A very long cupper fin (k=200 W/m.K) with a cross sectional area of Ac = 5 mm2 and

perimeter of P = 8 mm, is attached to a surface whose temperature is Tb. The fin is subjected to

convection heat transfer with h=35 W/m2. C and T = 25 C.

(a) If fin temperature is 50C at a distance of 20 cm from the surface, what is the surface temperature, Tb ?

(b) Consider the case of 10 fins installed on a surface while the surface has a constant temperature of Tb and an area of 100 mm2, find fin effectiveness for this surface