Infrared Radiation (Oxford AQA IGCSE Physics)

Infrared Radiation

• All objects emit and absorb infrared radiation

• The hotter an object is, the more infrared radiation it radiates in a given time

• The colour of an object, and whether its surface is matt or shiny, affects how good it is at emitting and absorbing infrared radiation

  • Dark, matt surfaces are good absorbers and good emitters of infrared radiation

  • Light, shiny surfaces are poor absorbers and poor emitters of infrared radiation

  • Light, shiny surfaces are good reflectors of infrared radiation

Emission and absorption of infrared radiation

• Black cars get much hotter than white cars in the summer because black objects are good absorbers of infrared radiation

• However, a black car will cool down much faster than a white car at the same temperature because black objects are also good emitters of infrared radiation