A 20 mm diameter copper pipe is used to carry heated water, the external surface of the pipe is subjected to a convective heat transfer coefficient of h = 6 W/m²K, find the heat loss by convection per metre length of the pipe when the external surface temperature is 80°C and the surroundings are at 20°C. Assuming black body radiation what is the heat loss by radiation? T₁ = 20°C T₁ = 80ºC L 20 mm diameter