GCSE Physics

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GCSE Physics
2012-04-02 11:26:26
transfer energy heating factors that affect rate which transferred green stuff only

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  1. thermal energy can be transferred from all objects by ....... even thorugh empty space (...)
    • radiation
    • vacuum
  2. thermal radiation can be used in
    • infrared heaters
    • passive infra red devices (PIRs)
    • thermal imaging cameras
  3. an infrared heater is a body with a :
    high temperature which transfers energy a body with a lower temperature through electromagnetic radiation
  4. why do we get warm from an infrared heater
    because our skin and clothes absorb the infrared
  5. why do we feel warm in the sun
    because the infrared radiation that hits your clothes and skin keeps you warm
  6. there are several kinds of infrared heaters . some direct thier light straight into a room or space to create heat on the object it reaches . infrared heaters also differ in fuel sources and construction material . there are propane .... .... and .... heaters .some are ceramic , and there are also portable ones
    • natural gas
    • electric
  7. a passive infrared sensor (PIR sensor) is an electronic device that :
    measures infrafed (IR) light emmited from objects in its field of view
  8. PIR sensors are often used in ..... .... . Motion is detected when and infraed source with one temperature , such as a human , passes in front of an infraed source with another temperature such as a wall .
    motion detectors
  9. we had a radiant heater placed directly in gthe middle of two surfaces , one was a black surface and the other was a shiny surface . we held a coin to each surface with grease .
    the coin fell off the .... surface first showing that the ..... surface was a better absorber of heat than a .... surface
    • black
    • black
    • shiny
  10. dark matt surfaces are good .... (poor ....) of radiation
    light , shiny surfaces are good ..... (poor ....) of radiation
    • absorbers
    • reflectors
    • reflectors
    • absorbers
  11. thermal (infrared) radiation is :
    the transfer of electromagnetic (infrared) waves , particles of matter are not invloved in thermal radiation
  12. all obejects ...... and .... radiation
    • emit
    • absorb
  13. the .... an object the more energy it radiates in a given time
  14. ... ... surfaces are good absorbers and good emiters of radiation
    matt black
  15. ..... ... surfaces are poor absorbers and poor emiters of radiation
    shiny bright
  16. .... ..... are good reflectors of radiation
    shiny bright
  17. in a solid , a liquid and a gas what is the arragnement of particles
    • solid - close together and in aregular pattern
    • liquid - close together but random
    • gas - far apart and random
  18. label the diagram
    • A = sublimation
    • B = melting
    • C = freezing
    • D = evapourating or boiling
    • E = condesing
    • (do not need to no A)
  19. what main factor affects the rate of evapouration and condensation
  20. define conduction
    the transfer of energy by a substance , without the substance moving itself is called conduction
  21. list the following metals in order of thier effectivness of conducting : aluminium , copper , brass , iron
    • copper
    • aluminium
    • brass
    • iron
  22. metals are very .... conductors and .... insulators . non metals are usually ..... conductors and gases are .... conductors
    • good
    • poor
    • poor
    • poor
  23. why are metals good conductors of heat
    because they contain lots of elctrons that can move about freely
  24. when a metal bar is heated at one end , the elctrons at that end .... ... . They .... with other free electons . As a result they .... energy from the hot end of a metal . the free electrons also .... with the atoms and make them .... more
    • move faster
    • collide
    • transfer
    • collide
    • vibrate
  25. define convection
    liquids and gases can flow and so can carry energyf rom places where the temperatrue is higher to places where the temperature is lower . transfer of energy by liquids or gases moving in this way is called convection
  26. convection currents occur in ... and ... because thier particles move ... .... when they are hot causing the liquid or gas to .... . when particles move apart they make a fluid less ... . warm regions are then less ... than cold regions . the warm fluids .... through the colder ones and colder fluids replace the warmer ones which have risen
    • liquids
    • gases
    • more freely
    • expand
    • dense
    • dense
    • rise