Contents
Key Stage 4
Meaning
Infrared are the third lowest frequency and third longest wavelength electromagnetic waves.
About Infra-red
- Infra-red is a transverse waves.
- Infra-red can travel through a vacuum as well as through gases in the Earth's atmosphere.
- The speed of infra-red through a vacuum is 300,000,000m/s.
As a wave infra-reds can be:
- Transmitted - Infra-reds can pass through a medium.
- Absorbed - The energy transferred by infra-red can be taken in by certain materials, particularly dark coloured materials.
- Reflected - Infra-red can bounce off an interface between two media, particularly the surface of a shiny metal.
- Refracted - Infra-red can change direction when they cross the interface between two media.
Unique Properties
Applications
- Different frequencies of infra-red have different applications.
- Infra-red is used in remote controls and night vision because it is invisible to the human eye but can be transmited through the air without being absorbed.
- Infra-red can be used in thermal imaging because objects emit infra-red radiation due to their temperature. The higher the temperature the more infra-red they emit.
- Infra-red can be used to cook food because it can cause atoms and molecules to vibrate, heating the food.