Which of the following are the primary colours of light?

In the dispersion of white light by a prism,which color of light undergoes the maximum deviation?

Why can you not see an object clearly if it is placed very close to your eye?

$(i)$ 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?

Accommodation means the adjustment of light going into the eye for image formation.

What is the least distance of distinct vision of a normal human eye (in $cm$)?