) In a plane composite wall system, wall A has a thermal conductivity k_{A} = 15 W / m .K, thickness L_{A} = 5mm , and wall B has a uniform volumetric energy generation dot q_{R} = 2 * 10 ^ 5 * W / (m ^ 3) k b = 25W / m .K L_{a} = 30 mm. The left surface of wall A is well- insulated and the right surface of wall B is exposed to convection with T_{0} = 15 deg * C h = 10W / (m ^ 2) .K . There are straight rectangular fins on the right surface of wall B with length L_{f} = 20mm , thickness t = 2mm spacing between each fin 8 = 2mm and thermal conductivity k f = 250W / m .k .

Obtain the temperature T3 explaining all the calculations made in the fin area