A plane wave in free space $($z $0)$ is incident normally on a large block of material with $($s$,=12,$ M$,=3,0=0)$ that occupies z $0.$ If the incident electric field isE $-30$ cos $($ct $-$ z$)$a$,$ V$/$mFind $($a$)$ w$,($b$)$ the standing wave ratio, $($c$)$ the reflected magnetic field, $($d$)$ the average power density of the transmitted wave.