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Why sky is blue?

The white light emitted by sun is a mixture of violet, indigo, blue, green, yellow, orange, red colours. The different coloured rays which are in the form of waves will have different wavelengths. The violet coloured light ray will have minimum wavelength where as the red colour will have maximum wavelength.

Light rays from the sun when they enter into earth's atmosphere which consists of nitrogen, oxygen atoms and dust particles and when the rays strike those atoms and particles, the blue colour having minimum wavelength will be scattered more in different directions. The blue colour will scatter more than red colour. This scattered blue colour appear to us as 'sky. In fact the wavelength of violet colour is less than that of blue colour and so the sky should appear as violet. But sky is not appearing with violet colour. Why? The reason is in while light emitted by sun the violet colour is in less content and more over our eye is more sensitive to blue colour than violet colour and the power of recognition is more for blue colour. During sunset, the sky is more blue because the ozone present the upper layers of atmosphere will completely absorb the red colour present in the light of the setting sun.

Laxmi... Emani
Published date : 14 Nov 2012 04:41PM

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