PRACTICE EXERCISE $5\mathrm{.}9$ A homogeneous dielectric $1$er $52\mathrm{.}52$ fills region $11$x $,02$ while region $21$x $.02$ is free space. $($a$)$ If D$1512$ax $210$ay $14$az nC$/$m$2,$ find D$2$ and $2.($b$)$ If E$2512$ V$/$m and u$2560,$ find E$1$ and $1.$ Take $1$ and $2$ as defined in Example $5\mathrm{.}9.$ Answer: $($a$)12$ax $24$ay $11\mathrm{.}6$az nC$/$m$2,19\mathrm{.}75,($b$)10\mathrm{.}67$ V$/$m$,77.$