Question

Sky to appear blue due to
1. Diffraction of light
2. Scattering of light
3. Internal reflection of light
4. Refraction of light
5. None of the above/More than one of the above.

Answer 1

Correct Answer - Option 2 : Scattering of light

The correct answer is the Scattering of light.

• Scattering of light is the Reason for the sky to appear blue.

• The sunlight that reaches the earth’s atmosphere is scattered in all directions by the gases and dust particles present in the atmosphere.
  • The blue colour is scattered more and hence the sky appears blue.
  • The reason for more scattering of blue colour is that the wavelength of the blue light is shorter than the other light.
  • So blue light is scattered in all directions by the tiny molecules of air in Earth’s atmosphere.
  • This is the reason sky appears blue.
• Scattering, in physics, is a change in the direction of motion of a particle because of a collision with another particle.

Process	Description	Examples
Scattering of light	A change in the direction of motion of a particle because of a collision with another particle.	The red colour of the sun at sunrise and sunset. The white colour of the sky at noon. The blue colour of the sky. The red colour is used as a danger signal.
Diffraction of light	The spreading of waves around obstacles.	From the shadow of an object. CD reflecting rainbow colours. Holograms
Internal reflection of light	Complete reflection of a ray of light within a medium such as water or glass from the surrounding surfaces back into the medium.	The formation of a mirage. Shining of the empty test tube in water. The shining of a crack in a glass-vessels. Parking of a diamond
Refraction of light	It passes from one transparent substance into another.	A coin at the bottom of the vessel filled with water appears slightly raised above its actual position due to the refraction of light.