Science
Give reasons for the following :
(a) Danger signals installed at airports and at the top of tall buildings are of red colour.
(b) The sky appears dark to the passengers flying at very high altitudes.
(c) The path of a beam of light passing through a colloidal solution is visible.
Spectrum
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Answer
(a) Red colour has the longest wavelength and it deviates the least, hence, danger signals installed at airports and at the top of tall buildings are of red colour so that they can be easily seen from a distance.
(b) Scattering of light takes place because of the particles present in the atmosphere. At high altitude, the atmospheric medium is rarer so the scattering of light taking place is very low. Hence, the sky appears dark to passengers flying at high altitudes.
(c) The path of a beam of light passing through a colloidal solution is visible due to scattering of light by colloidal particles and this is known as Tyndall effect.
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