Light rays entering the eye are refracted by the lens and form an image on a specific part of the eye. What is this part called?

Which of the following two colors are complementary colors?

$A$ child sitting in a classroom is not able to read clearly the writing on the blackboard.
$(a)$ Name the type of defect from which his eye is suffering.
$(b)$ With the help of a ray diagram show how this defect can be remedied.

Which of the following is not a secondary color?

How can you identify the type of vision defect a person is suffering from by physically touching their spectacles?

What is meant by accommodation of the eye?