What is the other name of near-sightedness?

With the help of a diagram,explain the formation of a rainbow in the sky.

How is the eye lens held in its position?

What is the central aperture of the eye located behind the cornea called?

$A$ person needs a lens of power $-0.5 \text{ D}$ for correcting his distant vision. For correcting his near vision,he needs a lens of power $+1.5 \text{ D}$. What is the focal length of the lens required for correcting his $(i)$ distant vision,$(ii)$ near vision?

When white light is incident on an object and it absorbs all the component colors and reflects none of them,what color does the object appear to be?