
#1
Jul2208, 11:49 PM

P: 27

1. The problem statement, all variables and given/known data
Calculate the angle of refraction for a substance that has a critical angle of 50.5 degrees when that substance is in the air. 2. Relevant equations Apparently the equation I need is: ni *• sine() = nr • sine () My problem is, I have no idea how to use this formula or if it's even the right one  my teacher told me to write it down with no explanation. Please help me, I just need to know what the equation actually tells me  where I am supposed to input data? 3. The attempt at a solution 



#2
Jul2308, 08:36 AM

Sci Advisor
HW Helper
P: 8,961

I think you first need to understand refraction ( see http://en.wikipedia.org/wiki/Refraction) This explains where that equation, whihc you have slighlty wrong, comes from.
Do you have part of the question missing, it doesn't seem to make sense? 



#3
Jul2308, 01:21 PM

P: 27

Alright, I got the correct equation now....it makes a bit more sense with that.
No, that's the question exactly as it was written. My teacher told me to use the index of refraction for air (so, 1.00), the angle of incidence/critical angle (50.5). SInce the refracted angle in 90 degrees from the normal, I was told to use 90. So if I manipulate the equation (where @ = unknown angle)  ni (sin@i) = nr (sin@r) into sin@i = nr (sin@r) / ni so sin50.5 = (1.00)(sin90) / ni equals sin50.5 = 1/ ni or ni = 1sin50.5 which gives me an answer of 1.295967, or 1.3 Am I doing this right? Or I am completely on the wrong track? 



#4
Jul2308, 01:23 PM

P: 27

Angle of Refraction
Typo correction on the last line of the equation:
ni = 1sin50.5 SHOULD READ ni = 1 / sin 50.5 



#5
Jul2308, 02:50 PM

Sci Advisor
HW Helper
P: 8,961

That looks right (asuming the arithmatic is correct)
Your original equation didn't have any angles in it  thats what I meant by it being wrong. 


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