A radiator is made with 2-mm-thick plain carbon steel. It contains water at 60 deg C with a convection heat transfer coefficient of 120 Wm-2 K-1 The two large faces of the radiator, measuring 1.1 m \times 0.6 m, are exposed to air at 18 deg C with a convection heat transfer coefficient of 35 Wm-2 K-1 (1) Calculate the overall heat transfer rate from the water to the air. [8] (ii) Calculate the temperature of the outer surface of the radiator. [3] (iii) From the materials listed in your tables, suggest an alternative to plain carbon steel, and explain your reasons. With your chosen material, calculate the water temperature required to deliver the same heating rate as the plain carbon steel radiator.