$2)$ Consider two smooth circular tubes attached one another as seen in the figure below. The diameter of the tubes is $20$ mm and the lengths are expressed in the figure. Constant and uniform heat flux of $\backslash (100\backslash$mathrm$\{$~W$\}/\backslash$mathrm$\{$m$\}^\{2\}\backslash )$ applied on the first pipe. The second pipe wall temperature maintained at constant temperature of $350$ Kelvin $.$ Air as hydrodynamically and thermally developed flow at $\backslash (10^\{\backslash$circ$\}\backslash$mathrm$\{$C$\}\backslash )$ enters the first tube at the cross$-$sectional point of one $(1)$ with a mean and constant velocity of $\backslash (0\mathrm{.}8\backslash$mathrm$\{$~m$\}/\backslash$mathrm$\{$s$\}\backslash ).$ Calculate the average bulk temperature at point $2($outlet of the first tube$)$ and $3($outlet of the second tube$).$