Question

when the sun rise and set it appears red. why?

Answer 1

It is due to the refraction of light and Red colour has more frequency so all the colour are hidden and we can see the Red colour with our naked eye .
I hope u get the answer

Answer 2

$\huge\mathfrak{Reason}$

This is because the sun remains low at the atmosphere around the horizon so the light coming from it gets to travel a long distance. So we only see the strongest color or with highest wavelength colour that's red . Thus sun appears red.