Question

Blue colour of the sky is due to the scattering of light by the molecules of

• A. \(H_2\)
• B. \(H_2O\)
• C. \(CO_2\)
• D. \(N_2\) and \(O_2\)

Answer 1

The Correct Option is D

The blue colour of the sky is primarily due to a phenomenon known as Rayleigh scattering, which occurs when sunlight interacts with the molecules in the atmosphere. This scattering is significantly influenced by the presence of gases such as nitrogen (\(N_2\)) and oxygen (\(O_2\)).

Sunlight is composed of a spectrum of colours, each with different wavelengths. Blue light has a shorter wavelength compared to other visible colours, such as red or yellow. According to Rayleigh's scattering law, the amount of scattering is inversely proportional to the fourth power of the wavelength. This means that shorter wavelengths are scattered more than longer wavelengths.

The small molecules of \(N_2\) and \(O_2\) in the atmosphere scatter the shorter blue wavelengths of sunlight in all directions, making the sky appear blue from every direction we look.

In conclusion, the blue colour of the sky is due to the scattering of light primarily by the molecules of nitrogen (\(N_2\)) and oxygen (\(O_2\)).

Answer 2

The blue colour of the sky is due to a phenomenon called Rayleigh scattering.

When sunlight enters the Earth's atmosphere, it interacts with molecules and tiny particles in the air.

The smaller molecules\( \mathbf{N_2} \) (Nitrogen) and \( \mathbf{O_2} \) (Oxygen) are most effective at scattering shorter wavelengths of light, such as blue and violet.

Though violet is scattered more, our eyes are more sensitive to blue and the upper atmosphere absorbs some violet light, so the sky appears blue.

Final Answer: \( \mathbf{N_2} \) and \( \mathbf{O_2} \)