CBSE Class 10 Answered

it is important for fog lights to be one color (rather than white, which is all colors) because the different
wavelengths(colors) of visible light scatter off the fog droplets differently. This phenomenon is known as "dispersion," because the different colors of light in an image will separate from each other, causing the image to "disperse." If you illuminate the road with only one wavelength (color) of light, the images of the objects you see will still become somewhat blurry because of the scattering of light by the fog, but at least you won't have extra problems from dispersion. So, if we want to use just one wavelength of light, which wavelength should we use? It turns out that light with short wavelengths scatters more than light with long wavelengths (short to long: violet, indigo, blue, green, yellow, orange, red). So, a long wavelength light will be best. There's another thing to
consider, too: our eyes are not equally sensitive to all colors. It turns out that we are most sensitive to yellow and green light. So, our best compromise between sensitivity for our eyes and a long wavelength for least scattering is yellow light.