What is the lens-like structure present in the eye called?

Explain the phenomenon of dispersion of white light through a glass prism,using a suitable ray diagram.

Which part of the eye controls the amount of light entering it?

Which of the following is not a primary color of light?

When do we consider a person to be myopic or hypermetropic? Explain using diagrams how the defects associated with myopic and hypermetropic eye can be corrected?

$(i)$ Calculate the maximum power of accommodation of a person having normal vision.
$(ii)$ $A$ person needs to use glasses for reading a newspaper. Identify the defect in her vision and the type of lens she would need to correct it.
$(iii)$ Sometimes when we enter a dark room from bright sunlight,we are unable to see objects clearly. Why?