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Thread: The Light Trouble that's Hard

  1. #1 The Light Trouble that's Hard 
    Forum Freshman monaro_waky's Avatar
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    Hi guys, i was wondering why total internal reflection occurs. I understand all the formula's and so on but how does it occur???? :P
    Thanks


    There are no such things as applied sciences, only applications of science.
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  3. #2  
    Forum Freshman Keith's Avatar
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    It occurs because the light enters a substance and refracts but cannot escape the substance because the angle of incidence is no longer greater than the critical angle.


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    Forum Senior anand_kapadia's Avatar
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    Quote Originally Posted by Keith
    It occurs because the light enters a substance and refracts but cannot escape the substance because the angle of incidence is no longer greater than the critical angle.
    For total internal refraction angle of incidence should be greater than critical angle not less. The light rays should also pass from denser to rarer medium.
    We know that when rays travel from denser mediun to rarer medium they bend away from the normal and so for an angle of inciidence the angle of refraction would be 90 degree this angle is critical angle and when the angle of incidence is more than the critical angle the rays would come back in the same medium. this phenomenon is called total internal reflection.
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    Forum Freshman Keith's Avatar
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    Ehh, its been too long since I've taken physics.
    http://img216.imageshack.us/img216/6164/thinghl2.jpg
    "We make our world significant by the courage of our questions and by the depth of our answers." -Carl Sagan
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  6. #5  
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    Check out evanescent waves.

    http://en.wikipedia.org/wiki/Evanescent_wave
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  7. #6  
    Forum Freshman Keith's Avatar
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    I don't understand why it has to be a near-field wave? Doesn't light react the same regardless of the distance?

    I took a non-calculus based physics course in tenth grade. We really didn't learn anything I realize now. Next year I'll be taking the AP Physics course which is a College Board thing as I'm sure a few of you know. So I'll be asking tons of questions during that I'm sure judging on how much I remember.
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