What is the other name of long-sightedness?

$A$ person is able to see objects clearly only when these are lying at distances between $50 \text{ cm}$ and $300 \text{ cm}$ from his eye. Identify the kind of defects of vision he is suffering from. Give reason for your answer.

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

$(a)$ Explain why the colour of a clear sky appears blue during the day with the help of a diagram.
$(b)$ Explain why the Sun looks reddish at the time of sunrise and sunset.

State the function of the pupil and ciliary muscles.

Which color of light is scattered the most due to the atmosphere?