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!

Critical angle = brewster angle?

  1. Jun 3, 2009 #1
    1. The problem statement, all variables and given/known data
    when the critical angle=brewster angle, what is the refractive index, if incident n is air=1.


    how is this? i tried differentiating both side and solving but i just get into a big mess, can anyone help me if i am missing something?
    Last edited: Jun 3, 2009
  2. jcsd
  3. Jun 4, 2009 #2
    ive tried pythagoras, and trig idendenties, but all i come up with is x=x??
  4. Jun 4, 2009 #3


    User Avatar
    Homework Helper

    If you want to use identities you can take the sin on both sides and then use [itex]\cos^2x+\sin^2x=1,\;1+\tan^2x=\sec^2x[/itex] to simplify the right hand side.
  5. Jun 4, 2009 #4
    ok thanks i think i got it now... just confused about the algebra
  6. Jun 4, 2009 #5
    all solved, thanks very much
  7. Feb 27, 2011 #6
    I'm still at a loss as to how n = 1.272.

    so getting to:
    1/n = sin(arctan(n))

    then squaring and adding cos^2 gets:

    1/n^2 - cos^2(arctan(n)) = 1

    but any way I rearrange the above formula to get 1/cos^2 for sec^2 ends up resulting in n=1?
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Similar Threads - Critical angle brewster Date
Not a homwork problem, Fresnel Equations Oct 30, 2016
Triangular lattice and criticality Apr 14, 2016
Mean field solution for potts model Jun 25, 2015
Critical energy Mar 13, 2015
Cosmic Inventory Dec 4, 2014