Which colour of white light suffers $(i)$ least deviation and $(ii)$ maximum deviation when a beam of white light passes through a glass prism?

The focal length of the eye lens increases when eye muscles

$(a)$ Explain why the colour of a clear sky appears blue during the day with the help of a diagram.
$(b)$ Explain why the Sun looks reddish at the time of sunrise and sunset.

Account for the following:
$(a)$ Part of the human eye that helps in changing the focal length of the eye lens.
$(b)$ The condition resulting due to the eye lens becoming cloudy.
$(c)$ The factors on which the colour of the scattered white light depends.
$(d)$ The range of vision of a normal eye.
$(e)$ The sky appears dark to the astronauts in space.

Which part of the eye is responsible for adjusting the size of the pupil?

How is near-sightedness corrected?