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 Form 4 Physics: Electromagnetic spectrum online video lessons

Applications of electromagnetic radiation

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Answer Text:
Applications of electromagnetic radiation
1. Radio waves – they are used in radio, TV and cellular mobile communications.
-Used in military communications (satellite imagery) to form an image of the ground even when there are clouds.
2. Microwaves - used in radar communications by giving direction and distance.
-Used in speed guns by the police to detect over speeding.
-Used in microwave ovens to warm food. The food becomes warm by absorbing energy.
-Used reliably for communication (telephone and computer data).
3. Infra-red radiation - used to produce images of hot objects through the colours
-Produced by the amount of heat dissipated by an object.
-Images produced by satellites give important information on vegetation cover in all areas of the globe. They can also detect fires.
-They are used in hospitals to detect illnesses (diagnosis)
-Used in warfare missiles and burglar alarm systems
-Used in green houses to grow crops
4. Visible light - used by plants in remote sensing and humans in the identification of things
-Used by plants in the process of photosynthesis
5. Ultra-violet (UV) radiation – used to make reflective materials which absorb light and re-emit it as visible light.
-Used in banks to detect fake currency
6. X-rays - used in hospitals to detect fractures, broken bones and in treatment of cancer (radiotherapy).
-Used to detect foreign materials in the body i.e. metals
-Used to detect invisible cracks in metal castings and welding joints
7. Gamma rays - used to sterilize medical instruments
-Used to kill weevils in grain
-Used to take photographs same way like X-rays.