Point source of light beneath water.

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SUMMARY

A point source of light located 245.0 cm beneath the surface of water emits light isotropically. The index of refraction for water is 1.33, which results in a light velocity of 2.3E8 m/s as it approaches the surface. To determine the diameter of the circle through which light emerges, one must apply the principles of total internal reflection, which restricts the angles at which light can escape the water. The calculation involves understanding the critical angle and using trigonometric relationships to find the diameter at the water's surface.

PREREQUISITES
  • Understanding of Snell's Law and refraction
  • Knowledge of total internal reflection concepts
  • Familiarity with trigonometric functions and their applications
  • Basic principles of light propagation in different media
NEXT STEPS
  • Study Snell's Law and its application in optical physics
  • Learn about total internal reflection and its critical angle calculations
  • Explore trigonometric relationships in optics, particularly in relation to light paths
  • Investigate the effects of different indices of refraction on light behavior
USEFUL FOR

Students in physics, optical engineers, and anyone interested in the behavior of light in different mediums, particularly in understanding refraction and reflection phenomena.

Beeza
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A point source of light is 245.0 cm below the surface of a body of water. Find the diameter of the circle at the surface through which light emerges from the water.


Can someone give me a push start as to how to approach this problem? I can't figure it out for the life of me.

I know that v=c/n, and using 1.33 at the index of refraction of water, I can find the velocity of the light as it reaches the surface is 2.3E8m/s. The point source will emit light isotropically in all directions, and I have the distance to the surface... but for the life of me I can't find how to relate this to the diameter of the circle it will leave on the surface.
 
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Does your text cover "total internal reflection"? That's the reason why light that is angled way out to the side won't make it out of the water...
 
Thank You. I am such a bonehead sometimes.
 

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