Question

State the difference in colours of the sun observed during sunrise/sunset and noon. Give explanations for each.

Answer 1

It is based on the phenomenon in which the light rays coming from the sun get deviated from its straight-line path after striking the various particles suspended in the atmospheric. The degree of deviation depends upon the wavelength of the light.

Complete answer:
In the given question, we are asked the difference in colours during the sunrise/sunset and the noon.We are asked to find the reason for these phenomena.To begin with, we must have observed that during the sunrise in the early morning the sun appears to be reddish. This may be due to the fact that all the different colours are associated with different wavelengths. Since, the wavelengths are associated with the energies of that corresponding colour. The equation which gives the relation between the energy and the wavelength is given below:
$E = \dfrac{{hc}}{\lambda }$
Where,
$E$ indicates the energy of that particular colour.
$h$ indicates Planck’s constant.
$c$ indicates speed of light.
$\lambda$ indicates the wavelength of the light of that particular colour.
It indicates that energy is inversely proportional to the wavelength of the light, which means higher is the energy, lower is its wavelength, or vice-versa.The light spectrum is commonly known as VIBGYOR, which gives the sequence of decreasing order of energies of the spectrum. It indicates that blue light has the highest energy while the red light has lowest energy. Then we can say that the wavelength of the blue light is the shortest while the longest wavelength is for the red light.At sunrise we see the sun reddish in colour, which is due to scattering of light. This is the phenomenon in which the light rays get deviated from the straight in which it was moving, after striking an obstacle like dust particles, atmospheric water vapour molecules, etc.Since, the red light has the longest wavelength, it can travel a longer distance while the blue light gets scattered off due to its shorter wavelength.
At noon, we observe white light from the sun. This is because the sun at noon is nearly overhead. The sunlight which passes through the atmosphere suffers less scattering because the light rays have to pass through less portion of atmosphere.

Note: It is important to note that red light has lowest energy while blue light has the highest. The red light has a larger wavelength for which it is used in tail lights of vehicles so that they can be seen from a large distance to avoid collisions. White light is the mixture of all the colours.