# Permitivity, and relative permitivity

1. Apr 25, 2007

### neu

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

For a plane em wave in vacuum can write $$k=\frac{w}{c}$$

what is the equivalent relation in a dielectric?

2. Relevant equations

$$\frac{1}{c^2}={\epsilon}{\mu}$$

3. The attempt at a solution

$$k=\sqrt{{\epsilon_{r}}\epsilon\mu}.w$$

This right?

Last edited: Apr 25, 2007
2. Apr 25, 2007

### Meir Achuz

Yes, but you could keep the c instead of epsilon0 and mu0.

3. Apr 25, 2007

### neu

ok so: $$\frac{1}{c}=\sqrt{\epsilon_{0}\mu_{0}}$$

so how is $$\epsilon$$ and $$\mu$$ related to c?

is it $$\frac{n}{c}=\sqrt{\epsilon\mu}$$?

4. Apr 26, 2007

### Meir Achuz

Yes, if you mean $$\epsilon=\epsilon_r\epsilon_0.$$