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GCSE Physics P2 (OCR B712): Living For The Future (Energy Resources)

Year 10 revision topics

P2a Collecting energy from the Sun
  1. Recall that photocells:
    • transfer light into electricity
    • produce direct current (DC)
    • can operate in remote locations
    • have a power or current that depends on the surface area exposed to sunlight.
  • Recall that DC electricity is current in the same direction all the time.
  1. Describe how the Sun's energy can be harnessed:
    • radiation from the Sun can be absorbed by a surface and transferred into heat energy
    • produces convection currents (wind) to drive turbines
    • how glass can be used to provide passive solar heating for buildings
    • light can be reflected to a focus by a curved mirror.
  1. Describe some advantages and disadvantages of using photocells to provide electricity:
    • low maintenance
    • no need for power cables
    • no need for fuel
    • long life
    • renewable energy resource
    • no polluting waste
    • no power at night or in bad weather
  1. Describe how light produces electricity in a photocell (HL):
    • energy absorbed by photocell
    • electrons are knocked loose from the silicon atoms in the crystal
    • electrons flow freely.
  1. Understand how the current and power produced in a photocell depends on (HL):
    • light intensity
    • surface area exposed
    • distance from the light source
  1. Describe the advantages and disadvantages of wind turbines:
    • renewable
    • no polluting waste
    • visual pollution
    • dependency on wind speed
    • appropriate space and position needed.
  1. Explain why passive solar heating works (HL):
    • glass is transparent to Sun's radiation
    • heated surfaces emit infrared radiation of longer wavelength
    • glass reflects this longer wavelength infrared
  • Recall that an efficient solar collector must track the position of the Sun in the sky. (HL)
P2b Generating electricity
  • Describe how to generate electricity using the dynamo effect, by moving the coil or the magnet.
  • Recall that a generator produces alternating current(AC).
  • Recall that a battery produces direct current (DC).
  1. Describe the main stages in the production and distribution of electricity:
    • source of energy
    • power station produces electricity
    • national grid of power lines connecting station to consumers
    • consumers are homes, factories, offices and farms
  • Recognise that there is significant waste of energy in a conventional power station.
  1. Use the equation in the context of a power station:

  2. given the useful energy output and the total energy input. Efficiency can be expressed in ratio or percentage terms.
  • Describe and recognise the ways that the dynamo effect can be increased (to give more current).
  • Describe and interpret AC using a voltage-time graph.
  1. Describe how simple AC generators work:
    • coil of wire
    • magnetic field
    • coil and field close
    • relative motion between coil and field
  1. Describe how electricity is generated at a conventional power station:
    • burning fuel
    • producing steam
    • spinning a turbine
    • turbine turns generator
  • Use the equation in the context of a power station:


    given the useful energy output, wasted energy and the total energy input. Efficiency can be expressed in ratio or percentage terms.
  • Use the equation in the context of a power station to calculate useful energy output, total energy input or wasted energy.(HL)


    Efficiency can be expressed in ratio or percentage terms.
P2c: Global warming
  • Understand that some gases in the Earth's
  • atmosphere prevent heat from radiating into space.
  • Recall and recognise that this is known as the greenhouse effect.
  1. Recall and identify examples of greenhouse gases to:
    • carbon dioxide
    • water vapour
    • methane
  1. Describe reasons for climate change caused by increased global warming:
    • increased energy use
    • increased CO2 emissions
    • deforestation.
  • Describe the difficulties of measuring global warming.
  • Explain why scientists working on global warming should allow other scientists to use their data.
  • Describe how electromagnetic radiation at most wavelengths can pass through the Earth's atmosphere, but certain wavelengths, particularly infrared, are absorbed by some gases in the atmosphere.
  1. Explain the greenhouse effect in terms of: (HL)
    • short wavelength e-m radiation from the Sun is absorbed by and heats the Earth
    • the Earth radiates heat as longer wavelength infrared radiation
    • greenhouse gases absorb some infrared radiation, warming the atmosphere.
  • Recall and identify natural and man-made sources of greenhouse gases (limited to water vapour, carbon dioxide and methane).
  • Interpret data about the abundance and relative impact of greenhouse gases (limited to water vapour,carbon dioxide and methane) (HL).
  1. Explain how human activity and natural phenomena both have effects on weather patterns including dust in the atmosphere:
    • from factories reflecting radiation from the city back to Earth causing warming
    • from volcanic ash and gases reflecting radiation from the Sun back into space causing cooling.
  • Interpret data about increased global warming and climate change as a result of natural or human activity (no recall is expected) (HL).
  • Describe scientific evidence which supports or refutes the idea of man-made global warming.
  • Distinguish between opinion and evidence based statements in the context of the global warming debate.
  • Explain how it is possible to have good agreement between scientists about the greenhouse effect, but disagreement about whether human activity is affecting global warming. (HL)
P2d Fuels for power
  • Recall that fuels release energy as heat.
  1. Recall the common fuels used in power stations:
    • fossil fuels
    • renewable biomass - wood, straw and manure
    • nuclear fuels - uranium and sometimes plutonium
  • Recall that transformers can be used to increase or decrease voltage.
  • Recall that the unit of power is the watt or kilowatt.
  1. Interpret data to show that the cost of using expensive electrical appliances depends on:
    • power rating in watts and kilowatts
    • the length of time it is switched on.
  1. Calculate the power rating of an appliance using the equation:
    • power = voltage × current
  • Describe and evaluate the advantages and disadvantages of different energy sources; availability, risks and environmental impact.
  1. Calculate the power rating of an appliance using the equation, including conversion of power between watts and kilowatts:
    • power = voltage × current
  • State that the unit of electrical energy supplied is the kilowatt hour.
  1. Calculate the number of kilowatt hours given the:
    • power in kilowatts
    • time in hours.
  • Use the equation:   energy supplied = power × time
  • Calculate the cost of energy supplied.
  • Use and manipulate the equation:   power = voltage × current (HL)
  • Use the kilowatt hour as a measure of the energy supplied. (HL)
  1. Use the equation:  energy supplied = power × time   to calculate (HL):
    • power in kW or W
    • time in hours.
  • Describe the advantages and disadvantages (for consumers and producers) of using off-peak electricity in the home.
  1. Explain why transformers are used in the National Grid to increase the voltage:
    • electrical energy is transmitted at high voltage to reduce energy waste and costs.
  • Explain how, for a given power transmission, an increased voltage reduces current, so decreasing energy waste by reducing heating of cables. (HL)
P2e: Nuclear radiations
  1. Recognise examples where nuclear radiation can be beneficial or harmful:
    • state one example of a beneficial use
    • harmful effect: damages living cells/causes cancer.
  • Understand that radioactive materials give out nuclear radiation over time.
  1. Recall the three types of nuclear radiation:
    • alpha - helium nuclei
    • beta - electrons
    • gamma
  • Understand that nuclear radiation causes ionisation and this is potentially harmful.
  1. Describe how to handle radioactive materials safely:
    • protective clothing
    • tongs / keep your distance
    • short exposure time
    • shielded and labelled storage.
  1. Describe waste from nuclear power as:
    • radioactive
    • harmful
    • not causing global warming
  1. Describe examples of beneficial uses of radiation:
    • alpha - smoke detectors
    • beta - some tracers and paper thickness gauges
    • gamma - treating cancer, non-destructive testing,tracers and sterilising equipment
  1. Describe the relative penetrating power of alpha, beta and gamma:
    • alpha stopped by a few sheets of paper
    • beta stopped by a few mm of aluminium
    • gamma mostly stopped by a few cm of lead.
  • Understand that nuclear radiation can form positive ions when electrons are lost from atoms.
  • Understand that nuclear radiation can form negative ions when electrons are gained by atoms.
  • Interpret data and describe experiments that show how alpha, beta and gamma can be identified by their relative penetrating powers. (HL)
  • Understand that ionisation can initiate chemical reactions. (HL)
  • Explain how ionisation can damage human cells. (HL)
  • Recall that uranium is a non-renewable resource.
  1. Recall that plutonium:
    • is a waste product from nuclear reactors
    • can be used to make nuclear bombs
  1. Describe some ways of disposing of radioactive waste eg:
    • low level waste in land-fill sites
    • encased in glass and left underground
    • reprocessed
  • Describe the advantages and disadvantages of nuclear power. (HL)

  1. Explain the problems of dealing with radioactive waste (HL):
    • remains radioactive for a long time
    • terrorist risk
    • must be kept out of groundwater
    • acceptable radioactivity level may change over time
P2f: Exploring our Solar System
  • Identify the relative positions of the Earth, Sun and planets (includes the order of the planets).
  1. Recall that the Universe consists of:
    • stars and planets
    • comets and meteors
    • black holes
    • large groups of stars called galaxies.
  • Explain why stars give off their own light and can be seen or detected even though they are far away.
  • Recall that radio signals take a long time to travel through the Solar System.
  • Compare the resources needed by manned and unmanned spacecraft.
  • Describe why unmanned spacecraft are sent into space.
  • Recall the relative sizes and nature of planets, stars, comets, meteors, galaxies and black holes.
  • Recall that circular motion requires a centripetal force. (HL)
  • Understand that gravitational attraction provides the centripetal force for orbital motion.
  • Describe a light-year as the distance light travels in a year.
  • Describe some of the difficulties of manned space travel between planets.
  • Explain why a light-year is a useful unit for measuring very large distances in space. (HL)
  • Recall that unmanned spacecraft can withstand conditions that are lethal to humans.
  1. Compare how information from space is returned to Earth from different distances:
    • distant planets require data to be sent back
    • nearby samples can be brought back to Earth for analysis.
  • Explain the advantages and disadvantages of using unmanned spacecraft to explore the Solar System. (HL)
P2g: Threats to Earth
  • Understand that the Moon may be the remains of a planet which collided with the Earth billions of years ago.
  • Recall that large asteroids have collided with the Earth in the past.
  • Recall that asteroids are rocks.
  1. Describe some of the consequences of a collision with a large asteroid:
    • crater
    • ejection of hot rocks
    • widespread fires
    • sunlight blocked by dust
    • climate change
    • species extinction
  1. Describe the make up of a comet:
    • made from ice and dust
    • has a tail formed from a trail of debris.
  • Describe a Near Earth Object (NEO) as an asteroid or comet on a possible collision course with Earth.
  • Describe how NEOs may be seen.
  1. Describe how a collision between two planets can result in an Earth-Moon system:
    • the planets collide
    • their iron cores merge to form the core of the Earth
    • less dense material orbits as the Moon
  • Discuss the evidence for the Earth-Moon system as the result of a collision between two planets. (HL)
  1. Describe asteroids:
    • as being left over from the formation of the Solar System
    • as being in orbit between Mars and Jupiter.
  1. Describe some of the evidence for past asteroid collisions:
    • layers of unusual elements in rocks
    • sudden changes in fossil numbers between adjacent layers of rock
  1. Explain why the asteroid belt is between Mars and Jupiter (HL):
    • the gravitational attraction of Jupiter disrupts the formation of a planet.
  1. Describe comets:
    • as having highly elliptical orbits
    • as coming from objects orbiting the Sun far beyond the planets.
  • Describe how the speed of a comet changes as it approaches a star.
  • Explain in terms of changing gravitational attraction, why the speed of a comet changes as it approaches a star (HL)
  • Describe how observations of NEOs can be used to determine their trajectories.
  • Explain why it is difficult to observe NEOs.
  1. Suggest and discuss possible actions which could be taken to reduce the threat of NEOs (HL):
    • surveys by telescope
    • monitoring by satellites
    • detection by explosions (when they are distant enough from Earth)
P2h Big Bang
  1. Describe some ideas about the Big Bang theory for the origin of the Universe:
    • started with an explosion
    • the Universe is still expanding.
  1. Recall that stars:
    • have a finite life'
    • start as a huge gas cloud
    • are different sizes.
  • Understand why not even light can escape from black holes.
  • Recognise that the accepted models of the size and shape of the Universe have changed over time.
  • Describe and recognise the Ptolemaic and Copernican models of the Universe, and describe how they differ from each other and the modern day model.
  1. Recall that:
    • most galaxies are moving away from us
    • distant galaxies are moving away more quickly
    • microwave radiation is received from all parts of the Universe
  1. Explain how the Big Bang theory accounts for (HL):
    • light from other galaxies shifting to the red end of the spectrum
    • more distant galaxies generally showing greater red shift
    • estimating the age and starting point of the Universe.
  1. Describe the end of the 'life cycle' of a small star:
    • red giant
    • planetary nebula
    • white dwarf.
  1. Describe the end of the 'life cycle' of a large star:
    • red supergiant
    • supernova
    • neutron star or black hole (for massive stars).
  1. Describe the life history of a star: (HL)
    • interstellar gas cloud
    • gravitational collapse producing a proto star
    • thermonuclear fusion
    • long period of normal life (main sequence)
    • end depends on mass of star.
  1. Explain the properties of a black hole (HL):
    • large mass, small volume and high density
    • strong gravitational attraction due to the large mass.
  • Describe the evidence or observations that caused Copernicus and Galileo to develop new scientific models of the Universe, and explain how technological advances contributed to the new models.
  • Explain why the theories of the Copernicus and Galileo models were considered controversial when they were announced, and were not widely adopted until many years had passed. (HL)