An air heater may be fabricated by coiling Nichrome wire and passing air in cross flow over the wire. Consider a heater fabricated from wire of diameter D = 1 mm, electrical resistivity Pe = 10-6 m, thermal conductivity k = 25 W/mK, and emissivity & = 0.20. The heater is designed to deliver air at a temperature of T = 50C under flow conditions that provide a convection coefficient of h = 250 W/m K for the wire. The temperature of the housing that encloses the wire and through which the air flows is Tsur maximum allowable temperature of the wire is Tmax = 1200C, what is the maximum allowable electric current /? If the maximum available voltage is AE = 110 V, what is the corresponding length L of wire that may be used in the heater and the power rating of the heater? = 1131