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Question on refraction

  1. Aug 9, 2011 #1
    In the diagram, there are two light rays that start from the same plane and fall on another plane which is parallel to the first one. The light ray P goes through a medium of higher refractive index than vacuum/air and refracts. So, which one of them will reach the second plane first? Ray P will travel a shorter distance compared to Q but will be slower than Q.

    Attached Files:

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  2. jcsd
  3. Aug 9, 2011 #2


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    Apply Snell's law to find the path length. Then find the transit time. Just go through the exercise.
    You could start with A=0.....
  4. Aug 10, 2011 #3
    I used the refractive medium as a glass slab, and used 30 deg as angle A(see the attachment).

    Conclusion: P is slower than Q at 30 deg.

    I think P will always be slower than Q.

    Attached Files:

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