Contents
Key Stage 4
Meaning
Microwaves are the second lowest frequency and second longest wavelength electromagnetic waves.
About Microwaves
- Microwaves are transverse waves.
- Microwaves can travel through a vacuum as well as through gases in the Earth's atmosphere.
- The speed of microwaves through a vacuum is 300,000,000m/s.
As a wave microwaves can be:
- Transmitted - Microwaves can pass through a medium.
- Absorbed - The energy transferred by microwaves can be taken in by certain materials, particularly metals.
- Reflected - Microwaves can bounce off an interface between two media.
- Refracted - Microwaves can change direction when they cross the interface between two media.
Unique Properties
- Microwaves can cause alternating currents in metals.
- Microwaves can cause water molecules to oscillate, heating the water.
Applications
- Microwaves can be used in satellite communication and mobile phone communication because they can be created by alternating current and can cause an alternating current in metals.
- Microwaves can be used for cooking because they cause water molecules and fat molecules to oscillate increasing the temperature of the food.
Dangers
- Microwaves can cause internal heating of living creatures because they are made of water which is heated by microwaves.
References
AQA
- Microwaves, page 79, GCSE Physics; The Revision Guide, CGP, AQA
- Microwaves, pages 193-195, GCSE Physics; Third Edition, Oxford University Press, AQA
- Microwaves, pages 194, 195, 198-9, GCSE Physics, Hodder, AQA
- Microwaves, pages 200, 205, GCSE Combined Science Trilogy; Physics, CGP, AQA
- Microwaves, pages 223, 224, GCSE Combined Science; The Revision Guide, CGP, AQA
- Microwaves, pages 242, 247, GCSE Physics; The Complete 9-1 Course for AQA, CGP, AQA
- Microwaves, pages 261, 267, GCSE Combined Science Trilogy 2, Hodder, AQA
- Microwaves; uses and applications, page 200, GCSE Physics, Hodder, AQA
Edexcel
- Microwaves, page 127, GCSE Physics, CGP, Edexcel
- Microwaves, pages 168-170, GCSE Combined Science; The Revision Guide, CGP, Edexcel
- Microwaves, pages 344, 346, GCSE Combined Science, Pearson Edexcel
- Microwaves, pages 43, 45, 46, GCSE Physics; The Revision Guide, CGP, Edexcel
- Microwaves, pages 76, 78, GCSE Physics, Pearson Edexcel
- Microwaves; dangers, page 136, GCSE Physics, CGP, Edexcel
- Microwaves; uses, pages 131, 133, GCSE Physics, CGP, Edexcel