Radiation and surfaces Flashcards
Why does an electric fire usually have a shiny panel behind the heating element?
Because shiny surfaces are bad at absorbing infared radiation and emitting it
Why does your house still lose heat even if it is well insulated?
Because cavity wall insulation can prevent heat loss by conduction and convection, but not by radiation, as it can travel through a vacuum, like light.
What is infared radiation?
The transfer of energy by electromagnetic waves
It does not need a medium to travel through.
What part of a cooker emits infared radiation?
The electric cooker ring
What is a thermogram?
A picture taken using a special camera which is sensitive to infared radiation but not visible light.
How can you increase the amount of energy radiated from an onject?
Increase the temperature
What natural object can objects absorb radiation from?
The sun
What can affect how much energy an object absorbs & how?
The surface:
>A dark matt surface is good at absorbing infared radiation & good at emitting it
>A light- coloured or shiny surface is bad at absorbing infared radiation & bad at emitting it
