Paper 1

Cards (100)

  • Energy Stores
    1) Elastic potential
    2) Gravitational potential
    3) Thermal
    4) Electrostatic
    5) Nuclear
    6) Chemical
    7) Kinetic
    8) Magnetic
    9) Light
    10) Sound
  • How is energy transferred?
    1) Mechanically - force doing work
    2) Electrically - work done by moving charges
    3) Heating/Radiation - light, sound
  • How can work be done?
    When a current flows or by a force moving an object
  • Kinetic energy formula
    E=1/2mv²
    Kinetic energy(J) = 0.5 x mass(kg) x speed²(m/s)
  • Gravitational potential energy formula
    E=mgh
    G.P.E(J) = mass(kg) x gravitational field strength (N/kg) x height (m)
  • What happens when an object falls and there's no air resistance?
    Energy lost from the g.p.e store = energy gained in the kinetic energy store
  • What does air resistance do when acting against falling objects?
    It causes some energy to be transferred to other energy stores e.g. the thermal energy stores of the object and the surroundings
  • Elastic potential energy formula
    E=1/2ke²
    E.P.E(J) = 0.5 x spring constant(N/m) x extension²(m)
  • What is SHC?
    The amount of energy needed to raise the temperature of 1kg of a substance by 1°C
  • SHC formula
    E=mcθ
    Change in thermal energy(J) = mass(kg) x SHC(J/kg/°C) x temperature change(°C)
  • What is the conservation of energy principle?
    Energy can be transferred usefully, or stored or dissipated (wasted energy), but can never be created or destroyed
  • What is power?
    The rate of energy transfer, or the rate of doing work
  • What is 1W equal to?
    1J of energy transferred per second
  • Power Equation 1
    E=Pt
    Energy transferred(J) = power(W) x time(s)
  • Power Equation 2
    W=Pt
    Work done(J) = power(W) x time(s)
  • What is conduction?
    The process where vibrating particles transfer energy to neighbouring particles
    Energy is transferred to thermal stores of the object - this energy is shared across the kinetic energy stores
  • What is thermal conductivity?
    A measure of how quickly energy is transferred through a material via conduction
  • What is convection?
    Where energetic particles move away from hotter to cooler regions
    Energy is transferred to the thermal energy stores of the object and is shared across the kinetic stores
  • What do radiators create?
    Convection currents
  • Convection currents - process
    1) Energy is transferred from the radiator to the nearby air particles by conduction
    2) The air by the radiator becomes warmer and less dense as the particles move quicker
    3) The warm air rises and displaces the cooler air, which is then heated by the radiator
    4) The previously heated air transfers energy to the surroundings - the air cools, becomes denser and sinks
  • What does lubrication do?
    Reduce frictional forces
  • What does insulation do?
    Reduce the rate of energy transfer by heating
  • Thermal insulation techniques
    1) Cavity walls - made up of an inner and outer wall with an air gap in the middle - the air gap reduces the amount of energy transferred by conduction through the walls
    2) Cavity wall insulators - the air gap is filled with foam also reduces energy transfer by convection in the wall cavity
    3) Loft insulation - reduces convection currents being created in lofts
    4) Double-glazed windows - air gap between two sheets of glass that prevent energy transfer by conduction through the windows
    5) Draught excluders - reduce energy transfers by convection around doors and windows
  • How do you improve efficiency?
    1) Lubrication
    2) Insulation
    3) Making objects more streamlined
  • Efficiency - energy transfer equation
    Useful output energy transfer divided by total input energy transfer
  • Efficiency - power equation
    Useful power output divided by total power input
  • Is any device 100% efficienct?
    No
  • Where is wasted energy usually transferred?
    Thermal energy stores
  • How do thick walls prevent energy losses through heating?
    They're made from a material with a low thermal conductivity - the thicker the walls, the lower the thermal conductivity, the slower the rate of energy transfer
  • What objects are usually 100% efficient?
    Electric heaters - all the energy in the electrostatic energy stores is transferred to useful thermal energy stores
  • Fossil fuels (coal, oil, natural gas)
    Non-renewable
    Cause acid rain
    Cause global warming
    Reliable currently - they are finite, so they will run out eventually
    Coal mining ruins the landscape
    Oil spillages cause serious environmental problems
  • Energy resources used for transport
    Petrol and diesel from oil - non-renewable
    Coal (steam trains) - non-renewable
    Bio-fuels - renewable
  • Energy resources used for heating
    Natural gas - non-renewable
    Coal - non-renewable
    Electric heaters - non-renewable
    Geothermal - renewable
    Solar water heaters - renewable
    Bio-fuels - renewable
  • Wind Power
    Renewable
    Doesn't cause global warming
    Doesn't cause acid rain
    No pollution
    No permanent damage to the landscape
    Free - initial costs are high
    Very noisy
    Spoil the view
    Not always reliable
  • Solar Power
    Renewable
    Doesn't cause acid rain
    Doesn't cause global warming
    No pollution
    Free - solar panels are expensive though
    Not always reliable
  • Geothermal Power
    Renewable
    Doesn't cause acid rain
    Doesn't cause global warming
    Free
    Very little damage to the environment
    Not very reliable - can only happen in certain places and there aren't very many of them
  • Hydroelectric Power
    Renewable
    Reliable
    Doesn't cause acid rain
    Doesn't cause global warming
    No pollution
    Provides an immediate response to high demand
    Free - initial cost is high
    Big impact on environment and possible loss of habitat
  • Wave Power
    Renewable
    Doesn't cause acid rain
    Doesn't cause global warming
    Free - initial costs are high
    Not always reliable - waves die out when the wind drops
    Disturbs the seabed and habitats of marine wildlife
    Spoils the view
    Hazard to boats
  • Tidal Power
    Renewable
    Reliable
    Doesn't cause acid rain
    Doesn't cause global warming
    No pollution
    Free - initial costs are moderately high
    Spoils the view
    Alters the habitats of wildlife
  • Bio-fuels
    Renewable
    Reliable
    Doesn't cause acid rain
    Carbon neutral
    Free
    Can cause global warming
    Loss of natural habitat from destruction of forests
    Cannot respond to immediate energy demands