A composite wall is made up of three layers:Layer $1$: k$1=1\mathrm{.}2$ W$/$m$-$K$,$L$1=0\mathrm{.}02$ mLayer $2$: k$2=0\mathrm{.}8$ W$/$m$.$K$,$ L$2=0\mathrm{.}01$ mLayer $3$: k$3=0\mathrm{.}04$ W$/$mK$,$ L$3=0\mathrm{.}03$ m If the wall has a uniform cross$-$sectional area of $2$ m$?,$ calculate the overall thermal resistance and the heat flux if the temperature difference across the wall is $40\backslash$deg C$.$