Why does the sun appear red at the sunrise?
During the sunrise, the light from the sun has to travel the longest distance of atmosphere to reach the observer. The light travelling from Sun loses blue light of short wavelength due to scattering, while the red light of long wavelength is scattered a little. So, there is not much loss. Thus, blue light is almost absent in sunlight reaching an observer and red light only reaches us. So, the sun is seen red.
i) Name a prism required for obtaining a spectrum of ultraviolet light.
ii) Name the radiation which can be detected by a thermopile.i) Quartz medium.
ii) Infrared radiations can be detected by thermopile.
i)
The diagram alongside shows a ray of light incident on an equilateral glass prism placed in minimum deviation position.
Copy the diagram and complete it to show the path of the refracted ray and the emergent ray.
ii) How are angle of incidence and angle of emergences related to each other in this position of the prism?
i) For the minimum deviation:
ii) Angle of incidence (i) = Angle of emergent (e)
Which colour of light travels fastest in any medium except air?
Red colour of light travels fastest in any medium except air.
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