# Do two light waves with difference frequencies connect when they meet?

• danielhaish
In summary, this sentence is worrying me because it suggests that the brain can interpret the combination of yellow and blue light as green light, even though there is no filter that would actually do that.
danielhaish
for example the blue light wave have frequency of about 450Thz and the yellow wave have frequency of about 508thz (I found this data in the internet) , so if this two wave would get closer to each other we would observe them as green wave which have frequency of 526Thz .
so my question is weather it just an illusion or does the frequency of the light is really changes , for example what would happens if we will try to point the light to a green filter does it block it or not

Light waves don't combine in that sense, no. If you shine two lights of different colours onto one spot, instruments will still be able to recognise that there are two different frequencies of light. The "mixing" of two colours two make a third is how your eye-brain system interprets a given stimulus. For example, just look at your screen with a magnifying glass and you'll be able to see that whatever colour it appears to be, it's doing it with an array of red, green and blue dots that are close enough to blur together.

PeroK, berkeman and danielhaish
so basically no way that green color blocker would block green light if it source is blue light and green light?

danielhaish said:
so basically no way that green color blocker would block green light if it source is blue light and green light?
Filters block specific frequencies. If you have light that is a mix of two frequencies, one of which is absorbed by the filter and the other of which is transmitted then you will get one of the frequencies transmitted and one absorbed.

What happens in your example depends on what you mean by "blue light", "green light" and a "green color blocker". If your light is a mix of two monochromatic sources, say 400nm (typical blue) and 550nm (typical green), and your filter absorbs wavelengths between 500 and 600nm and nothing else then the green component will be absorbed and the blue component passed. But a "green color blocker" might absorb some frequencies you'd call blue - so you need to specify exactly what light and what filter you have if you want an unequivocal answer.

danielhaish
Ibix said:
Filters block specific frequencies. If you have light that is a mix of two frequencies, one of which is absorbed by the filter and the other of which is transmitted then you will get one of the frequencies transmitted and one absorbed.

What happens in your example depends on what you mean by "blue light", "green light" and a "green color blocker". If your light is a mix of two monochromatic sources, say 400nm (typical blue) and 550nm (typical green), and your filter absorbs wavelengths between 500 and 600nm and nothing else then the green component will be absorbed and the blue component passed. But a "green color blocker" might absorb some frequencies you'd call blue - so you need to specify exactly what light and what filter you have if you want an unequivocal answer.
thanks so I guess there isn't any filter that blocks the yellow light and the blue light but doesn't block them when they combine together

danielhaish said:
so if this two wave would get closer to each other we would observe them as green wave which have frequency of 526Thz .
This sentence is worrying me. That could mean that you are using the" Yellow and Blue 'make' Green" thing that we start our colour experiences with . This is true when you mix paints or pigments and it works by Subtractive Mixing with primary coloured pigments. You are proposing Additive Mixing of coloured spectral monochromatic light But with coloured light or with pigments, the colours we see are a total psychological effect in human colour vision. Electromagnetic waves of any frequencies do not affect each other.
To get a clue about colour vision you need to read about it. This wiki article has a lot of what you need to know.
The fairly well accepted model for human colour vision says that we have just three sets of colour sensors. One that is sensitive to a broad range of spectral reddish colours, one that is sensitive to the greenish range and one that is sensitive to blues. Thinking of the sensors as having colour filters, those filters are actually very broad and actually overlap a lot (see the wiki link). When we look at any colour (including a monochromatic source) all three sensors may get a signal and we assess the colour on the basis of the ratios of the three signals.
Spectral Yellow will stimulate your red and green sensors mainly and Spectral Blue will stimulate (almost exclusively) your blue sensor ( and the green sensor very slightly).

So what will your brain make of that? Because there is some blue and some yellow, the green sensor will register some green because the 400THz is well within its filter passband and the blue sensor will see the Blue - so probably a greenish colour BUT also the Red sensor will detect a fair bit of that Yellow wavelength and the brain will interpret the colour (some red some green and some blue signals) as Green and White - or a de-saturated greenish colour.

The primary colours that are used in TV additive mixing are Red Green and Blue and you can obtain a whole range of perceived colours by using the appropriate quantities of each. If you want to understand paints etc. then search for Subtractive Colour Mixing, which is much more complicated and best avoided until you get the above.

danielhaish

## 1. What happens when two light waves with different frequencies meet?

When two light waves with different frequencies meet, they do not physically connect or merge with each other. Instead, they pass through each other and continue on their original paths. This is known as superposition, where the two waves combine to create a new wave with a different amplitude and frequency.

## 2. Can two light waves with different frequencies cancel each other out?

Yes, two light waves with different frequencies can cancel each other out through a process called destructive interference. This occurs when the peaks of one wave align with the troughs of the other wave, resulting in a net amplitude of zero. This can be observed in certain light phenomena, such as thin film interference.

## 3. Do the frequencies of the two light waves affect their interaction?

Yes, the frequencies of the two light waves play a crucial role in their interaction. When two waves with similar frequencies meet, they can constructively interfere and amplify each other, resulting in a brighter light. On the other hand, two waves with very different frequencies may not interact at all, or may only partially interfere with each other.

## 4. How do the frequencies of the light waves change after they meet?

The frequencies of the light waves do not change after they meet. Each wave maintains its original frequency, but the resulting wave may have a different frequency due to the superposition of the two waves. The frequency of the resulting wave depends on the frequencies and amplitudes of the two original waves.

## 5. Can two light waves with different frequencies create a new color when they meet?

Yes, when two light waves with different frequencies meet, they can create a new color through the process of color mixing. This occurs when the two waves have complementary colors, such as red and cyan, and combine to create a new color, such as white. This phenomenon is commonly observed in additive color mixing, where different colored lights are combined to create new colors.

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