A circumferential fin of rectangular profile having a thickness of 1.0mmand a length of 2.0 cm is

Question:

A circumferential fin of rectangular profile having a thickness of 1.0mmand a length of 2.0 cm is placed on a 2.0-cm-diameter tube. The tube temperature is 150ºC, the environment temperature is 20ºC, and h = 150 W/m2 ∙ ºC. The fin is aluminum. Calculate the heat lost by the fin.