What is the near point of a normal human eye (in $cm$)?

Study the diagram given below and answer the questions that follow it.
$(i)$ Identify the defect of vision represented in this case. Give a reason for your answer.
$(ii)$ Mention the two causes of this defect.

What is the time difference between the actual sunset and the apparent sunset?

$A$ narrow beam $PQ$ of white light is passing through a glass prism $ABC$ as shown in the diagram.
Trace it on your answer sheet and show the path of the emergent beam as observed on the screen $DE$.
$(i)$ Write the name and cause of the phenomenon observed.
$(ii)$ Where else in nature is this phenomenon observed?
$(iii)$ Based on this observation,state the conclusion which can be drawn about the constituents of white light.

Name the colours of the visible spectrum.

$(i)$ 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?