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प्रश्न
Why is the colour red used as a sign of danger?
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उत्तर
In the visible light, the wavelength of red light is longest, the light of red colour is scattered least by the air molecules of the atmosphere and therefore the light of red colour can penetrate to a longer distance. Thus, red light can be seen from the farthest distance as compared to the other colours having the same intensity. Hence, it is used for danger signal so that the signal may be visible from the far distance even in fog, etc.
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संबंधित प्रश्न
Which colour of white light travels fastest in glass?
In following diagram shows a thin beam of white light from a source S striking on one face of a prism.
What conclusion do you draw from the observation in part (b) above?
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Fig shows part of the arrangement for obtaining pure spectrum.
(a) Complete thediagram and show how to obtain a pure spectrum.
(b) What are the conditions necessary for obtaining a pure spectrum?
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Which colour has greater speed in glass?
