Question

The sky appears blue due to:
A. Reflection of light
B. Dispersion and scattering of light
C. Total internal reflection of light
D. Blue color of water droplets

Answer 1

Hint: The tiny gas molecules of the Earth’s atmosphere scatter the sunlight in random directions. The amount of scattered light is large for shorter wavelengths.

Complete step-by-step answer:
The gas molecules, present in the atmosphere, have much smaller size than the wavelength range of visible light. The wavelength of light is larger in the red side of the visible spectrum whereas the blue side has shorter wavelengths. The molecules scatter smaller wavelengths in large amounts. This is in accordance with Rayleigh’s scattering theory which suggests that the amount of scattered light is inversely proportional to the fourth power of the wavelength of light.
Therefore, blue and violet lights are scattered more than red light. Sunlight contains more blue light than violet and the human eye is more susceptible to the blue color. As a result, the sky appears blue rather than violet although it has an even shorter wavelength.
Hence, the correct option is: (B) Dispersion and scattering of light.

Note:- Gas molecules of the atmosphere scatter light rays of shorter wavelengths in random directions. Although violet light has a shorter wavelength than blue, the human eye is compatible with the blue color. Also, the amount of blue light is more in sunlight than that of violet. Hence, the sky appears blue.