Contents
Key Stage 4
Meaning
Infra-red 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.
- Infra-red can be used in fibre optic communication because it is not absorbed by the glass that the fibres are made from and it is reflected internally by the interface between the glass and the air.
Dangers
- Infra-red can cause skin burns because it can cause atoms and molecules to vibrate, heating the material.
References
AQA
- Infrared, pages 200, 206, 209, 210, GCSE Combined Science Trilogy; Physics, CGP, AQA
- Infrared, pages 242, 248, 256-259, GCSE Physics; The Complete 9-1 Course for AQA, CGP, AQA
- Infrared; absorption, page 220, GCSE Physics; Student Book, Collins, AQA
- Infrared; detector, pages 221, 233, GCSE Physics; Student Book, Collins, AQA
- Infrared; emission, page 221, GCSE Physics; Student Book, Collins, AQA
- Infrared; investigating, pages 209, 210, GCSE Combined Science Trilogy; Physics, CGP, AQA
- Infrared; investigating, pages 257, 258, GCSE Physics; The Complete 9-1 Course for AQA, CGP, AQA
- Infrared; radiation, pages 191, 196-7, 213-14, 219-21, 230, 232-5, GCSE Physics; Student Book, Collins, AQA
Edexcel
- Infrared (IR) radiation, pages 280, 320, 340, 341, 346, GCSE Combined Science, Pearson Edexcel
- Infrared radiation, page 127, GCSE Physics, CGP, Edexcel
- Infrared radiation, page 166, GCSE Chemistry, Pearson, Edexcel
- Infrared radiation, pages 38, 72, 73, 78, GCSE Physics, Pearson Edexcel
- Infrared radiation; dangers, page 136, GCSE Physics, CGP, Edexcel
- Infrared radiation; uses, pages 132, 133, GCSE Physics, CGP, Edexcel
- Infrared, pages 168, 170, GCSE Combined Science; The Revision Guide, CGP, Edexcel
- Infrared, pages 43, 46, GCSE Physics; The Revision Guide, CGP, Edexcel