(a) Explain why colour of clear sky appears blue during the day with the help of diagram.
(b) Explain why Sun looks reddish at the time of sun rise and sun set.
(a) The size of dust particles is comparable to the wavelength of blue colour so these are scattered most and enter our eyes.
(b) At the time of sun rise or sun set sun is near the horizon and sun rays have to travel a larger distance in this way all colours get scattered only the red colour which is of longest wavelength reaches the observer hence sun appears reddish at sun rise and at sunset.
