Question

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

Answer 1

Given $:f=5GHz$
$\epsilon _{r}=2$
$\mu _{r}=2$
velocity of wave $\Rightarrow v=\frac{c}{n}$ ....... (1)
where, $n=\sqrt{\mu _{r} \epsilon _{r}}$ and $c=$ speed of light $=3\times 10^{8}m/s$
$n=\sqrt{2 \times 2}=2$
put the value of $n$ in we get
$\Rightarrow v=\frac{3 \times 10^{8}}{2}=15\times 10^{7}m/s$
$\Rightarrow X\times 10^{7}=15\times 10^{7}$
$X=15$