Solving index of refraction for Total Internal Reflection

In summary, the conversation discusses the use of Snell's Law and Total Internal Refraction in finding the angle of incidence at S2 in a triangle. The participant has found the angle of refraction at S1 using the equations n1sin(theta_1)=n2sin(theta_2) and sin(theta_c)=(n_2/n_1), but is unsure of what to do next. They suggest using a different approach and mention differentiating and integrating, but have not found a solution yet. They also mention that the angle of incidence at S2 should be equal or greater than the critical angle for internal reflection, but it is not equal to 90° minus the angle of refraction at S1.
  • #1
RaulTheUCSCSlug
Gold Member
179
27

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

[/B]

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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  • #2
Show your work in readable form.
 
  • #3
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.
 
  • #4
Find the angle of incidence at S2.
 
  • #5
It would be 90 degrees minus the angle of refraction. But doesn't it have to equal the angle at which it internally reflects?
 
  • #6
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.
 

1. What is total internal reflection?

Total internal reflection occurs when a ray of light traveling through a medium reaches the boundary of a different medium and is completely reflected back into the original medium, instead of being refracted into the second medium. This phenomenon only occurs when the angle of incidence is greater than the critical angle for the two mediums.

2. How is the index of refraction calculated?

The index of refraction is calculated by dividing the speed of light in a vacuum by the speed of light in the medium. It is denoted by the symbol "n" and is a dimensionless quantity.

3. What is the relationship between the index of refraction and total internal reflection?

The index of refraction plays a crucial role in total internal reflection. It determines the critical angle at which total internal reflection occurs. A higher index of refraction means a smaller critical angle, making it easier for total internal reflection to occur.

4. What are some real-life applications of total internal reflection?

Total internal reflection has many practical applications, such as in fiber optics, where light is transmitted through optical fibers using total internal reflection. It is also used in binoculars, prisms, and reflectors in traffic signs.

5. How can the index of refraction be solved for in the case of total internal reflection?

The index of refraction can be solved for by using Snell's Law, which states that the ratio of the sines of the angles of incidence and refraction is equal to the ratio of the indices of refraction for the two mediums. By setting the angle of refraction to 90 degrees, the critical angle can be calculated, and then the index of refraction can be solved for.

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