Consider a $4-$m$-$high, $10-$m$-$long, and $0\mathrm{.}22-$m$-$thick wall whose representative

cross section is as given in the figure. The thermal conductivities of various

materials used, in $\frac{W}{m}*C,$ are $k_A=k_F=2,k_B=8,k_C=20,k_D=15,$ and $k_E=35.$ The left

and right surfaces of the wall are maintained at uniform temperatures of $300C$ and

$120C,$ respectively. Assuming heat transfer through the wall to be one$-$dimensional,

determine $($a$)$ the rate of heat transfer through the wall; $($b$)$ the temperature at the point

where the sections $B,D,$ and $E$ meet; and $($c$)$ the temperature drop across the section $F.$

Disregard any contact resistances at the interfaces.