Question

Why does the sky appear blue from the earth's surface?

• A. When sunlight enters the atmosphere, fine air particles scatter all the colours other than the blue colour thus the blue colour reaches our eyes.
• B. When sunlight enters the atmosphere, fine air particles scatter blue colour more than red. The scattered blue light enters our eyes.
• C. When sunlight passes through the atmosphere, the blue light gets dispersed the most.
• D. None of these.

Answer 1

The correct option is B When sunlight enters the atmosphere, fine air particles scatter blue colour more than red. The scattered blue light enters our eyes.

The main phenomenon behind the colour of the sky is due to scattering. When sunlight passes through the atmosphere, the fine particles in the air scatter the blue colour (shorter wavelengths) more strongly than red. The scattered blue light enters our eyes. If the earth had no atmosphere, there would not have been any scattering.