Posted by Katie on Sunday, May 31, 2009 at 4:01pm.
I don't understand snell's law ( nsin(0)=nsin(0) ) and how to use it with refraction.
also how do i apply that to this problem:
'a light ray enters a square piece of plastci (n=1.39) near a corner. as it encounters the adjacent side it gets refracted along the surface (it hits at the critical angle). what was the original angle with which the ray hit the plastic from air?'
i know the answer (75 degrees) but i don't know how to get there.
please help!

Physics  bobpursley, Sunday, May 31, 2009 at 4:15pm
What does "near a corner" mean? Does that mean the ray is internally reflected once?

Physics  Katie, Sunday, May 31, 2009 at 4:24pm
i have no idea, i just wrote what the question said. but yes that's what i interpreted it to mean

Physics  bobpursley, Sunday, May 31, 2009 at 4:40pm
Then start at the end of the ray.
1.39*sinThetainside=1*sin90
theta inside =46 deg.
Now take that angle back to where it was reflected, so it incident angle at the reflection was 46, then trace back to the corner side, so it leaves the surface refracted at 54 deg, no use Snell's law to find the ray angle outside ..
1.39sin54=1*sinTheta
and I think you will get your 75deg. Draw the figure to make certain you understand it.
Answer This Question
Related Questions
 Physics  The maximum depth of Lake Baikal, in Russia, is 1637 m, making it the ...
 Physics  A ray of light of frequency 5.09 x 10^14 Hz passes from air into flint...
 Physics  n=1.331 for red light in water and n=1.34 for blue light in water. If ...
 Physics Word Problem  using Snell's Law (sin(theta1)/sin(theta2) = v1/v2 where...
 Physics Word Problem  using Snell's Law (sin(theta1)/sin(theta2) = v1/v2 where...
 physics  1.A beam of light passes through the air and enters a diamond at an ...
 Physics  A vat in England nicknamed "Strongbow" is 19.7 m tall, but how wide is...
 Physics  A vat in England nicknamed "Strongbow" is 19.7 m tall, but how wide is...
 college physics  I know you need to use geometry but i don't know how a room ...
 math  Snell's law of refraction can be written as sin i = n sin r, where n is ...
More Related Questions