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Light and reflective objects


Gypsy Cake
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Okay, a question has popped into my head and my teacher couldn't answer it. I hope it makes sense.

 

The things I know

A perfectly polished surface is one which is completely smooth. A white suface is one which emits all the light frequencies it absorbs.

 

What I don't get

What's the difference between a polished white surface and a polished silver suface eg. mirror? A mirror reflects any frequency that hits it but only at an angle of reflection whereas a polished white surface would absorb the light and emit in all directions thereby displaying white.

 

My attempt at explaining

Perhaps somehow the mirror doesn't absorb the light and then emit it. Maybe the light bounces off. A white surface absorbs it then photons randomnly come off.

 

 

Your thoughts please.

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Something to think about. Metals (mirrors) when the absorb and emit (which they do do) the angle at which the light is emitted is highly depended on the angle of incidence.

 

Remember light cannot just "bounce" as it travels in straight lines.

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There are differences in what happens to the electric field at the interface (conductor vs insulator) and whether anything happens between the absorption and emission of the light — things that are white sometimes are emitting light that was absorbed as UV, for example.

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Klaynos:

Right okay. So with metals the emission angle of photons is dependant on the angle of incidence but why? what happens when they're absorbed that leads to a single direction of emission?

 

Swansont:

There are differences in what happens to the electric field at the interface (conductor vs insulator) and whether anything happens between the absorption and emission of the light

Sorry, how does the electric field affect emitted light?

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Klaynos:

Right okay. So with metals the emission angle of photons is dependant on the angle of incidence but why? what happens when they're absorbed that leads to a single direction of emission?

 

Swansont:

 

Sorry, how does the electric field affect emitted light?

 

I can't go into this right now, which the people on IRC will understand, but you need to understand how light is reflected... if I get a chance I shall try and explain tomorrow...

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Sorry, how does the electric field affect emitted light?

 

Light is an electromagnetic wave. The restrictions on the electric field at the surface where reflection would take place will affect what happens.

 

I suspect there will also be a difference in how flat some materials can be made, based on their structure, that might disallow specular reflection.

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