Energy transfer and efficiency Flashcards
What is thermal energy?
Thermal energy is where an object at a higher temperature has greater thermal energy.
examples: heater, the Sun and hot water
What is light energy?
Light energy is where light is a wave that is emitted from anything at a very high temperature.
examples: lamps, stars and fire
What is electrical energy?
Electrical energy is usually associated with electric current
examples: mains supply, overhead cables and output from a transformer
What is sound energy?
Sound energy is where an object vibrates and emits sound.
examples: buzzer, bell, siren and person talking
What is kinetic energy?
Kinetic energy is energy due to movement.
examples: person running, high-speed train and planet orbiting the Sun
What is chemical energy?
Chemical energy is energy stored by atoms.
examples: food, chemical cell and coal
What is nuclear energy?
Nuclear energy is energy stored by the nuclei of atoms.
What is elastic potential energy?
Elastic potential energy is where an object that has been pulled or squashed.
example: a stretched rubber band and cables supporting a bridge
What is gravitational potential energy?
Gravitational potential energy is energy due to an object’s position in the Earth’s gravitational field. An object lifted higher will have greater gravitational potential energy.
examples: aeroplane in the sky and person up a ladder
What does chemical energy produce?
chemical energy -> thermal energy + light energy + sound energy
What is the principle of conservation of energy?
This is where energy can’t be created or destroyed but can be transferred from one form to another.
Give one reason why heat energy might be wasted?
Heat energy might be wasted due to electric currents following in wires of due to friction between moving surfaces.
What is efficiency?
Efficiency is a measure of how well a device transfers energy in the form we can.
How is efficiency calculated?
efficiency = useful energy transferred by the device / total energy supplied by the device x 100%
What are sankey diagrams?
Sankey diagrams are energy-transfer diagrams that show the different forms of energy takes during a transfer. The thickness of the arrow in the diagram is drawn to scale to show the amount of energy transferred.
What can all object do to do with infrared radiation?
All objects can emit infrared radiation, absorb infrared radiation and reflect infrared radiation.
What does the amount of infrared radiation emitted by an object depend on?
The amount of infrared radiation emitted by an object depends on its temperature and its surface.
Give 2 reasons to why a dull black surface loses energy more quickly than a bright shiny surface:
- a dull black surface is a good radiator of heat
- a bight shiny surface is a poor radiator of heat
What is the difference between a dull black surface and a bright shiny surface?
A dull black surface is a good absorber of heat radiation where as a bright shiny surface is a poor absorber, as it reflects the heat radiation away.
What is thermal equilibrium?
Thermal equilibrium is where eventually, the rate of heat absorption will equal the rate of heat radiation and the temperature remains steady.
What do all atoms have?
All atoms have both kinetic energy and potential energy.
What happens when substances are heated?
When substances are heated, the temperature increases and the atoms gain more kinetic energy.
What is the heat energy of a substance the total of?
The heat energy of a substance is the total kinetic energy and potential energy of all the atoms in the substance.
How can you investigate the different rates of heat radiation of different surfaces?
To investigate the different rates of heat radiation of different surfaces, you can compare the temperature over time of a silvered beaker and blackened beaker.
