infrared

• 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
• What is the order of infrared emission from the surfaces?

  Matte black, shiny black, white, shiny metallic
• What is the limitation of using a thermometer instead of an infrared detector?

  The thermometer has lower resolution than the detector
• What is the resolution of a thermometer?

  Smallest change that can be detected
• How do you measure the absorbance of infrared by different surfaces?

  Use an infrared heater and metal plates
• What happens to the temperature of the metal plates when the infrared heater is switched on?

  The temperature increases as they absorb infrared
• What indicates that the matte black plate absorbs more infrared?

  The drawn pin falls off the matte black plate first
• What is the effect of shiny metallic surfaces on infrared radiation?

  They tend to reflect infrared radiation