Which one of the following emits the most infrared radiation?
  • 1 kg of water at 95oC
  • 1 kg of iron at 68oC
  • 1 kg of your body at 37oC
  • 1 kg of crude oil at 72oC
In sunny countries, houses are often painted white. Why?
  • Painting them white lowers the U-value of the walls
  • White paint does not conduct heat
  • White is a good reflector of thermal radiation
  • The white paint reflects the light into the narrow streets which otherwise would be dark
Thermal radiation can only travel through which substances?
  • Solids
  • Liquids
  • Gases
  • Transparent and translucent substances
Put the following in order of best to worst of infrared radiation:Red, dullWhite, shinyBlack, dullRed, shiny
  • 1, 3, 4, 2
  • 2, 4, 1, 3
  • 1, 2, 3, 4
  • 4, 1, 3, 2
Which are the best emitters of thermal radiation?
  • Black, dull surfaces
  • Light coloured dull surfaces
  • Black shiny surfaces
  • Light coloured shiny surfaces
Why are car radiators often painted matt black?
  • So that splashes of engine oil won't show up
  • To make them more efficient
  • To make the car more attractive to buyers
  • It is a legal requirement
Which of the following does use infrared radiation?
  • Security lamps
  • A head torch
  • A remote control for a TV
  • An intruder alarm
In an electric toaster, what methods of heat transfer cook the bread?
  • Mainly radiation with some conduction
  • Mainly conduction and some radiation
  • Conduction and convection only
  • Mainly convection but conduction has a part to play too
Thermal radiation travels at what speed?
  • Very slowly
  • Instantaneously
  • The speed of sound
  • The speed of light
The inside container of a vacuum flask is silvered. Why?
  • To reduce heat loss by radiation
  • To completely prevent heat loss by radiation
  • To reduce heat loss by evaporation
  • To reduce heat loss by condensation
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