A white coating is applied to the Copper sheet in order to increase the absorbance of the sunlight?
Answers
No requirement of coating appear on sheet of copper as copper is very less reactive in comparison to other metals such as iron or nickel. Thus copper will not get oxidises in present of air and it remain in unoxidised form whereas, iron get oxidises to Fe+2 and it forms rust and therefore a coating of zinc is required for the prevention of oxidation of iron sheet.
Hence, covering the surface of copper sheet with any other coating may result in decrease in IR transparency with thickness coming from sunlight. The thickness more than 0.0125 milimeter may result in decrease in IR transparency and make it more emmisive and thus decreases the absorbance and thus can not be used for space crafts or for purpose related to it. In presence of coating on copper, it not be able to absorb no or very low sun light which can be used to produce solar energy at time of space travelling.
Thus, a white coating or no coating is required for the absorbance of sunlight.