Consider a tube $($diameter $=2$ cm$,$ length $=13$ m$)$ of which a uniform heat flux is applied

from all surfaces. The volumetric flow rate of water flowing in the tube is $5$ L$/$min$.$ Inlet and

outlet temperatures of water are $10$C and $80$C$,$ respectively. Determine the $($a$)$ rate of

convection heat transfer, $($b$)$ inner surface temperature of the pipe at the exit.