Copper wire with a diameter of 0.5 cm is covered with a 0.65-cm layer of insulating material having a thermal conductivity of 0.242W/m⋅K. The air adjacent to the insulation is at 290 K. If the wire carries a current of 400 A, determinea. the convective heat-transfer coefficient between the insulation surface and the surrounding airb. the temperatures at the insulation-copper interface and at the outside surface of the insulation