energy (p1) Flashcards
what are the 8 energy stores
Kinetic, gravitational potential, elastic, thermal, chemical, nuclear, magnetic and electrostatic.
What is the unit for energy?
joules , J
What are the 4 energy transfers?
Mechanical, heating, radiation and electrical
Thermal: Is this an example of a store or a transfer?
store
Heating: Is this an example of a store or a transfer?
transfer
Electrical: Is this an example of a store or a transfer?
transfer
Electrostatic: Is this an example of a store or a transfer?
store
What type of energy is stored in moving objects?
kinetic
What type of energy is stored in objects that have been stretched or squashed?
elastic
What type of energy is stored in objects that have been lifted above ground?
Gravitational potential energy (GPE)
What type of energy is stored in batteries, food and drink?
chemical
What is the equation for gravitational potential energy?
GPE = mass x height x gravitational field strength
What is the equation for kinetic energy?
KE = 0.5 x mass x velocity²
What is the correct unit for mass?
Kilograms, kg
What is the correct unit for extension or height?
Metres, m
What is the conservation of energy law?
Energy can’t be created or destroyed, only transferred
What is a closed system?
A closed system is a collection of objects where neither energy nor matter can leave
What are the equations for power?
Power = energy ÷ time
Power = work done ÷ time
What is the definition of power?
Power is the rate of energy transfer or work done
What is the unit for power?
watts , W
What are the two ways to calculate efficiency?
1) Efficiency = useful energy output ÷ total energy input
2) Efficiency = useful power output ÷ total power input
Can devices be 100 % efficient?
No. Energy is always wasted
What is specific heat capacity?
The amount of energy required to raise the temperature of 1 kg of a substance by 1ºC.
What are the main energy resources available for use on Earth?
Fossil fuels (coal, oil, natural gas); nuclear fuel; biofuel; wind; water (hydroelectric, waves, tides); solar; geothermal
What is the definition for a renewable resource?
A resource that can be replenished as it is being used up
What is the definition for a non-renewable resource?
A resource that is not replenished as it is used up
Fossil fuels: Is this an example of a renewable or non-renewable resource?
non renewable
Which energy resources are non-renewable?
Fossil fuels and nuclear fuels
Nuclear: Is this an example of a renewable or non-renewable resource?
Non-renewable
Hydroelectric power: Is this an example of a renewable or non-renewable resource?
renewable
Solar: Is this an example of a renewable or non-renewable resource?
renewable
Wind: Is this an example of a renewable or non-renewable resource?
renewable
Geothermal: Is this an example of a renewable or non-renewable resource?
renewable
Which energy resource generates the most power?
nuclear fuels
Which energy resources are unreliable due to weather?
wind and solar
Which non-renewable energy resource produces carbon dioxide?
fossil fuels
What environmental issues are caused by fossil fuels?
Fossil fuels: produce CO₂ which causes global warming
What environmental issues are caused by biofuels?
Biofuels: also produce CO₂ when burnt (but this can be off-set by planting more)
What environmental issues are caused by hydroelectric power?
Hydroelectric: reservoirs require the flooding of large areas of land
What environmental issues are caused by solar power?
Solar: large area of ground are covered (cannot be used for crops)
What environmental issues are caused by wind and tidal power generators?
Wind, tidal: can affect the habitats they are in
Is energy always conserved (in a closed system)?
yes
