Multiple choice

The sky of the earth appears to be blue because of ____.

  1. reflection

  2. scattering

  3. interference

  4. diffraction

Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Blue light is scattered most by air molecules due to Rayleigh scattering (scattering intensity ~1/λ^4). Reflection would bounce light back unchanged, while interference and diffraction don't cause the sky's blue color.