1. Limited time only! Sign up for a free 30min personal tutor trial with Chegg Tutors
    Dismiss Notice
Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Find the formula for refraction angle?

  1. Jun 14, 2017 #1
    1. The problem statement, all variables and given/known data
    Screenshot_30_2014_Phy.png

    2. Relevant equations
    Snell's Law
    sin tetha1/v1 = sin tetha2/v2
    n1 = c/v1
    n1 . sin tetha 1 = n2 . sin tetha 2

    3. The attempt at a solution
    I try to make triangle out of line PO, so that it will have correlation to tetha, since o = center, then let's say there's point C at circle circumference. then POC is isosceles triangle.
    PC^2 = PO^2 + CO^2 - 2PO.CO.cos tetha
    PC^2 = 2R^2 - 2R^2 cos tetha
    PC^2 = 2R^2 ( 1 - cos tetha)
    n value for air = 1.00 ? but I cannot find the correlation tetha to n, and especially h...?
     
  2. jcsd
  3. Jun 14, 2017 #2

    Doc Al

    User Avatar

    Staff: Mentor

    Extend the line OP. That gives you the normal to the surface. The angle of incidence can be related to h & r with a bit of trig.
     
  4. Jun 14, 2017 #3
    i tried to extend OP but still don't find the correlation with r and h
     
  5. Jun 15, 2017 #4
    Give me more clue please?
     
  6. Jun 15, 2017 #5

    haruspex

    User Avatar
    Science Advisor
    Homework Helper
    Gold Member
    2016 Award

    Adding some more labels...
    Q is the point where the vertical marked h meets the horizontal through O.
    S is thepoint at the top of the line marked h.
    R is a point beyond P on the line through OP.
    Can you relate angle POQ to h and r?
    Can you relate angle POQ to angle RPS?
    Can you relate angle RPS to φ?
     
  7. Jun 15, 2017 #6
    I tried before, is it right?
    i'm not sure about the normal line I set, and theory I used
    1-5_2014_phys.png
     
  8. Jun 15, 2017 #7

    Doc Al

    User Avatar

    Staff: Mentor

    Now you're cooking. Looks perfect!
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Have something to add?
Draft saved Draft deleted