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How double glasses window reflect ?

  1. Jul 7, 2011 #1
    Today when i was travelling in train(from my study center to home) i found a common but unexplained thing that is a little reflection can be seen on Glass window of train when it is underground or there is any wall behind the windows BUT when there is no window(ex when it is in station there is a lot of light) then i can't see any kind of reflection in window (or very very little reflection). I had read very little on Optics like Lens maker formula etc. I try to explain this during my 30 minute journey but i can't so i want to know it's answer from you why there is reflection in glass window.why this glass window was reflecting when it was underground. This glass window was double(one plate of glass after other as i see) i think because they(manufacturer of train) do this to don't make it hot due to sun in summer/ keep train cool with it's AC.One thing i also want to say that there a lot of lights inside train as a source of light for reflection.

    How I explain it.
    first explanation::-> This reflection happen due to reflection backward wall. Limitation wall did not reflect.
    second explanation ::-> Double glass window of train reflect light rays every time but i can see them only at that time when there is any obstacle that does not overcome the intensity of light of reflected rays by glass window in case of stations there is light entering inside train which overcome the intensity of reflected light by glass window but when it is underground no light enter externally so i can see reflection of persons inside train. this idea has recently came in mind is it correct? Or there is any other explanation for this?

    there is no double glass window in my house or nearby to experiment so you tell me.
    Last edited: Jul 7, 2011
  2. jcsd
  3. Jul 7, 2011 #2

    Andrew Mason

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    It looks like you have the right idea. Glass will always reflect part of the light that strikes it and will always transmit some of that incident light.

    If there is no light coming from outside the train, the only light you will see from the window will be light from inside reflected back to you. If there is a lot of light outside, the light coming from the window will consist mostly of outside light transmitted through the window with a relatively small amount of light reflected back from the inside, so the reflected light will be hard to distinguish.

  4. Jul 8, 2011 #3
    :smile:Thanks Andrew.:smile:

    I was excepting that there will many replies for this question but Here is only 1.:zzz:
    I need more replies to confirm it 100% so please post your opinion guys!.:approve:
  5. Jul 8, 2011 #4
  6. Jul 8, 2011 #5
    thanks andrew and Gordianus for their answer now i am 100% confirmed that my explanation is correct.
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