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Homework Help: What fraction of light is reflected from the air water interface?

  1. Mar 2, 2005 #1
    What fraction of light is reflected from the air water interface? i.e. How intense is your reflection from a lake?

    since the reflection coefficient is [tex] R = (\frac{n_{2} - n_{1}}{n_{1} + n_{2}})^2 [/tex]

    n1 = 1 and n2 = 1.33 so R = 0.248. I am not sure how to interprete this?

    25% of the light reflects?? is that the appropriate answer?
     
    Last edited: Mar 2, 2005
  2. jcsd
  3. Mar 2, 2005 #2

    learningphysics

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    Yes. 25% is reflected. 75% is transmitted (refracted).

    EDIT: Check your calculation. I get R=0.02, So 2% is reflected.
     
    Last edited: Mar 2, 2005
  4. Mar 2, 2005 #3
    so th fraction would be 1/4 right? Thanks for the help!!
     
  5. Mar 2, 2005 #4

    learningphysics

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    I get R=0.02
     
  6. Mar 2, 2005 #5
    As did I. R = .02
     
  7. Mar 2, 2005 #6
    i think you are forgetting to square it it's (0.33/1.33)^2 = 0.062
     
  8. Mar 2, 2005 #7
    Nope.

    [tex](\frac{1.33-1}{1 + 1.33}) = .1416.....[/tex]

    [tex].1416309^2 = .020059....[/tex]

    I don't see the problem.

    EDIT: You divided by the wrong number...it's 2.33 not 1.33
     
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