Optics [refraction] - What is the actual angle from the surface of the water

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Homework Help Overview

The discussion revolves around a problem in optics, specifically concerning the refraction of light at the interface between air and water. The original poster presents a scenario where the apparent angle of incidence is given as 53 degrees, and they seek to determine the actual angle of refraction from the water's surface.

Discussion Character

  • Exploratory, Assumption checking, Problem interpretation

Approaches and Questions Raised

  • Participants explore the definition of the "actual angle" and its relationship to the apparent angle. Questions arise regarding the geometry involved and the significance of the angles presented in the drawing. Some participants discuss the numerical relationship between the angles and seek clarification on how these angles relate to the concepts of incidence and refraction.

Discussion Status

The discussion is active, with participants providing insights and modifications to the original drawing to clarify the angles involved. There is an ongoing exploration of the relationships between the angles, but no consensus has been reached regarding the reasoning behind the calculations or the definitions of the angles.

Contextual Notes

Participants are working with a visual representation of the problem, which may influence their interpretations. The original poster's mention of a specific answer suggests a potential misunderstanding of the geometry involved, which is being examined through the discussion.

Paulo Serrano
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Homework Statement



[PLAIN]http://img203.imageshack.us/img203/3072/refractiong.jpg

The apparent angle from the water is 53 degrees, but what is the actual angle from the water?

Homework Equations



n1 * sin i = n2 * sin r

The Attempt at a Solution



I think the real problem here is I'm not seeing some basic geometry stuff. The answer is 37 degrees.
 
Last edited by a moderator:
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Which angle in the drawing is "the actual angle from the water"? How is it defined? Does it help to point out the numerological result that 53o+37o=90o?
 
That "actual angle" is the angle from the horizontal line (the water line) and the red line representing the light from the lamp (the one that is smaller than 53 degrees).

And yeah, I guess it makes sense than 90-53=37, but why that is the right answer I do not know.
 
OK, can you find the 53o angle somewhere between the lines you have drawn below the surface of the water? Look at your drawing. The continuation of the lines that form the 53o in air, form what angle on the other side? How is that related to the angle of refraction?
 
Last edited:
To help Kuruman, I modified your picture, showing the angle of incidence (i) and the angle of refraction (r). Look at the drawing, and find the value of r.

ehild
 

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