Reflection of Heat Ray by Metal Surface

Abstract

Reflection of heat ray by several metal surfaces is investigated, using, as a heat-ray sourcs, the total radiation of nichrome heat-element of common use, and a thermopile as a detector.
Brass, copper and aluminium are the practical materials for reflector of electric heater. The reflecting power of these materials is in the range of 75-90% for polished surfaces and about 60% for tarnished surfaces Chromium platod copper plate is also tested. Its reflecting power is the same order of that of the above materials. But, owing to its stronger resistance against rust, chromium plating will be widely applied to reflector in near future.
Reflection from rough surfaces-polished surfaces by sand-paper and frosted glass-is investigated, and Wood's theory about reflection of unpolished surfaces is examined and ascertained by our test results, that reflection from rough surface increases as angle of incidence increases.
Reflecting power is well qualified for the measure of polishing, for it quantitatively indicates the degree of finishing of polished surfaces.