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Heat Energy and Surface
Name: Thomas
Status: student
Age: 14
Location: N/A
Country: N/A
Date: 2000-2001
Question:
Which type of surface, dull or shiny, absorbs the most
heat energy?
Replies:
Hello,
I assume that by heat energy you mean radiant energy, the type that
requires no intermediary medium for its transfer, sunlight, for an example,
which is transmitted across vast space vacuum.
In general, the NET absorption by a surface depends on its absorptivity,
transmissivity, reflectivity, and emissivity. At the same time that a
surface absorbs or transmits light, it also emits and reflects incoming
radiation.
A shiny surface (shiny as seen in visible light) is likely to reflect a
larger portion of thermal radiation it receives than a dull surface. In
that sense, the net thermal radiation absorption by a dull surface is
higher than a shiny surface of the same material and geometry.
As a qualifying statement, I should add that there are variety and degrees
to dullness and shininess, and it may be possible (due to a variety of
special circumstances) to have a material with a shiny surface that absorbs
more than a slightly less shiny one , but this is more of an exception than
a rule.
AK
Ali Khounsary, Ph.D.
Advanced Photon Source
Argonne National Laboratory
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