A cylindrical metal rod with emissivity 0.60 has radius 2.0cm and length 20cm. Its flat ends are closed. The rod is initially at a uniform temperature of 700K and is placed in a very large, perfectly black surrounding kept at 0K (so that re-absorption from surroundings may be neglected). Take σ=5.67×10−8Wm−2K−4.
a. (i) Compute the total surface area of the rod that is effective in emitting radiation.
b. (ii) Calculate the amount of thermal energy it radiates in 5min.