When can internal reflection be used to find the index of refraction

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Homework Help Overview

The discussion revolves around using internal reflection to determine the index of refraction of a material. Participants are exploring the concept of critical angles and the relationship between the indices of refraction at the boundary of two materials.

Discussion Character

  • Exploratory, Conceptual clarification, Assumption checking

Approaches and Questions Raised

  • Participants are attempting to conceptualize an experiment that utilizes internal reflection to measure the index of refraction. Questions are raised about the dependency of the critical angle on the indices of refraction of the two materials involved.

Discussion Status

There is an ongoing exploration of how to set up the experiment and the mathematical relationships involved. Some participants have provided insights into the critical angle and its calculation, while others are seeking clarification and diagrams to aid understanding.

Contextual Notes

Participants are discussing the need for specific experimental setups and the potential constraints of known indices of refraction for one material in order to determine the unknown index.

Cocoleia
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Homework Statement


I need to describe an experiment in which I would use internal reflection to determine the index of refraction of material

Homework Equations



Snell's law

The Attempt at a Solution


I understand the concept of internal reflection, such as the critical angle etc. I am just unsure of what kind of experiment could let me determine the index of refraction
 
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Cocoleia said:

Homework Statement


I need to describe an experiment in which I would use internal reflection to determine the index of refraction of material

Homework Equations



Snell's law

The Attempt at a Solution


I understand the concept of internal reflection, such as the critical angle etc. I am just unsure of what kind of experiment could let me determine the index of refraction
Can you show us a diagram of the critical angle, and show us the equation you would use to calculate the angle for TIR?
 
And how is that angle dependent on the two indices of refraction of the two materials at the boundary?
 
berkeman said:
And how is that angle dependent on the two indices of refraction of the two materials at the boundary?
Critical angle = inverse sin(nr/ni
Once we reach the critical angle we will have total internal reflection.
 
Cocoleia said:
Critical angle = inverse sin(nr/ni
Once we reach the critical angle we will have total internal reflection.
So if you know the index for the lower index material, and can control the angle of incidence into the boundary, you should be able to determine the unknown index experimentally, right? :smile:
 

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