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प्रश्न
The danger signal is red. Why?
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उत्तर
Since the wavelength of red light is the longest in the visible light, the light of red colour is scattered the 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 other colours of same intensity. Hence it is used for danger signal so that the signal may be visible from the far distance.
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संबंधित प्रश्न
Why does the sun seem to rise two minutes before the actual sunrise and set two minutes after the actual sunset ? Explain with the help of labelled diagram.
We can see the sun before the actual sunrise by about:
(a) 5 minutes
(b) 2 minutes
(c) 2 hours
(d) 20 minutes
State whether the following statements are true or false:
The scattering away of blue light makes the sun appear red at sunset.
Why does the sky appear dark (or black) to an astronaut instead of blue?
Draw a neat and labelled diagram of the experimental set up for observing the scattering of light in a colloidal solution of sulphur to show how the sky appears blue, and the sun appears red at sunrise and sunset.
Which component of sunlight is scattered away when the sun appears red at sunrise or sunset?
In an experiment to study the scattering of light by passing a beam of white light through a colloidal solution of sulphur in a transparent glass tank:
Which colour is observed from the sides of the glass tank? Does this colour correspond to the colour of sky on a clear day or the colour of sky around the sun at sunset?
When sunlight enters the earth’s atmosphere, state which colour of light is scattered
- the most and
- which the least.
To an astronaut in a space-ship, the earth appears ______.
The bluish colour of water in deep sea is due to ____________.
