Question

An electromagnetic wave of frequency $5\text{GHz}$ is travelling in a medium whose relative electric permittivity and relative magnetic permeability both are $2$. Its velocity in this medium is _______ × ${10}^7\text{m/s}$.

Answer 1

Given:
$f=5\text{GHz}$
${ϵ}_r=2$
${\mu }_r=2$

We know that,
$v=\frac{c}{n}[n\to \text{refractive index}]$

$\Rightarrow v=\frac{c}{\sqrt{{ϵ}_r{\mu }_r}}$

$\Rightarrow v=\frac{3\times {10}^8}{\sqrt{2\times 2}}=15\times {10}^7\text{m/s}$