Wireless Charging Of Mobile Phones using Microwaves|PPT|PDF|DOC|Presentation|

   
To start with, to know what a spectrum is: when white light is shone through a prism it is separated out into all the colors of the rainbow; this is the visible spectrum. So white light is a mixture of all colors .Black is NOT a color; it is what you get when all the light is taken away. Some physicists pretend that light consists of tiny particles which they call photons.



 They travel at the speed of light (what surprise). The speed of light is about 300,000,000 meters per second. When they hit something they might bounce off, go right through or get absorbed. What happens depends a bit on how much energy they have.
 If they bounce off something and then go into your eye you will "see" the thing they have bounced off. Some things like glass and Perspex will let them go through; these materials are transparent.

Black objects absorb the photons so you should not be able to see black things: you will have to think about this one. These poor old physicists get a little bit confused when they try to explain why some photons go through a leaf, some are reflected, and some are absorbed. They say that it is because they have different amounts of energy. Other physicists pretend that light is made of waves.



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