Which scientist first explained the dispersion of light?

Which of the following phenomena contributes significantly to the reddish appearance of the sun at sunrise or sunset?

Accommodation means the adjustment of light going into the eye for image formation.

What is meant by persistence of vision?

$A$ person is unable to read a book clearly when kept at a distance of $25 \,cm$ from his eye. Name the defect. How can it be corrected? Draw ray diagrams for $(i)$ defective eye $(ii)$ corrected eye and explain them.

How is astigmatism corrected?