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How does the type of surface affect the amount of heat absorbed or radiated?
Answer 1:

Surfaces which are reflective absorb less heat because the incoming energy is reflected away. It also turns out that the same is true for heat leaving an object - reflective surfaces try to emit heat but it tends to get reflected back inside the object so it gives off less heat. So non-shiny black surfaces, like asphalt for example, will both absorb more heat, and give off more heat. This is why the spectrum of electromagnetic radiation given off by a heated object is called "black body radiation", because a perfectly black body will absorb and emit the most electromagnetic radiation

.

Answer 2:

When you talk about heat, it can be transported in three different ways:
- Conduction: molecules crashing into each other, passing heat from a warm area to a colder area directly through a material
- Convection: molecules carrying the energy through a liquid or gas
- Radiation: heat being transferred by electromagnetic radiation (light)

If two surfaces are in contact with each other, the contact between the two will help determine the ability for heat to transfer through conduction. Rougher surfaces will likely have less contact and transfer heat less effectively. Convection should not be affected much by this. If a surface is particularly rough or smooth, this may affect how much radiative heat it can absorb as well, but this is complicated, and depends on the size scale of the roughness. The type of material (glass, metal, plastic, etc) will also affect each of these.



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