Consider water is to be heated in a tube equipped with electric resistance heater on its surface. The power rating of the heater and inner surface temperature are to be determined? Properties of tube and water are given below; Tube length L= 7 m, Tube Diameter of Tube D= 2cm, Surface heat flux is constant, water inlet/outlet Temp. Tinlet= 12 C, Toutlet= 70 C For water q= 992.1 kg/m , V=0.008 m /min, k= 0.631 W/mC, y= 0.658 10-m/s, 4179 j/kg C, Pr= 4.32 Cp=