Question

The clear sky appears blue because

• A. blue light gets absorbed in the atmosphere
• B. ultraviolet radiations are absorbed in the atmosphere
• C. violet and blue lights get scattered more than lights of all other colours by the atmosphere
• D. light of all other colours is scattered more than the violet and blue colour lights by the atmosphere

Answer 1

The correct option is C

violet and blue lights get scattered more than lights of all other colours by the atmosphere

Explanation for the correct option:

Option C:

1. Whenever light enters the Earth's atmosphere, it scatters.
2. The intensity of scattering depends on the size of dust particles in the air and the wavelength of the light.
3. The intensity of scattering is given by Rayleigh's law of scattering: $Amountofscattering=\frac{1}{{\lambda }^4}$(where $\lambda$ is the wavelength.)
4. The wavelength of the colour spectrum increases in the order: violet, indigo, blue, green, yellow, orange, red.
5. As the colors violet and blue have the least wavelength, they will scatter the most.
6. Hence, the sky appears blue.

Therefore, option C is the correct option.