from heat transfer A long stainless steel rod of 30-mm diameter (k = 14.9 W/m.°C, p =7900 kg/m³, Cp= 477 J/kg.°C, and a = 3.95 10-6 m²/s) has a surface temperature of 653K when the time is 30min. Determine the amount of heat transfer per unit length of the rod when surrounding medium temperature is 25°C with an average convection heat transfer coefficient of h = 60 W/m².°C using 

a). Heisler charts 

b). One term approximation method