Three thin-walled, long, circular cylinders 1, 2 and 3 of diameters 150mm, 250mm and 350 mm respectively are arranged concentrically. Temperature of cylinder 1 is 80 K and that of cylinder 3 is 300 K. Emissivity of cylinder 1, 2 and 3 is 0.05, 0.1 and 0.2 respectively. Assuming that there is vacuum inside the annular spaces; determine the steady state temperature attained by cylinder 2.