Laser Beam and index of refraction

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SUMMARY

The discussion centers on the refraction of a laser beam entering a glass window with a thickness of 10.0 cm and an index of refraction of 1.46 at an angle of 30 degrees from the normal. The correct calculation for the angle of refraction, theta 2, is derived using Snell's Law, which states that n1 * sin(theta1) = n2 * sin(theta2). The correct angle of refraction is 19.24 degrees, not 46.89 degrees as initially calculated. The confusion arose from misapplying the formula, highlighting the importance of correctly identifying the indices of refraction.

PREREQUISITES
  • Understanding of Snell's Law in optics
  • Familiarity with the concept of angle of incidence and angle of refraction
  • Basic knowledge of trigonometric functions
  • Ability to perform calculations involving indices of refraction
NEXT STEPS
  • Study the derivation and applications of Snell's Law in different media
  • Learn about the behavior of light in various materials with different indices of refraction
  • Explore advanced topics in optics, such as total internal reflection
  • Practice problems involving refraction with varying angles and materials
USEFUL FOR

Students in physics or engineering, educators teaching optics, and anyone interested in understanding the principles of light behavior in different mediums.

skibum143
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Homework Statement


A laser beam enters a 10.0cm thick glass window at an angle of 30 degrees from the normal. The index of refraction of the glass is 1.46. At what angle from the normal does the beam travel through the glass?


Homework Equations


sin theta 1 / sin theta 2 = n1 / n2 = v1 / v2

The Attempt at a Solution


sin (30) / sin theta 2 = 1 / 1.46
theta 2= 46.89 degrees

Not sure what I'm doing wrong here? I also tried 90 deg - 46.89 = 43.11 deg but that was also wrong.
 
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skibum143 said:

Homework Equations


sin theta 1 / sin theta 2 = n1 / n2 = v1 / v2

No, sin theta 1 / sin theta 2 = n2 / n1. You can also remember it as n1*sin(theta1)=n2*sin(theta2), which I find easier to use.
 
Ah, I see. Thank you!
 

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