Water enters a tube of diameter, D = 60 mm with mass flow rate of 0.01 kg s^-1 as shown in the figure below. The inlet mean temperature is T_m,i=293 K and the uniform heat flux at the surface of the tube is 2000 W m^-2. For the exit mean temperature of T_m,o=353 K, the length of the tube, L is ______ m (rounded off to 1 decimal place).
Use the specific heat of water as 4181 Jkg^-1 K^-1.