Why does the sky appear blue? A). The color of the water is reflected in the sky B). Fine particles in the atmosphere scatter light of shorter wavelength C). The water molecules in the atmosphere make the sky appear blue D). None of these
Hint: You can start by defining the phenomenon of scattering as it is a key concept in this solution. Then describe among all the colors in the light coming from the sun, blue is scattered the most and hence the color of the sky is blue.
Complete step-by-step solution: We receive white light from the sun. White light is made up of all the existing colors. To understand why the sky appears blue we have to understand the phenomenon of scattering. Scattering – Scattering is the phenomenon in which a particle scatters EM rays that strike the particle when the wavelength of the EM wave is comparable to the size of the particle. The shorter the wavelength of the wave the more the scattering. Something similar happens when light from the sun enters our atmosphere. As we discussed before, the scattering of the light depends upon the wavelength of the light and the size of the particle causing the scattering. White light is composed of seven light and among them, blue light scatters the most as the wavelength of the blue light is comparable to the size of particles in the atmosphere. So, the sky appears blue. Hence, the sky appears blue because the fine particles in the atmosphere scatter light of shorter wavelengths. Hence, option B is the correct choice.
Note: You can also see the constituents of white light using a prism. When white light is passed through the prism it is split into what is called the VIBGYOR (representing violet, indigo, blue, green, yellow, orange, and red). You may have also seen this phenomenon during or just after a rain, this is why rainbows are formed. In the case of rainbows, white light interacts with small droplets of water and splits into its constituents namely the VIBGYOR.