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• What is the main objective of the practical described in the video?

  To investigate infrared radiation absorption and emission
• Why can't the human eye see infrared radiation?


  Infrared radiation is outside the visible spectrum
• What is a Lesley's cube used for?

  To measure infrared emission from surfaces
• What surfaces are present on a Lesley's cube?

  Shiny metallic, white, shiny black, matte black
• How do you ensure repeatable measurements in the experiment?

  Keep the same distance between the cube and detector
• Which surface emits the most infrared radiation?

  Matte black surface
• Which surface emits the least infrared radiation?

  Shiny metallic surface
• What can be used if an infrared detector is unavailable?

  A thermometer with a black-painted bulb
• What is the resolution of a thermometer compared to an infrared detector?

  The thermometer has lower resolution
• How do you measure the absorbance of infrared by different surfaces?

  Using an infrared heater and metal plates
• What happens to the temperature of the metal plates during the experiment?

  The temperature increases as they absorb infrared
• Which plate does the drawn pin fall off first?

  The matte black plate
• Why do matte black surfaces absorb more infrared than shiny metallic surfaces?


  Matte black surfaces are better absorbers
• What is the effect of shiny metallic surfaces on infrared radiation?

  They tend to reflect infrared radiation
• Where can students find questions related to this practical?

  In the revision workbook linked in the video