Calculating Refraction Time in Water: Physics Homework Help

AI Thread Summary
To calculate the time it takes for light to travel through 2.3 km of water with an index of refraction of 1.32, the angle of refraction must first be determined using Snell's Law. The calculated angle in water is approximately 45.01 degrees. The formula for time, considering the effective distance and speed of light in water, is used to find the time taken. The correct calculation yields a time of 15.34 microseconds, indicating a discrepancy in the initial attempt. The discussion highlights the importance of correctly applying refraction principles and formulas in physics problems.
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Homework Statement


Light is originally traveling through air and then enters water with an index of refraction of 1.32. Angle in air at interface is 69 degrees with respect to normal. If thickness of water is 2.3 km, how long does it take in microseconds (1 x 10-6 s) to cross water? Hint: light does not travel straight across water because it is refracted by water. Answer is 15.34.

Homework Equations


nasin\phia=nbsin\phib
n=c/v

The Attempt at a Solution


(1)sin69=1.32sin\phib
\phib=sin-1(sin69/1.32)=45.01
cos\phib=d/h
h=d/cos\phib
nv=c
v=h/t=c/n
t=hn/c=dn/ccos\phib x 106=(2.3 x 103m*1.32)/(3 x 108cos45.01) x 106=14.31
I am not certain what I am doing wrong, but that answer is incorrect.
 
Last edited:
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It looks correct.

ehild
 

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