1. The problem statement, all variables and given/known data Two harmonic transverse waves of the same frequency with displacements at right angles to each other can be represented by the equations: y = yo*sin(wt-kx) z = zo*sin(wt-kx + phi) where yo and zo are nonzero constants The equations represent a plane polarized wave if phi equals (a) sqrt(2) (b) 3pi/2 (c) pi/2 (d) pi/4 (e) 0 2. Relevant equations 3. The attempt at a solution I'm kind of lost. If the two displacements are at a 90 degrees to each other then the phi term will only push one sine out of phase with the other one, but the two waves will still have displacements that are 90 degrees apart. So i have no idea how you can ever get a plane polarized wave since the wave would have to be sitting in one plane and these waves are not. The answers are given so I know the correct one, but I want to understand how to solve. Thanks a lot.