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Old Mar 29th 2009, 12:42 PM   #1
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optics problems: Lens' Law

A flashlight on the bottom of a 4.25 m deep swimming pool sends a ray upward and at an angle so that the ray strikes the surface of the water 2.50 m from the point directly above the flashlight. What angle (in air) does the emerging ray make with the water's surface?

and

A submarine is 308 m horizontally out from the shore and 110 m beneath the surface of the water. A laser beam is sent from the sub so that it strikes the surface of the water at a point 228 m from the shore. If the beam just strikes the top of a building standing directly at the water's edge, find the height of the building.

They are really the same problem, I can't plug in a value greater than one for the sin-1 when using Lens' law. I'm not sure how to proceed with either one when I get there. Thank you.
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Old Mar 30th 2009, 02:40 AM   #2
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Use tan to find the angle i and apply Snell's law to find angle r.
1sin r = 1.34sin i
Help you with the first question and you can do the second one
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Last edited by werehk; Mar 30th 2009 at 02:40 AM. Reason: give detail
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