$10.$ A $2$ GHz plane wave in air is incident upon a conducting medium with r $=4$ and $=2$ S$/$m

at an incidence angle of $60.$ If the wave is perpendicularly$-$polarized $($TE$)$ determine:

$($a$)$ the reflectivity and transmissivity, and

$($b$)$ the effective refraction angle.

$3$