Flashcards in physics p2, energy resources and energy transfer Deck (41):
9 types of energy- CLENT KEGS
7- ELASTIC POTENTIAL
8- GRAVITATIONAL POTENTIAL
what are chemical and potential forms of?
what's the principle of the conservation of energy?
energy can never be created nor destroyed- it's only ever transferred from one to another
useful energy output/ total energy input
no device is 100% efficient and...
...the wasted energy is always dissipated as heat
electrical devices convert ELECTRICAL ENERGY->
batteries convert CHEMICAL ENERGY->
electrical-> kinetic, heat, sound, light
GPE and ELASTIC POTENTIAL always get converted into ->
how can heat be transferred?
by radiation, conduction or convection
what is thermal radiation the transfer of?
heat energy by electromagnetic waves- objects are continually absorbing and emmiting heat radiation. an object that's hotter than its surroundings emits more radiation than it absorbs and vice versa
what is conduction?
in a solid: the process where vibrating particles pass on their extra kinetic energy to neighbouring particles. the vibrations are passed on to the near by aprticles
what is convection?
where more energetic particles move from the hotter region to the cooler region- and take their heat energy with them
how does an immersion heater work?
1) heat energy is transferred from the heater coils to the water by conduction
2) the particles near the coils get more energy so move faster- more distance between them so water expands and becomes less dense
3)this reduction in density means that hotter water tends to rise about the denser, cooler water
4) as the hot water rises it displaces the colder water making it sink to the heater coils.
5) this cold water is then heated by the coils and rises-cycle is continuous. you end up with convection currents going up round and down, circulating the heat energy through the water
where is convection most efficient?
in roundish or squarish containers- allow convection currents to work best
change in density
hot, less dense air rises- displaces cooler air, cooler air flows to replace it
what is work done?
the energy transferred
what happens when a force moves an object?
energy is transferred and work it done
work done (J)=
force x distance
what is power?
the rates of energy transfer or the rate of doing work
power (W) or (J/s)=
kinetic energy gained=
what are 4 non-renewable energy resources?
3) natural gas
4) nuclear fuels (uranium and plutonium)
what are the energy transfers in a power station?
CHEMICAL ENERGY (fuel)--> HEAT ENERGY (steam)--> KINETIC ENERGY(turbine-> spins generator) --> ELECTRICAL ENERGY (generator-> national grid)
what are the energy transfers in nuclear reactors?
NUCLEAR ENERGY-> HEAT ENERGY-> KINETIC ENERGY-> ELECTRICAL ENERGY
energy transfers in wind farms?
K.E ->ELECTRICAL in moors, on coast, out at sea
energy transfers in geothermal energy?
HEAT-> KINETIC-> ELECTRICAL - water is pumped in pipes down to hot rocks and forced back up due to pressure to turn a turbine drives a generator
energy transfers in solar cells?
LIGHT ENERGY-> ELECTRICAL- generate direct current
solar panels- black water pipes inside glass box- glass lets heat and light from sun in and absorbed by black pipes to heat up water
cooking with solar power- use curved mirror to focus sun's light and heat same in solar oven-slow bulky and unreliable
energy transfers in wave power?
K.E of waves-> ELECTRICAL ENERGY - lots of wave converters around the coast- up and down motion of tide drives a generator
energy transfers of tidal barrages?
K.E -> ELECTRICAL big dams built across river estuaries with turbines in them. tide fills them to 7m and water is allowed through turbines which drives them on the way in and a generator
energy transfers in hydroelectric power?
GPE-> KE-> ELECTRICAL- flooding of valley by building a dam- rainwater is caught and allowed out through turbines
energy transfers of pumped storage?
GPE-> KE-> ELECTRICAL- storing spare energy for later use
most large power stations have boilers which are kept running all night even when demand is low- surplus of electricity at night- storing energy for later use.
pumps water up to a higher reservoir which can be released quickly during periods of peak demand to supplement the steady delivery from the big power stations.a way of storing energy that has already been generated
what are the advantages of burning fossil fuels?
1) releases a lot of energy, relatively cheaply
2) energy from fossil fuels doesn't rely on the weather like lots of renewable energy= reliable
3) already lots of fossil fuel power stations so don't need to spend money on new technology
what are the disadvantages of burning fossil fuels?
1) release CO2 into the atmosphere which contributes to global warming and climate change
2) burning coal and oil releases sulfur dioxide SO2, which causes acid rain- harms trees and soils having a huge affect on wildlife
3) they will eventually run out
what are the advantages and disadvantages of nuclear power?
ADV: doesn't produce any of the greenhouse gases
still plenty of uranium left in the ground
DISADV: - nuclear reactors are expensiveto build and maintain
- take longer to start up than fossil fuels
- processing the uranium before can cause pollution
-always a risk of leaks of radioactive material or a major catastrophe like at Chernobyl
- radioactive waste
- when too old and inefficient, nuclear power stations have to be decommissioned= expensive
what are the advantages and disadvantages of wind farms?
ADV:- quite cheap to run
-tough and reliable
-wind is free
- doesn't produce any polluting waste
DISADV: - spoil the view
- need 1500 wind turbines to replace 1 coal-fired power station- covers a lot of ground
- wind isn't always strong enough to generate any power so impossible to increase supply when there's extra demand
- expensive to set up especially out at sea
what are the advantages and disadvantages of geothermal energy?
ADV: free, renewable, no real environmental problems
DISADV: cost of drilling down several km
- cost of building a power plant is often high compares to the amount of energy we get out of it
- few places where this seems to be an economic option
what are the advantages and disadvantages of solar energy?
- the Sun provides renewable energy source
- energy is free and running costs are almost nil
- no pollution
- the cells can be linked to rechargeable batteries to create a system that can store energy during the day for use at night
- good to power calculators or watches as don't use much energy
-used in remote places where not much choice and in satellites
- used to generate on a small scale- individual homes
- not practical or too expensive to connect them to the National Grid
- solar cells can only generate enough electricity to be useful if they have enough sunlight- problem at night
what are the advantages and disadvantages of wave power?
ADV: - no pollution
-useful on small islands
DISADV: spoiling the view
-hazard to boats
- fairly unreliable- waves die out when wind drops
-initial coast are high
-unlikely to provide energy on a large scale
what are the advantages and disadvantages of tidal barrages?
ADV: -no pollution
-tides are pretty reliable
- no fuel costs and minimal running costs
DISADV: prevent free access by boats,
-spoil the view
- alter the habitat of the wildlife
-height of the wave is variable so lower tides will provide less energy than higher ones
- initial costs are moderately high