Does microwave or infrared radiation have longer wavelengths?

Microwaves have longer wavelengths than infrared waves.

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How do microwave ovens work?

  1. The microwaves are absorbed by the water molecules in the food or object being heated.
  2. This transfers energy to them, which can then be transferred throughout the food or object to heat it.

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Can the microwaves used in satellite communication be absorbed by water molecules? Explain.

No.


If they were absorbed by water molecules they wouldn't be able to pass through the atmosphere.

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What is infrared radiation emitted from? 

Infrared radiation is emitted from all objects that have thermal energy.


The hotter an object is, the more infrared radiation it will emit.

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Give 3 uses of infrared radiation.

  1. In infrared cameras to detect motion or monitor temperature.
  2. To heat food in a toaster or grill.
  3. To heat a room via an electric radiator.

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