Short-sightedness (myopia) is caused due to the elongation of the eyeball.

For which of the following cases is total internal reflection of light possible?

Which part of the eye is responsible for changing the focal length of the eye lens by adjusting its thickness?

Explain the following terms connected with the eye:
$(i)$ Ciliary muscles
$(ii)$ Accommodation
$(iii)$ Blind spot.

$A$ 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.

The peacock blue color is formed by the superposition of which two colors of light?