Snell's Law Application Homework Problem

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SUMMARY

This discussion focuses on applying Snell's Law to analyze the behavior of a light ray with a wavelength of 400nm as it interacts with a crystal. The index of refraction for the crystal is calculated to be 1.682725, while the surrounding air has an index of approximately 1. The light ray, incident perpendicular to the bottom face of the crystal, will experience partial reflection and refraction at the interface. The discussion emphasizes the importance of understanding the paths of both transmitted and reflected rays, as well as the implications of Snell's Law in predicting these paths.

PREREQUISITES
  • Understanding of Snell's Law and its mathematical formulation
  • Familiarity with the concept of index of refraction
  • Basic knowledge of light behavior at interfaces
  • Ability to interpret and analyze light ray diagrams
NEXT STEPS
  • Study the derivation and applications of Snell's Law in optics
  • Learn about the principles of reflection and refraction at boundaries
  • Explore the concept of total internal reflection and its conditions
  • Investigate the effects of wavelength on the index of refraction in different materials
USEFUL FOR

Students studying optics, physics educators, and anyone interested in understanding the behavior of light in different media, particularly in relation to Snell's Law and crystal optics.

PropulsionMan
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Homework Statement



snellslaw_zps1120239d.png


I apologize for not utilizing built-in Latex, I'll have to work with that a little more.Question statement: Explain the paths, both transmitted and reflected, that a light ray of 400nm would take if it was incident perpendicular to the bottom face ofo the crystal. If the light was in the shape below (just an arrow shown in the positive Y-direction of an X-Y coordinate plane), what would the relative orientation be when it leaves the crystal.

Homework Equations



(sin(θ1))*(n1) = (sin(θ2))*(n2) = λ1sin(θ2) = λ2sin(θ1)

The Attempt at a Solution



To be honest, I'm trying to figure out where to start with this one. I've used the provided equation and calculated n to be 1.682725, however I don't know if that corresponds to the incident or refracted side of the light, and if the light is coming in through the bottom face at the center, I'm not sure if I should consider the transmission through the assumed air medium before it hits the crystal. I could very well be overthinking it, but I'd love some direction.

Additionally, I understand that Snell's Law has the ability to predict how these light rays will trace through mediums based on wanting to take the path that's quickest through the medium. I don't know if I have to consider light that's lost at the top surface though--will some light exit the crystal?
 
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PropulsionMan said:

Homework Statement



[ URL=http://s1320.photobucket.com/user/P_Brooks_Sargent/media/snellslaw_zps1120239d.png.html][ IMG]http://i1320.photobucket.com/albums/u536/P_Brooks_Sargent/snellslaw_zps1120239d.png[/URL]

I apologize for not utilizing built-in Latex, I'll have to work with that a little more.

Question statement: Explain the paths, both transmitted and reflected, that a light ray of 400nm would take if it was incident perpendicular to the bottom face ofo the crystal. If the light was in the shape below (just an arrow shown in the positive Y-direction of an X-Y coordinate plane), what would the relative orientation be when it leaves the crystal.

Homework Equations



(sin(θ1))*(n1) = (sin(θ2))*(n2) = λ1sin(θ2) = λ2sin(θ1)
You should not have that middle equal sign.

(sin(θ1))*(n1) = (sin(θ2))*(n2)

λ1sin(θ2) = λ2sin(θ1)

The Attempt at a Solution



To be honest, I'm trying to figure out where to start with this one.
Start with the incident ray approaching the crystal from below.

A fraction of the intensity will be reflected at the surface. This is a reflected ray.

A fraction will pass into the crystal, its direction determined by Snell's Law. This is a refracted ray.
I've used the provided equation and calculated n to be 1.682725, however I don't know if that corresponds to the incident or refracted side of the light, and if the light is coming in through the bottom face at the center, I'm not sure if I should consider the transmission through the assumed air medium before it hits the crystal. I could very well be overthinking it, but I'd love some direction.
Whenever the ray strikes a surface, it will be partially reflected and partially refracted -- unless Snell's Law says the refracted beam is impossible -- this may well be a part of this exercise.

I would assume that the crystal is surrounded by air, the index of refraction of which is very close to 1.

In applying Snell's Law: Any ray approaching a surface is the incident ray. Any ray passing into the neighboring medium is the refracted ray.

Use ncrystal = 1.682725 and nair = 1 appropriately .
Additionally, I understand that Snell's Law has the ability to predict how these light rays will trace through mediums based on wanting to take the path that's quickest through the medium. I don't know if I have to consider light that's lost at the top surface though--will some light exit the crystal?
I doubt that you are expected to use Fermat's Principle, the principle of least time.
 

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The book claims the answer is that all the magnitudes are the same because "the gravitational force on the penguin is the same". I'm having trouble understanding this. I thought the buoyant force was equal to the weight of the fluid displaced. Weight depends on mass which depends on density. Therefore, due to the differing densities the buoyant force will be different in each case? Is this incorrect?

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