A certain fluid (with properties listed below) is heated from 25 to 75 °C as it moves at 0.2 m/s through a straight thin-walled tube of 12.7-mm diameter. The tube is 10 m long and provides a uniform heat flux. The fluid enters the tube with a fully developed velocity profile and a uniform temperature profile.

a) What is the required heat flux?
b) What is the thermal entrance length?
c) What is the surface temperature of the tube at the exit (x-3 m)?
d) What is the surface temperature of the tube at a distance of 0.5 m from the entrance?