# EM waves in matter (electrodynamics)

1. Dec 9, 2009

### maverik

I'm having some trouble understanding this module. It would be great if anyone could help.

In a homogeneous nonconduction region where μr = 1, find εr and ω if

E=30(pi)e[i(ωt-4/3y)] in z direction

H=0.1e[i(ωt-4/3y)] in x direction

I am to understand that for a homognous nonconduction region D=εE and ε=εrε0. However, just equating εr=D/ε0E doesn't seem right. Judging from textbooks and notes I am assuming i must use Maxwell's eqn's for a homogenous nonconducting region, but I'm not sure where to get started. Similarly for ω i can equate ω=(ln|B/10μ0|+4/3y)/t. But again, I'm not sre that this is right.

If anyone could point me in the right direction that'd be great!

2. Dec 10, 2009

### gabbagabbahey

There's nothing wrong with saying $\epsilon_r=\frac{D}{\epsilon_0 E}$...but since $D$ is not given to you, you'll need to express it n terms of the parameters that are given to you in the problem (like $\omega$, $y$ and $t$)...to do that, take a look at what $\mathbf{\nabla}\times\textbf{H}$ is....

As for finding $\omega$, try calculating $\mathbf{\nabla}\times\textbf{E}$ and compare it to the relevant Maxwell equation...