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Why the Danger Signals are red in Colour ?

Asked by Abhishek Padhy(KENDRIYA VIDYALAYA NO.3) , on 11/1/11


Hi Abhishek!

Please refer to the answer given by Soorampalli.

All of you have done a good work!! Keep posting!!


Posted by Ajay T.s.on 12/1/11

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That red light is scattered the least by air molecules. The effect of scattering is inversely related to the fourth power of the wavelength of a color. Therefore blue which has the least wavelength of all the visible radiations is scattered the most and red which has the highest wavelength of all the colors we can see is scattered the least. So red light is able to travel the longest distance through fog, rain, and the alike. Also, red is a color we inherently perceive as one that is associated with danger. I guess it has been genetically programmed as hot objects are red in color and also red is the color of blood. These reasons make danger signals the most effective when they are painted in red.


Posted by Chandnion 11/1/11


red colour has highest wavelength and is least scattered by fog ,etc. this property makes it possible to see signal from far distances

Posted by Mariam Hamsheeda(AJISSES,Kasargod) on 11/1/11


 Red colour is used in danger signals due to the following reasons -

1. Wavelength of RED colour is most in the VIBGYOR series. If wavelength is more, it is less scattered.

2. It is least scattered by other particles like fog,smoke. As it is least scattered , less light deviates from its original path. Hence more light reflects back and reaches our eyes. Hence we can see RED colour properly even on a foggy day.

Posted by Manish Dash(K V J N U) on 11/1/11

red colour is least scattered by fog mist or dust and is of longer wavelengths hence guring emergencies it bcomes easy to spot the colour and do the needful  !!

Posted by Kamil Hasanon 11/1/11

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