3 votes
Accepted

What exactly is "dense" in Optical Density?

In this particular context, "optical density" refers to the index of refraction of the material. This is not a common usage for physicists, as can be seen from the comments below. So, beware ...
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3 votes

Are laser diffuse reflections really so dangerous?

imagine...I shine it on a white wall. How small is the spot? With a lens to focus it, you can focus all of that energy onto an incredibly tiny spot. Let's now say that I am at 1m distance from the ...
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  • 9,307
2 votes

Are laser diffuse reflections really so dangerous?

Your calculation is fine, but it makes some assumptions that would be an unwise foundation on which to rest your eye safety. You assume that you are 1 meter away. This might be true most of the time, ...
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1 vote

How are the matrices for the RGB to/from CIE XYZ conversions generated?

The previous answer is completely correct, but I interpret the question a little differently - rather than how to calculate the matrix, which of the matrices is correct? Short answer: Wikipedia is ...
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1 vote

Tangential rainbows?

It is kind of hard to tell what is what from the photos - I'm sure it was stunning in person though. I reckon what you're seeing is a form of halo though - an optical phenomenon produced as light ...
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  • 11
1 vote

How do you make light?

How about an AC electric circuit attached to an antenna - like any radio, cellular, or TV transmission tower. Granted it takes a bit of work :-) to make an oscillator in the visible-spectrum ...
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1 vote
Accepted

How do you make light?

Quanta of em radiation called photons are produced in many reactions involving fundamental particles, atomic nuclei or whole atoms. These include thermal vibration of atoms and molecules; transition ...
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