An electrical wire having a diameter of 1.5 mm and covered with a plastic insulation (thickness = 2.5 mm) is exposed to air at 300 K, and h0 = 20 W/m2 K. The insulation has a k of 0.4 W/m K. It is assumed that the wire surface temperature is constant at 400 K and is not affected by the insulation. Find the heat loss per unit length of the wire with the insulation present.