Question $6[12$ marks$]$

A flat plate is kept in an air stream at temperature $20C.$ The velocity of the air is $3\frac{m}{s}.$ The plate measures $5020cm$ and is maintained at a uniform temperature of $100C.$

The properties of air at the mean film temperature, $T_r=\frac{20+100}{2}=60C$ are: $=1\mathrm{.}06k\frac{g}{m^3}$; $v=18\mathrm{.}97{10}^{-6}\frac{m^2}{s}$;$k=2\mathrm{.}894{10}^{-2}\frac{W}{m}.K$;$Pr=0\mathrm{.}696.$ Compare the heat loss from the plate when the air flows a$)$ parallel to $50$ cm side and b$)$ parallel to $20$ cm side.