Centerline Temperature of a Resistance Heater
A 2-kW resistance heater wire whose thermal conductivity is k = 15 W / m \cdot{ }^{\circ} C , has a diameter of D = 4 mm and a length of L = 0.5 m, and is used to boil water (Fig). If the outer surface temperature of the resistance wire is T_{s} = 105^{\circ} C , determine the temperature at the center of the wire.