does thermal conduction generally occur faster in metals than non-metals?
Thermal conduction occurs faster in metals because metals have free (delocalised) electrons, which speed up the energy transfer throughout the substance.
True or False?
Thermal conduction does not happen in liquids or gases because the particles are too far apart.
False.
Thermal conduction does happen in liquids and gases, but they tend to be poor conductors because the particles are further apart than in solids.
True or False?
Convection cannot happen in solids.
True.
Convection only happens in liquids and gases because the particles are free to move around. It cannot happen in solids because the particles are held in a rigid structure.
How is a convection current set up when a fluid is heated?
When a fluid is heated, the space between particles increases, so the density of the fluid decreases which causes it to rise, and cooler, denser fluid takes its place.
True or False?
All objects emit thermal radiation.
True.
All objects emit thermal radiation. The hotter an object is, the more thermal radiation it emits.
True or False?
The colour of an object affects its ability to emit and absorb radiation.
True.
The colour of an object does affect its ability to emit and absorb thermal radiation.
True or False?
White surfaces are good emitters and good absorbers of thermal radiation.
False.
White surfaces are poor emitters and poor absorbers of thermal radiation.
What colour surface is the best emitter of thermal radiation?
Black surfaces are the best emitters of thermal radiation.
True or False?
Shiny surfaces are very good emitters of thermal radiation.
False.
Shiny surfaces are very poor emitters of thermal radiation. They are also very poor absorbers because they reflect the infrared radiation.
How is energy transfer by conduction reduced?
Energy transfer by conduction can be reduced by using an insulator.
What are the three factors that the effectiveness of an insulator is dependent upon?
The three factors that the effectiveness of an insulator are dependent on are:
- the thermal conductivity of the material
- the density of the material
- the thickness of the material
What feature of fibreglass insulation makes it a good insulator?
The air trapped between the fibres of fibreglass insulation makes it a good insulator.
What is the purpose of cavity wall insulation?
The purpose of cavity wall insulation is to reduce energy transfer by conduction through the walls of buildings.

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