$\backslash$mu $=\backslash$mu $\_(0)()/($bar$)($B$)($x$,$t$)=$hat$($z$)0\mathrm{.}5$sin$[2\backslash$pi $(10^(8)$t$-0\mathrm{.}5$x$-0\mathrm{.}125)]\backslash$mu T

$($a$)$ Find the frequency, wavelength, and the phase velocity. $($b$)$ Find the relative permittivity,

$\backslash$epsi lon$\_($r$),$ and the intrinsic impedance, $\backslash$eta $,$ of the medium. $($c$)$ Find the corresponding $()/($bar$)($E$).($d$)$ Find

the time$-$average power density carried by this wave.