Our colour vision relies precisely on this. We have three sets of receptors that have varying sensitivities over the range of visible radiation and our brain takes in the combination of outputs from the three sensors and 'categorises' them into colours (Search Tristimulus Colour Vision theory"). The sensitivity of the sensors to wavelengths corresponding to Violet is very low (it's right on the 'skirts' of sensitivity). Also, the spectrum of Sunlight is relatively low in Violet content so we just don't care too much about Violet (in a manner of speaking) and doesn't discriminate too much. If you change the amount of the 'violet wavelengths' in the light entering the eye, it will make very little difference to the perceived colour; the colour that the brain assigns to what is seen.sunmoon said:And why different light waves having different intensity produce different sensation in our eyes?
The sky appears blue because of a phenomenon called Rayleigh scattering. This is when particles in the Earth's atmosphere, such as nitrogen and oxygen molecules, scatter sunlight in all directions. Blue light has shorter wavelengths, so it is scattered more easily, making the sky appear blue to our eyes. Violet light has even shorter wavelengths and is scattered even more, but our eyes are not as sensitive to violet light, so we see blue instead.
Yes, the sky can appear violet, especially during sunrise and sunset. This is because the angle of the sun's rays causes more red and orange light to be scattered, making the sky appear more violet.
The amount of water vapor and other particles in the atmosphere can affect the color of the sky. On clear days with low humidity, there are fewer particles in the air, causing the sky to appear a deeper blue. On cloudy or hazy days, there are more particles in the air, causing the sky to appear less blue.
The color of the sky can vary on other planets depending on their atmospheric composition and the distance from their sun. For example, Mars has a thin atmosphere with a high concentration of dust particles, causing its sky to appear reddish. Uranus has a blue-green sky due to the high concentration of methane gas in its atmosphere.
Human activities, such as air pollution, can affect the color of the sky. Pollutants in the air can scatter light differently, causing the sky to appear hazy or discolored. This is especially noticeable in cities with high levels of air pollution. However, these effects are temporary and do not significantly alter the natural color of the sky.