Liquid metal heat transfer inside a tube

A liquid metal flows at a rate of 4.0 kg/s through a tube having.

An inside diameter of 0.05 m the liquid enters at 500K and heated to 505K in the tube , the tube eall is maintained at a tempreture of 30K above the fliud bulk tempreture and constant heat flux (q/A= constant) is also maintained . calculate the required tube length (L) the average physical properties of the liquid metal are as follows

m = 7.1*10^-4 Pa.s ; density = 7400 kg/m^3

Cp=120 J/kg .k ; K = 13 w/ m.k