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