Region $1,$ for which $\backslash$mu $\_(1)=2\mathrm{.}5\backslash$mu $\_(0)$ is defined by z while region $2$ for which h$\backslash$mu $\_(2)=4\backslash$mu $\_(0)$ is

defined by z$>0.$ If B$\_(1)=6$a$\_($x$)-4\mathrm{.}2$a$\_($y$)+1\mathrm{.}8$a$\_($z$)($mWb$)/($m$^(2))$ find H$\_(2)$ and the angle H$\_(2)$ makes

with the interface.