What is the far point of a normal human eye?

Which color of light has the minimum velocity in a prism?

When you enter from bright sunshine into a dark room,you are not able to see clearly for some time. Why?

Explain the phenomenon of dispersion of white light through a glass prism,using a suitable ray diagram.

$(a)$ If a person wears a lens of power $-6\, D$ for distant vision and for correcting his near vision he needs a lens of $+2\, D$. Determine the focal length of the lenses in both the cases.
$(b)$ Give reasons for the following natural phenomena:
$(i)$ Stars twinkle.
$(ii)$ Planets do not twinkle.
$(iii)$ Stars appear raised in the sky.

Write the value of the near point of distinct vision for a normal eye.