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Physics > P3- Sustainable Energy > Flashcards

P3- Sustainable Energy Flashcards

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1
Q

What does the power tell you?

A

The power of an appliance tells you how fast it transfers energy from the charge passing through it.

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2
Q

What is power measured in?

A

Power is measured in watts (W) or kilowatts (kW).

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3
Q

Equation for energy transferred?

A

Energy transferred (joules) = power (W) * time (s)

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4
Q

What is energy measured in?

A

Energy is measured in joules.

However, one joule is a tiny amount of electrical energy.

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5
Q

What is a kilowatt hour?

A

A kilowatt hour is the amount of electrical energy converted by a 1kW appliance left on for one hour.

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6
Q

Equation for energy transferred?

A

Energy transferred (kilowatt hours) = power (kilowatts) * time (hours)

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7
Q

Equation for cost?

A

Cost = number of kWh * cost per kWh.

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8
Q

Equation for power?

A

Power (W) = voltage (V) * current (A)

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9
Q

Where does energy come from?

A

An appliance with high power transfers a lot of energy in a short time. This energy comes from the current flowing through it.

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10
Q

Equation for efficiency?

A

Efficiency= energy usefully transferred / total energy supplied * 100

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11
Q

Equation for efficiency of sankey diagram?

A

Efficiency = useful energy output / energy input.

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12
Q

Efficiency of generation?

A

Efficiency = electrical energy from generator/ energy input from coal.

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13
Q

Efficiency of distribution?

A

Efficiency = useful electrical energy output/ electrical energy from the generator.

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14
Q

Overall efficiency?

A

Efficiency = useful electrical energy output/ energy input from coal.

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15
Q

Reducing heat transfer?

A
  • Installing cavity walls
  • Loft insulation
  • Double glazing
  • Drought proofing reduces the heat lost through gaps in walls, ceilings,windows and doors.
  • Thick curtains
  • Fibreglass wool hot water tank jacket.
  • Energy saving light bulbs
  • Turning down the heating
  • Wash clothes at low temperature
  • Switch lights off
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16
Q

Workplaces & government save electricity??

A
  • Businesses generate a lot of paperwork. Energy would be saved by not printing and photocopying unnecessary things.
  • People should cycle, share a car or use public transport to get to work.
  • The government should encourage people to save electricity- by giving grants for loft insulation, running schemes to trade old boilers with efficient ones and improving public transport.
  • They can also invest in alternative energy sources, improve recycling service and making law that new homes and businesses are efficient.
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17
Q

Electricity?

A

Electricity is a secondary energy source. It is convenient because it can be easily transmitted over long distances via national grid.

18
Q

Non renewable sources?

A
  • Fossil fuels; coal, oil & gas.
  • Nuclear fuels (uranium & plutonium)
  • They will all run out one day
  • They all damage the environment
  • They currently provide most of our energy
19
Q

Renewable sources?

A
  • Wind
  • Waves
  • Tides
  • Hydroelectric
  • Biofuels
  • Geothermal
  • Solar
  • They will never run out
  • They do damage the environment but less than non renewable sources
  • They don’t provide much energy and can be unreliable of they depend on the weather
20
Q

Thermal power stations?

A
  • Energy is released from the fuel (from burning in the boiler) and used to generate steam.
  • The steam turns the turbines.
  • A generator converts the movement of the turbines into electricity.
  • In many renewable sources, the energy drives the turbines directly.
21
Q

Fossil fuels causes environmental problems?

A
  • All fossil fuels (oil,gas and coal) release carbon dioxide in the atmosphere when burnt in power stations.
  • All this CO2 contributes to global warming and climate change.
  • Burning coal and oil releases sulfur dioxide which causes acid rain. Acid rain harms trees and environment.
  • Coal mining ruins the landscape.
  • Oil spillages causes harm to creatures living in and around the sea.
  • Fossil fuels produce a lot of energy and cheaply. They don’t rely on the weather.
22
Q

Equation for speed?

A

Speed (m/s) = distance travelled (m) / time taken (s)

23
Q

Moving a magnet in a coil?

A
  • You can create a voltage and maybe a current in a conductor by moving a magnet in or near a coil of wire.
  • This is called electromagnetic induction.
  • As you move the magnet, the magnetic field through the coil changes- this change in the magnetic field induces a voltage. And a current flows in the wire.
  • Generators use electromagnetic induction to turn kinetic energy from the turbines in power stations into mains electricity.
  • In a generator a magnet rotates in a coil of wire. As the magnet turns the magnetic field through the coil changes - this change induces a voltage. Which makes a current flow through the coil.
  • If you want a bigger voltage and current you turn the magnet faster.
  • To move the magnet faster you need to put more energy in to turn the turbine which uses up more primary energy source.
24
Q

The national grid?

A
  • The national grid is the network of pylons and cables that cover the whole of Britain.
  • It takes electricity from power stations to homes and industry.
  • It enables power to be generated anywhere on the grid. Then to be supplied anywhere on the grid.
  • To transmit a huge amount of power needed you need either a high voltage or a high current.
  • However, you loose lots of energy through heat in the cables.
  • It is cheaper and more efficient to distribute at a really high voltage- this keeps the current low and reduces energy loss.
  • The voltage is reduced before it reaches out homes- at 230V. This is mains supply voltage.
25
Q

Nuclear power stations?

A
  • Nuclear fusion produces the heat to make steam to drive turbines.
  • In nuclear fusion, atoms in the nuclear fuel are split into two releasing lots of heat energy.
  • Water is used as a coolant, to take away the heat produced by the fusion process. This heat is used to produce steam to drive a turbine and generator.
26
Q

Advantages of nuclear power?

A
  • Releases more energy than chemical reactions (like burning)
  • Doesn’t produce CO2 when making electricity.
  • Nuclear fuel is cheap.
27
Q

Disadvantages of nuclear power?

A
  • Produces radioactive waste which emits ionising radiation and is difficult to dispose- very dangerous.
  • The overall cost is high due to the price of the power plant and final decommissioning.
  • People who live nearby are scared of the risks.
28
Q

Danger of ionising radiation?

A
  • Increased exposure to ionising radiation increases the damage done to cells.
  • High doses of ionising radiation kills cells directly causing radiation sickness.
  • Lower doses damage cells but don’t kill them. Which can cause cancer.
29
Q

What is irradiation?

A

Being exposed to radiation without coming into contact with the source.

The damage done to the body stops when you leave the area where the radioactive waste is.

So you are exposed for a short period of time. Therefore you receive a lower dose.

30
Q

What is contamination?

A

Picking up some radioactive waste. (By breathing it, drinking contaminated water or getting it on your skin)

You are still exposed even when you leave the area. It leaves people exposed to ionising damage for a long time- leading to more damage.

31
Q

Wind power?

A
  • Involves putting windmills in exposed areas like moors or coasts.
  • Each wind turbine has its own generator inside it so the electricity is generated directly.
  • There’s no pollution.
  • They spoil the view- 1500 wind turbines replace 1 coal fired power station.
  • They make noise- disturbs people living nearby.
  • No power when wind stops.
  • Initial costs are high but no fuel costs and minimal running costs.
  • No permanent damage done.
32
Q

Solar cells?

A
  • Solar cells generate electric currents directly from sunlight.
  • They are initially expensive. But after that the energy is free.
  • Use in remote places.
  • Used in watches and calculators
  • No pollution
  • In hot countries it’s very reliable.
  • Used to generate electricity on a small scale
33
Q

Wave power?

A
  • Wave powered turbines in the Coast.
  • As the waves come to shore, the up and down motion directly drives the turbines then the generator.
  • No pollution
  • Spoils the view
  • A hazard to boats
  • Unreliable- waves die when the wind drops.
  • Initial costs are high
  • No fuel costs and minimal running costs.
  • Useful on small islands not on the large scale.
34
Q

Tidal barrages?

A
  • Big dams built across river estuaries with turbines in them.
  • As the tide comes in it lifts the estuary several metres and drives the turbines.
  • The source of the energy is the gravity of the Sun and the Moon.
  • No pollution
  • Prevents free access by boats.
  • spoils the view
  • Alters the habitat of wildlife.
  • Reliable
  • Initial costs are high
  • No fuel costs and minimal running costs
35
Q

Biofuels?

A
  • Are renewable energy resources.
  • They are used to generate electricity in thermal power stations.
  • They are burnt to heat up water.
  • They can be used in some cars.
  • They can be solids,liquids or gases.
  • They are quick
36
Q

Geothermal?

A
  • Only possible where hot rocks lie near the surface.
  • Used to drive generators in thermal power stations.
  • Free renewable energy
  • No environmental damage
  • However, the cost of drilling down several km of hot rock is expensive
37
Q

Hydroelectricity?

A
  • Requires flooding a valley by building a big dam.
  • Rainwater is caught and allowed through the turbines- driving them directly.
  • The turbines drive generators to make electricity.
  • No pollution
  • Rotting vegetation releases methane and CO2.
  • Species lose their habitat.
  • Reservoirs can be dried out
  • Reliable except in droughts
  • Initial costs are high, no fuel costs and no minimal running costs.
38
Q

What does Britain need?

A
  • Renewable sources struggle to produce the same sort of energy output as power stations.
  • All our uranium and over half of coal we burn is imported from other countries.
  • We are dependant on other countries. Transport related cost and CO2 emissions.
  • Our fossil fuels will run out in 50 years.
39
Q

Considered environmental impacts??

A
  • Renewables have low running costs- no fuel costs.
  • Renewable resources need bigger power stations than non renewables producing the same output- expensive.
  • Nuclear reactors,hydroelectric dams and geothermal power stations needs engineering- expensive.
  • Waste pollution
  • CO2 emissions
40
Q

How is energy transferred?

A

Anything that supplies electricity is also supplying energy.

Cells,batteries and generators all transfer energy to the charge in the wire. Which then transfers it to the components or devices in the circuit.

The components then transfer energy to the environment in the form of light,heat, sound etc.

Physics (7 decks)

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