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

$(a)$ Explain the following terms used in relation to defects of vision and corrections provided for them:
$(i)$ Myopia $(ii)$ Astigmatism $(iii)$ Bifocal lenses $(iv)$ Far-sightedness (Hypermetropia).
$(b)$ Describe with a ray diagram how a person with myopia can be helped by spectacles.

When white light is incident on a yellow pigment,which colors of light are reflected?

Why do we see a rainbow in the sky only after rainfall?

What is the time difference between the actual sunset and the apparent sunset?

When blue and green light overlap,what color does that region appear?