Question

The blue colour of the sky is due to the phenomenon of

• A. scattering
• B. dispersion
• C. reflection
• D. refraction.

Answer 1

The Correct Option is A

The blue color of the sky is primarily due to the phenomenon of scattering. Let's explore the detailed reasoning behind this:

1. Understanding Scattering:
   • Scattering is a process where small particles or molecules cause light to deviate from its original path.
   • The amount of scattering is inversely proportional to the wavelength of light, meaning that shorter wavelengths scatter more than longer wavelengths.
2. Why the Sky Appears Blue:
   • White sunlight is composed of different colors, each with different wavelengths. Among these, blue has a shorter wavelength compared to other colors like red and yellow.
   • When sunlight enters Earth's atmosphere, it collides with air molecules. Due to its shorter wavelength, blue light is scattered in all directions by the atmospheric particles. This scattering causes the sky to appear blue from most angles.
3. Elimination of Other Options:
   • Dispersion: While dispersion also involves the separation of light into different colors, it primarily explains phenomena like rainbows, where light is split in a more orderly fashion rather than scattered.
   • Reflection: Reflection involves light bouncing off surfaces, which is different from scattering which occurs within the substance (the atmosphere in this case).
   • Refraction: Refraction is the bending of light when it passes through a medium with a different density, not the scattering of light by particles.
4. Conclusion: The scattering of shorter blue wavelengths of light is much more extensive than the scattering of longer red or orange wavelengths, making the blue light more prominent when we look at parts of the sky away from the sun.

Hence, the correct answer is scattering.