Question

At sunrise or at sunset the sun appears to be reddish while at midday it looks white. Explain.

Answer 1

1. The scattering of light by tiny particles with regard to the wavelength of the incident light is known as Rayleigh scattering.
2. Light intensity is inversely proportional to the wavelength's fourth power.

$I=\frac{1}{{\lambda }^4}$

Where $I$ intensity of the light and $\lambda$is wavelength of the light.

1. Since the sun is at a greater distance from the earth's surface during sunrise and sunset, light rays should traverse a longer journey, in comparison to the middle of the day.
2. During dawn and sunset, red light has a longer wavelength and is less dispersed, thus it travels the greatest distance and reaches the earth's surface.
3. Since the sun is closer to the earth at midday, VIBGYOR light reaches the earth's surface and appears white.
4. The sun appears reddish at sunrise and sunset, but white in the middle of the day.