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Is light a physical item ?

  1. Mar 28, 2010 #1
    Hi,

    I've just been thinking (saw another thread about light).

    Is light a physical item (Ie a brick..- Though on a atomic level)..

    what causes light to go "fast", & as it hits us, why aren't we crushed with all the weight ?
    (or is light weightless ?? )

    as light doesn't pass through things (IE a thick piece of paper), does light just stop travelling & cease to exist (after lighting up the object being hit)...

    what happens to the atoms making up the light after the light stops / ends. ?

    I guess some scientific paper has already been written about the above questions....
     
  2. jcsd
  3. Mar 29, 2010 #2
    To begin with, study Electromagnetism.
     
  4. Mar 29, 2010 #3
    light has no mass , but it has energy and momentum and a gravitational field .
     
  5. Mar 29, 2010 #4

    Fredrik

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    The term "physical" isn't really well-defined, or useful.

    Photons have momentum, and it's transferred to you when it hits you. If you could produce truly absurd amounts of light, it would cause a significant pressure.

    You could say that. The light gets absorbed.

    Light isn't made of atoms. If you mean the atoms that interacts with the light, three things can happen: a) An electron is emitted by the atom, b) An electron moves up to a higher energy level. It will sooner or later fall back down, and when that happens, light is emitted so that energy is conserved, c) the atom gets a different momentum (the total momentum must be conserved). A photon with really absurd amounts of energy (an absurdly short wavelength) could do other things, like smash the nucleus to pieces, but that probably hasn't happened since some small fraction of a second after the big bang.

    Yes. :smile:
     
  6. Mar 29, 2010 #5
    Most people actually get confused when they come across the study of the DUAL NATURE OF LIGHT.Light is actually all about photons.

    Now as you meant to be BLOWN AWAY by the intensity of light :p
    consider the wavelength of light, you will get your anwer yourself.

    Light is sometimes a very astonishing thing to think about !!
    :)
     
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