Exercise Heat transfer Plastic material of thermal conductivity 0.9 KJ/mhk is used to insulate copper wire of radius 10 mm to a thickness of up to 5 mm. The convecture heat transfer coefficient h on the surface of the wire is 50 KJ/m2hk what is the effect of the insulation on the heat transfer rate? What should be the outer radius of the insulation such that the surface temperature is kept at the same value without the insulation