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

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Homework Help Overview

The discussion revolves around calculating the fraction of light reflected from the air-water interface using the reflection coefficient formula. Participants are exploring the implications of their calculations and interpretations of the results.

Discussion Character

  • Mathematical reasoning, Assumption checking

Approaches and Questions Raised

  • Participants present different calculations for the reflection coefficient, questioning the accuracy of their results and interpretations. There is a focus on the values of the refractive indices and the squaring of the result in the formula.

Discussion Status

The discussion is active, with participants providing differing results and interpretations of the reflection coefficient. Some participants confirm the 25% reflection, while others suggest a much lower value, indicating ongoing exploration of the calculations.

Contextual Notes

There are discrepancies in the calculations presented, with some participants suggesting different values for the reflection coefficient based on their interpretations of the formula and the refractive indices used.

stunner5000pt
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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:
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stunner5000pt said:
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?

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

EDIT: Check your calculation. I get R=0.02, So 2% is reflected.
 
Last edited:
learningphysics said:
Yes. 25% is reflected. 75% is transmitted (refracted).
so th fraction would be 1/4 right? Thanks for the help!
 
stunner5000pt said:
so th fraction would be 1/4 right? Thanks for the help!

I get R=0.02
 
As did I. R = .02
 
i think you are forgetting to square it it's (0.33/1.33)^2 = 0.062
 
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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