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Name: Michael N.
Status: other
Age: 40s
Location: N/A
Country: N/A
Date: 7/17/2003
Question:
Why do certain metallic objects become hot when they are exposed to sunlight? I thought rough black surfaces are best absorbers of light whereas metals are smooth and reflective.

Replies:
Michael,

When light strikes an object, three things can happen -- light is absorbed, reflected, or transmitted. Because there are no such things as perfect reflectors or transmitters, anything will warm up if exposed to sunlight because at least some light will be absorbed. You are correct in your belief that flat black objects will warm up the most. That is because most all of the wavelengths of sunlight are absorbed best by a surface color (black) that reflects the least. Shiny objects are not as good as sunlight absorbers because so much of the incident light is reflected. It's the absorption of solar flux that warms things up.

Regards,
ProfHoff 697


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