Where is the image formed in an eye suffering from near-sightedness?

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

$A$ human eye can focus objects at different distances by adjusting the focal length of the eye lens. This is due to

$(a)$ Explain the phenomenon of scattering of light. State the factor on which the colour of scattered light depends.
$(b)$ List any two natural phenomena based on the scattering of light.

How is long-sightedness corrected?

An old person is unable to see clearly nearby objects as well as distant objects. $(i)$ What defect of vision is he suffering from? $(ii)$ What kind of lens will be required to see clearly the nearby as well as distant objects? Give reasons.