Solve Water Refraction: Length of Stick's Shadow

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AI Thread Summary
The discussion focuses on calculating the length of the shadow cast by a 1.93-meter tall stick submerged in water, illuminated by sunlight at a 45-degree angle. The user initially attempts to solve the problem using trigonometric functions but arrives at an incorrect shadow length of 1.45 meters. A hint suggests applying Snell's law to determine the angle of refraction for the light entering the water. The correct approach involves finding the refracted angle to accurately calculate the shadow length. Understanding and applying Snell's law is crucial for solving the problem correctly.
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[SOLVED] Water Refraction

Homework Statement



An opaque stick which is d = 1.93 meters tall stands vertically upright on the bottom of a pool of clear water. Parallel rays of sunlight making an angle of 45.0 degrees with the water?s surface illuminate the pool as shown. What is the length of the shadow the stick casts on the bottom of the pool?

Homework Equations



n_{a}=1.00
n_{b}=1.33
stick_in_water.gif


The Attempt at a Solution



So I just took

arctan(\frac{1.33}{1.00})=53.06

And I need the angle that will form a triangle with the rod, so

90-53.06=36.94

Then, since the shadow forms the base of a triangle, I solved for it:

tan(36.94)=\frac{opp}{adj}=\frac{opp}{1.93m}

Adn I got that the shadow equals 1.45 m, which was incorrect. What am I doing wrong?
 
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ttiger2k7 said:
So I just took

arctan(\frac{1.33}{1.00})=53.06
Why?

Hint: Use Snell's law to find the angle the light makes upon refraction.
 
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