Consider the base plate of a 1200-W household iron that has a thickness of
L 0.5 cm, base area of A 300 cm2, and thermal conductivity of k
15 W/m · °C. The inner surface of the base plate is subjected to uniform heat
flux generated by the resistance heaters inside, and the outer surface loses
heat to the surroundings at T
20°C by convection, as shown in Figure 2–46.