WEBVTT
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were us to consider the situation in which ah,
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light Ray is incident. Yeah, on Polly staring
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from surrounding air. And then we're gonna do it
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when it's surrounded by water. And then when also
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, that Polly staring. It's surrounded by carbon die
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sulfide. So I wrote the index of refraction for
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ERAS and survey Polly staring as in soapy water,
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is in sub w and carbon, uh, die
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sulfide as in subsea. Okay, so we want
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to find that critical angle for all of these and
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using Snell's law. The critical angle happens when the
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angle of refraction is 90 degrees. So sign of
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90 is one. So we can easily drive the
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critical angle from that so sign of fate A.
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C. Then the critical angle would be equal to
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incident to reverence of one. But for part,
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a were asked to consider air. So in sub
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two is the index of refraction of air Annan.
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Someone is the index of refraction of Polly steering and
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okay, so now solving for data see where the
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index are the critical angle, we find that it's
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equal to the inverse sine of that ratio. Insa
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bait and stumpy, so plugging those values in for
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those index of re fractions. We find that this
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angle is approximately 90 degrees for part B were asked
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to do the exact same thing. Except for this
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time we're gonna surrounded by water instead of air.
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So solving for that critical angle, same formula,
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we find that it's equal to the inverse sine of
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this time the ratio of the index of refraction of
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water police. Terry. We find that this is
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approximately 30 degrees, which can be boxing is their
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solution to be. And then for Parsi asked us
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to do it for carbon die sulfide. But if
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you go back to this first page here, we
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see that carbon die sulfide has a greater index of
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refraction than Polly staring. So we can conclude then
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that since ah, in subsea is greater than and
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, said P, it's not possible for there to
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be told any total internal refraction. You can't take
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the sign of something there, the inverse sine of
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something that's larger than one. So, um,
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not possible for internal reflection, Lincoln box it in
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as their solution for part C.