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Old Jan 11th 2012, 09:37 PM   #1
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reflection and refraction

Hi!
So this is a question from reflection and refraction, and I have to find angle deta

Last edited by Koko; Jan 24th 2012 at 01:23 PM.
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Old Jan 12th 2012, 08:38 AM   #2
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If the light goes from one medium to another without bending, then it is entering that latter medium at a right angles.

That said, without knowing the angles of the rectangle formed by the prisms, I don't think there is a single solution...
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Old Jan 12th 2012, 06:59 PM   #3
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If this helps the answers are angle deta 1 = 44 degrees and angle deta 2 = 53 degrees. I'm currently trying to work it out backwords... hey but can you explain me this thing to why when the light's not changing direction it's going to another medium in 90 degrees?
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Old Jan 13th 2012, 07:58 AM   #4
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Isn't that not obvious? The angle of incidence is zero, so will be the angle of refraction.

From a formula standpoint, we know that:

sin i / sin r = n

If i = 0, then sin i = 0.

Whatever be n, , sin r will equal to 0, which means that r will always be 0.

Coming back to the original question, aren't you asked to find delta 1 and delta 4? What is the exact question anyway? Did you do an experiment?
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Old Jan 13th 2012, 09:51 AM   #5
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Okay, so yea I'm suppose to find angle deta 1 and 4 but I do have the answers and that's why I brought them up. Cuz sometimes I work backwards with the answer to find out the process. And it wasn't an experiment and all the info that was given was the drawing plus the fact that light does not bend as it changes medium.
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Old Jan 13th 2012, 10:31 PM   #6
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Well, if the diagram is good, then we get theta 2 = 30 degrees.

This said, we get:

sin i/sin r = 1.4

Giving i = 44.42 degrees, which is 44 to 2 sf.

So, I guess the rectangle is 90 degrees all around...
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Old Jan 14th 2012, 06:46 PM   #7
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I'm just assuming that my teacher forgot to make it clear that it's a rectangle.. cuz it seems like there's no way it would work out unless we know that. So I did get the answer and the process as well. Thank you very much!
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Old Feb 10th 2012, 09:46 AM   #8
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Hi, refractive index can be found in many cases. certainly light passing from lighter to denser medium.i.e.
n = sini/sinr=velocity of light in air or vaccum/ velocity of light in denser medium= 1/sinc(where c is a critical angle= real depth of denser medium/ apparent depth. these are all formula for refractive index, check out which one is applicable to your question. anwaar
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