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!

Homework Help: Polarization by reflection and Brewsters Angle

  1. May 4, 2013 #1
    1. The problem statement, all variables and given/known data

    A beam of light is reflected off the surface of some unknown liquid, and the light is examined with a linear sheet polarizer. It is found that when the central axis of the polarizer (that is, perpendicular to the plane of the sheet) is tilted down from the vertical at an angle of 54.3 Degrees,the reflected light is completely passed provided the transmission axis is parallel to the plane of interface. From this information, compute the index of refraction of the liquid.

    2. Relevant equations
    tan θp=nt/ni

    3. The attempt at a solution

    So I think that the since the light is completely passed through the polarizer that my angle θp is just the 54.3 degrees that the polarizer is tilted at, but when I draw up what I believe to be happening I think that brewsters angle which is also the angle of reflection is 35.7 degrees rather than 54.3. But if I was to plug this into the equation above and solve for nt I get a value less than one. Using 54.3 degrees gives me an answer that makes sense. I'm just not sure why I use that angle, any help?
  2. jcsd
  3. May 5, 2013 #2


    User Avatar
    Homework Helper
    Gold Member
    2017 Award

    Why do you think the Brewster angle is 35.7 degrees rather than 54.3 degrees?
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook

Have something to add?
Draft saved Draft deleted