Question

Reason for the blue colour of the sky is

• A. Dispersion of light
• B. Scattering of light
• C. Refraction of light
• D. Total internal reflection

Hint:

Remember:
• Blue sky $\rightarrow$ Rayleigh scattering.
• Red sunrise/sunset $\rightarrow$ Blue light is scattered away, leaving red light.
• Rainbow $\rightarrow$ Dispersion of light.

Answer 1

The Correct Option is B

Concept: The blue colour of the sky is due to the scattering of sunlight by the molecules of air present in the Earth's atmosphere. This phenomenon is known as Rayleigh scattering.

Step 1: Understand scattering of light.
Sunlight consists of seven colours. Among these colours, \[ \boxed{\text{Blue light has a shorter wavelength than red light.}} \] Shorter wavelengths are scattered much more than longer wavelengths.

Step 2: Reason for the blue sky.
As sunlight passes through the atmosphere,
• Blue light is scattered in all directions.
• Our eyes receive this scattered blue light.
• Hence, the sky appears blue.

Step 3: Analyse the options.

• Dispersion of light -- Separation of colours through a prism.
• Scattering of light -- Correct.
• Refraction of light -- Bending of light at the interface of two media.
• Total internal reflection -- Reflection occurring inside a denser medium.

Step 4: Final conclusion.
Therefore, the blue colour of the sky is due to \[ \boxed{\text{Scattering of light}.} \]