how Visible Light frequencies add up

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neptune

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Hi,
if i have two visible light waves (monochromatic) of different freq. and i mix them up then how would i calculate resultant frequency ?
 
Unless the mixing is done in a non-linear medium the mix will remain just that...a mix with the frequencies unchanged.
 
Visible light must follow some mathematical formula to add two colours to make other colours.
like R+G = Y , red = 430–480 THz, green = 540–610 THz to yellow = 510–540 THz
 
I think you are mixing two different principles here. One is heterodyning as mentioned above and refers generating sum and difference frequencies.

The other (post#5) is our perception of color based on the differential excitation of the cones in our eyes. Check: https://en.wikipedia.org/wiki/Color_perception . It might also be worth searching on "color blindness."

John
 
Let me make it clear - if i have 2 light waves 1st light -200THz and 2nd light-300THz .. now we mix them up what would be the resultant frequency
 
It all depends. How do you propose to 'mix them up'? Is a non-linear medium involved? If so, what is it?
 
Let me make it clear - if i have 2 light waves 1st light -200THz and 2nd light-300THz .. now we mix them up what would be the resultant frequency


Hi,

If you shine two different color lights onto a white surface you get the 'mix' but the mix is just what the eye interprets when it sees two frequencies instead of one. They dont actually change frequency, you just get two frequencies instead of one.
 
I am mixing two lasers in Vaccum
In that case there is no medium involved so IMO there won't be any sum or difference frequency generation.
 
so if i mix up Red and green Laser in vaccum then i wont get yellow light ?

So how are you 'mixing' them?.

I would suggest. like others have, you're just pointing them together - which will give you a red light and a green light.
 
I think MrAl put it best already.

To re-state what I think he said:

The two frequencies will not mix in a vacuum.

It is only your brain that will interpret the reception of red and green to produce yellow in your head.

Outside of your head the two frequencies will remain independent and no mixing will occur.

Not sure if this helps
 
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As Nigel said the light won't 'mix' at least not on a fundamental level, if you converge a red and green laser on a point you will see yellow light, but the fundamental frequency of the light won't change, if you look at it on a spectrograph you'll still see red and green only. Human visual perception is a lot more complicated than people take for granted.
 
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