A chemical reaction is being carried out at constant pressure in a packed bed between two coaxial cylinders with radii of 1.2 cm and 1.8 cm. The entire inner wall is at a uniform temperature of 500°C and there is almost no heat transfer-from this surface. The reaction releases heat at a uniform rate of 500 kW/m3 through out the reactor. The effective thermal conductivity of the packed bed is 0.55 W/m.K. Determine the temperature of the outer wall.