What happens when white light is incident on a white object?

In the eye of a person suffering from myopia (nearsightedness),where is the image of a distant object formed?

How does atmospheric refraction take place? Why do stars twinkle,but planets do not?

Why do we observe differences in the colours of the sun during sunrise,sunset,and noon?

Which optical phenomenon is responsible for the early sunrise and delayed sunset?

$A$ student cannot read properly from the blackboard while sitting on the front desk in a large classroom. However,he can read clearly while sitting on the last desk of the classroom.
$(a)$ Draw ray diagrams to illustrate the formation of the image of the blackboard writing by his eye lens when he is seated at the $(i)$ front desk,$(ii)$ last desk.
$(b)$ Name the defect of the eye from which the student is suffering.
$(c)$ Name the type of lens that would enable him to see the blackboard writing clearly when seated at the front desk. Draw a ray diagram to illustrate how this lens helps him to see clearly.