Which of the following statements is correct?

$A$ student finds the writing on the blackboard blurred and unclear while sitting on the last desk in a classroom. He,however,sees it clearly while sitting on the front desk at about $2\, m$ from the blackboard.
$(a)$ Draw ray diagrams to illustrate the formation of image of the blackboard writing by his eye lens when he is seated at the $(i)$ last desk,$(ii)$ front desk.
$(b)$ Name the defect of the eye from which the student is suffering.
$(c)$ Name the kind of lens that would help him to see clearly even when he is seated at the last desk. Draw a ray diagram to illustrate how this lens helps him to see clearly.

What is meant by the near point of the eye?

What happens to the lens and the ciliary muscles when you are looking at distant objects?

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

$(a)$ State the reasons which lead to hypermetropia. With the help of suitable diagrams,explain this defect of vision and its correction.
$(b)$ Draw a diagram of an experimental arrangement for observing the scattering of light in a colloidal solution. Name the two chemicals used in this activity.