Energy Flashcards
What are the 8 types of energy store?
chemical
kinetic
gravitational
elastic
thermal
magnetic
electrostatic
magnetic
What are the 4 methods of energy transfer?
Mechanically (whenever a force acts)
Electrically
By heating (conduction, convection, radiation)
by radiation of light and sound
Equation: Efficiency =
Efficiency = useful energy output / total energy input
What are the 3 methods of transfer of heat?
Conduction
Convection
Radiation
Describe conduction of heat.
Best in metals (as they have delocalised electrons)
Worse in air (particles long way apart)
Energy passed on by particles gaining energy and colliding with neighbouring particles to pass the energy along.
Describe convection.
Happens in liquids and gases
Region of air heated, particles move quicker, take up more space.
This less dense air rises
Cooler air is more dense and sinks
This forms a convection current
Describe radiation.
An electromagnetic waves that can travel in a vacuum
Shiny, white surfaces reflect radiation
Matt black surfaces absorb radiation so are the best emitters too
Describe the changes to radiation emitted is the surface becomes hotter.
More radiation emitted if the temp increases
Which 2 heat transfer types are prevented by cavity wall insulation?
conduction as air is trapped and air is a good insulator
convection as air is trapped and cannot form convection currents
How does a puffer jacket keep you warm?
trapped air stops heat transfer by conduction as air is a god insulator
trapped air also stops heat transfer by convection
Why wrap a marathon runner with a foil blanket at the end of the race?
shiny foil reflects the heat back to the runner preventing heat loss by radiation
Name the energy transfers when generating electricity by wind power.
kinetic energy store in the wind
transferred mechanically to
kinetic energy in the turbine
transferred electrically to peoples homes
Name the energy transfers when generating electricity by water power.
gravitational energy store in the water
transferred mechanically to
kinetic energy in the turbine
transferred electrically to peoples homes
Name the energy transfer when generating electricity using geothermal resources.
thermal energy store in the ground
transferred by heating to
thermal energy in steam
transferred mechanically to
kinetic energy store in the turbine
transferred electrically to our homes
Name the energy transfer when using solar heating systems.
energy transferred by radiation from the sun
thermal energy store in the solar heating panels
Name the energy transfer when generating electricity using solar cells.
energy transferred by radiation from the sun
transferred electrically to our homes
Name the energy transfer when generating electricity using fossil fuels.
thermal energy store in the fossil fuels
transferred by heating to
thermal energy in steam
transferred mechanically to
kinetic energy store in the turbine
transferred electrically to our homes
Name the energy transfer when generating electricity using nuclear power.
nuclear energy store in uranium nuclei
transferred by heating to
thermal energy in steam
transferred mechanically to
kinetic energy store in the turbine
transferred electrically to our homes
Equation Work done = force x distance moved
Work done = force x distance moved
How are work done and energy transferred related?
Work done = energy transferred
Equation gravitational PE =
GPE = mgh
Equation Kinetic energy =
KE = 1/2 mv2
What is the principle of conservation of energy?
Energy cannot be created or destroyed only tranformed
Fall a falling object, the energy transfer is ….
GPE lost = KE gained
mgh = 1/2 mv2
For a car stopping, the energy transfer is …
KE lost = Work done by brakes
1/2mv2 = f x d
Power =
Power = work done / time = energy tranfer / time
P = E/t
Advantages and disadvantage of large scale electricity generation using wind
advantages:
renewable
no CO2 emmision so no green house gases
disadvantages:
unreliable as not always windy
location specific
Advantages and disadvantage of large scale electricity generation using water
advantages:
renewable
no CO2 emmision so no green house gases
does not contribute to global warming
disadvantages:
unreliable as not always windy
location specific
can effect local habitat
Advantages and disadvantage of large scale electricity generation using geothermal
advantages:
renewable
no CO2 emmision so no green house gases
so does not contribute to global warming
reliable
disadvantages:
location specific, eg Iceland due to needing thin crust
Advantages and disadvantage of large scale electricity generation using solar heating systems
advantages:
renewable
no CO2 emmision so no green house gases
so does not contribute to global warming
disadvantages:
unreliable as require daylight so won’t work at night
Advantages and disadvantage of large scale electricity generation using solar
advantages:
renewable
no CO2 emmision so no green house gases
so does not contribute to global warming
disadvantages:
unreliable as require daylight so won’t work at night
Advantages and disadvantage of large scale electricity generation using fossil fuels
advantages:
reliable as can generate 24 /7
cheap to build
disadvantages:
CO2 emmision so green house gases given off
contributes to global warming
non renewable
Advantages and disadvantage of large scale electricity generation using nuclear
advantages:
no CO2 emmision so no green house gases
so does not contribute to global warming
reliable as can generate 24 /7
disadvantages:
need to dispose of radiactive waste
dangers of melt down causing radiation leaks
