Question

Consider the following reasons for the reddish appearance of the sun at the sunrise or the sunset:

The correct reasons are:

• A. i and iii only
• B. ii, iii, and iv
• C. i and ii only
• D. iii and iv only

Answer 1

The correct option is B

ii, iii, and iv

Scattering of light:

1. Light may be investigated completely from its own origination. Whenever light moves from one medium to another, such as air or a glass of water, a portion of the light is received by medium components, followed by subsequent radiation in a specific way, which is characterized as the scattering of light.
2. The bending of multicolored light can be seen in the afternoon due to the refraction and total internal reflection of light. The wavelength of the sunlight forms different colors in different directions.
3. Rayleigh's scattering theory is reasoned for the red color of the sun in the morning and the blue color of the sky.
4. Let $P$ be considered as the probability of scattering and $\lambda$ is the wavelength of radiation, then it is given as:

$\begin{array}{l}P\propto \frac{1}{{\lambda }^4}\end{array}$

Hence, the probability of scattering will be high for a shorter wavelength and it is inversely proportional to the fourth power of the wavelength of radiation.

1. The reddish appearance of the sun at sunrise or sunset is due to the scattering of light by the molecules of air and other fine particles present in the atmosphere.
2. At sunrise or sunset, the sun remains below the horizon, hence light from the sun passes through thicker layers of air and larger distances in the earth’s atmosphere before reaching our eyes.
3. The particulate in the atmosphere scatters the majority of the blue light rays and some other specific wavelengths of radiation. As a result, the only red light of a greater wavelength penetrates individuals, giving the sun a reddish look at sunrise or sunset.
4. Therefore, only red light, being of a higher wavelength reaches us which gives the reddish appearance of the sun at sunrise or sunset.

Therefore, option (B) is correct.