A steel tank of wall thickness 8 mm contains water at 80°C. Calculate the rate of heat loss per m2 of tank surface area when the atmospheric temperature is 20°C. The thermal conductivity of mild steel is 50 W/m K, and the heat transfer coefficients for the inside and outside of the tank are 2,500 and 20 W/m2K, respectively. Calculate also the temperature of the outside surface of the tank.