$(6)$ Consider a $5-$m$-$high, $8-$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 $\frac{W}{m}*K,$

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 $100C,$ 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.