# Permitivity, and relative permitivity

## Homework Statement

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

what is the equivalent relation in a dielectric?

## Homework Equations

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

## The Attempt at a Solution

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

This right?

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Meir Achuz
Homework Helper
Gold Member
Yes, but you could keep the c instead of epsilon0 and mu0.

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

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

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

Meir Achuz
ok so: $$\frac{1}{c}=\sqrt{\epsilon_{0}\mu_{0}}$$
so how is $$\epsilon$$ and $$\mu$$ related to c?
is it $$\frac{n}{c}=\sqrt{\epsilon\mu}$$?
Yes, if you mean $$\epsilon=\epsilon_r\epsilon_0.$$