Optics question- please reply

  • Thread starter ERB225
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Optics question-- please reply ASAP

A person stands against a thick plate of glass, n=1.5. everything on the other side of the glass plate is inside of a circle of radius = 1 meter.
wavelength air = 600 x 10 ^ -9 meters
wavelength of glass = 4 x 10 ^ -7 meters
Critical angle of glass plate = 41.8º

HOW THICK IS THE GLASS PLATE?
 
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Answers and Replies

  • #2
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This problem is pooly formulated and posted.

Glass doesn't have a wavelength, and how far is the person from the glass?

If my eyeball doesn't touch the glass then I will see all the way to infinity, not
just to a 1 meter radius. My eyeball would have to be in fluid contact with the
window in order for there to be a point of total internal reflection which is visible
to me.

That having been said, the glass plate would be 381 Inches thick.
 
  • #3
Doc Al
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I agree that the problem is not clearly stated. I interpret it this way: looking at the person's image from the other side of the glass, every point is only visible inside a circle of radius 1 meter. With this interpretation, the problem is solvable. (The wavelengths are irrelevant.)
 

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