D$9\mathrm{.}5.$ The unit vector $0\mathrm{.}64$ax $+0\mathrm{.}6$ay $0\mathrm{.}48$az is directed from region $2($r $=$

$2,$ r $=3,$ $2=0)$ toward region $1($r$1=4,$ r$1=2,$ $1=0).$ If B$1=($ax $2$ay $+$

$3$az$)$ sin $300$t T at point P in region $1$ adjacent to the boundary, find the ampli$-$

tude at P of: $($a$)$ BN$1$; $($b$)$ Bt$1$; $($c$)$ BN$2$; $($d $)$ B$2.$