i wanna know the practical application of De Broglie wavelength in the life !!
All of quantum mechanics. If the answer appears too broad, it's really because of the breadth of the question.
Maybe 'electron microscope' (in it's various incarnations): http://en.wikipedia.org/wiki/Electron_microscope is narrowing it down a bit to something that specifically relies on DW.
[ more useful connection here: http://en.wikipedia.org/wiki/Transmission_electron_microscope] [Broken]
Well, it explains how you are able to exist! If electrons could not form stationary wave states around the nucleus, then there would be no such entitles known as atoms to begin with.
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