# How to find the amplitudes and polarisation of travelling waves

1. May 31, 2012

### faraaa

1. The problem statement, all variables and given/known data

Plane monochromatic waves are propagating in free space parallel to the x-axis
in both positive and negative directions. At the origin the fi eld strengths are
given by:
Ez = E0 cos wt Ey = 3E0 cos wt
cBz = E0 cos wt cBy = E0 cos wt
Find the amplitudes and polarisations of the forward and backward travelling
waves, and the net energy flux

3. The attempt at a solution

I only get the backward amplitude which is 2E0 parallel to y-axis and the net flux which is E0^2/Z0

Can anyone help to find the forward amplitude?

2. Jun 1, 2012

### dimension10

$$y=A\cos\left(\omega t+\phi\right)$$

Isn't the answer quite easy to derive now?