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some basic doubt on physics

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arava prakash

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1.why the light is having color ?
2.black light is possible or not? as all colored light is possible
 

albbg

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Light is made by photons having different wavelengths. Each wavelenght in the visible spectrum is associated, by our brain to a color. When photons of each visible wavelength are mixed toghether we perceive the light to be white.
When this white ray hit a surface part of the wavelength will be absorbed, while other will be reflected depending from the material of the surface. The mix of the reflected wavelengths will be then perceived as a color. If all the wavelengths are absorbed we will percive black, that is no ligth.
 

one25

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My response is similar with the one of albbg, only a little difference:

If all the wavelengths are absorbed we will percive black, that is no ligth.

If all visible wavelenghts.
 

curiouscase

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Most things as explained by other members. I just want to comment regarding black light, I am not sure what you mean here by black light. Are you referring black as one of color as light?
But, indeed we have black light as ultraviolet light (UV-A ). The name could be misleading sometime.
 

albbg

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I am not sure what you mean here by black light. Are you referring black as one of color as light?
.

Yes you are right in general we could also include infrared and ultraviolet radiation in the term "light". However the term "light" is usually referred to the EM wave falling into the spectrum of frequencies (or better wavelengths) visible by the human eye.
I think, given a part the EM spectrum we can define "black" the absence of EM radiation having frequency inside the part of spectrum we choose.
 

BradtheRad

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Don't know for sure, but I believe our light receptor cells (in our retina) are at the proper size to interact with certain wavelengths (what we call visible light).

Some insects can see ultraviolet (what we call 'black light'). Their eyes are small enough to interact with ultraviolet wavelengths.

I imagine it would require enormous eyes to see infrared light.

There are some snakes which have skin receptors which can pick up infrared radiation from nearby animals.
 

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