The light when enters the human eye experiences most of the refraction while passing through

Calculate the focal length of a reading glass of a person if his distance of distinct vision is $ 75 \ cm $. (in $cm$)

When objects at different distances are seen by the eye,which of the following remains constant?

The near point of a hypermetropic person is $75\, cm$ from the eye. What is the power of the lens required to enable the person to read clearly a book held at $25\, cm$ from the eye?

$A$ person uses a lens of power $+3 \text{ D}$ to normalize vision. The near point of the hypermetropic eye is ....... $m$.

The least distance of distinct vision for a long-sighted person is $x \ m$. He wants to read a newspaper placed at a distance $(x/2) \ m$. The power of the spectacle lens used by him is $x \ D$. What is the value of $x$?