Solving index of refraction for Total Internal Reflection

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Homework Help Overview

The discussion revolves around calculating the index of refraction in the context of total internal reflection, utilizing Snell's Law and related concepts. Participants are exploring the relationship between angles of incidence and refraction, particularly in scenarios involving critical angles.

Discussion Character

  • Exploratory, Assumption checking, Problem interpretation

Approaches and Questions Raised

  • The original poster attempts to visualize the problem through a diagram and has previously derived a formula for the index of refraction. However, they express uncertainty about the next steps after finding the angle of refraction. Other participants inquire about the angle of incidence and its relationship to total internal reflection, questioning the conditions under which reflection occurs.

Discussion Status

The discussion is ongoing, with participants providing guidance on showing work clearly and exploring the implications of angles involved in refraction and reflection. There is a focus on clarifying the relationship between angles and the critical angle necessary for total internal reflection.

Contextual Notes

Participants are working under the constraints of homework guidelines, which may limit the amount of direct assistance they can provide. There is a noted ambiguity regarding the angles involved and their definitions in the context of total internal reflection.

RaulTheUCSCSlug
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Homework Statement


Screenshot 2015-03-18 at 7.00.08 PM.png


Homework Equations


Snell's Law
n1sin(theta_1)=n2sin(theta_2)
Total Internal Refraction:
sin(theta_c)=(n_2/n_1)

lambda_n=lambda_n

The Attempt at a Solution



So I drew the triangle and this is what I got, and well here is just a picture so far of what I have.
impossibleprobleeem.jpg

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I've done this problem before and got n=(theta)-(arcsin((sin(theta)/n)) and from there I have no idea. But I did a different approach. Any ideas. I've tried differentiating implicitly after that and trying to integrate and just got a huge mess.
 
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Show your work in readable form.
 
ehild said:
Show your work in readable form.
I just wrote down what I know and some equations, I found out the angle of refraction when the laser beam first enters. But I don't know what to do after.
 
Find the angle of incidence at S2.
 
It would be 90 degrees minus the angle of refraction. But doesn't it have to equal the angle at which it internally reflects?
 
RaulTheUCSCSlug said:
It would be 90 degrees minus the angle of refraction. But doesn't it have to equal the angle at which it internally reflects?
Yes, it should be equal or greater than the critical angle, at which internal reflection occurs. But it is not 90°minus the angle of refraction at S1. Give it in terms of theta and the angle of refraction.
 

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