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

AI Thread Summary
The discussion revolves around determining the actual angle of refraction from water, with the apparent angle given as 53 degrees. The correct actual angle is identified as 37 degrees, which is derived from the relationship that the sum of the angles of incidence and refraction equals 90 degrees. The angle from the horizontal line (water surface) to the light ray is crucial for understanding this relationship. Participants emphasize the importance of visualizing the angles in the provided diagram to clarify the concepts of incidence and refraction. The discussion highlights the geometric principles underlying the refraction of light at the water's surface.
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.
 
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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?
 
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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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