Problem $2.(20$ pts$)$ A current sheet exists between two magnetic materials. The surface current density of the current sheet is vec$(J{)}_s=8$vec$(e{)}_x\frac{A}{m},$ and the surface is the xz plane $($i$.$e$.,y=0).$ The relative permeabilities of magnetic materials are ${}_{r1}=2$ for $y>0($material $1)$ and ${}_{r2}=5$ for $y<mn>0</mn><mtext></mtext><mi>(</mi>$material $2).$ In material