Question

Hey Guys give answer of my question.

$\tt \: Give \: me \: Summary \\ \tt \: of \: the \: chapter \\ \tt "The \: Human \: Eye \: and \: Colour ful \: World".$
​

Answer 1

$\huge\textsf{\underline{\underline{\pink{Summary.}}}}$

$→\sf \: The \: ability \: of \: the \: eye \: to \: focus \:on \: both \: near \: and \: distant \\ \sf objects \: by \: adjusting \: its \: focal \: length, \: is \: called \\ \bf \red{the \: accomodation \: of \: the \: eye.}$

$→ \sf \: The \: smallest \: distance, \: at \: which \: the \: eye \\ \sf can \: see \: objects \: clearly \: without \: strain, \: is \\ \sf called \: \bf \red{the \: near \: point \: of \: the \: eye \: or } \\ \bf \red{ \: the \: least \: distance \: of \: distinct \: vision.} \\ \sf \: For \: a \: young \: adult \: with \: normal \: vision, \: it \\ \sf is \: about \: 25 \: cm.$

$→\sf \: The \: common \: refractive \: defects \: of \: the \\ \sf vision \: include \: \bf \red{myopia, \: hypermetropia} \: \sf and \\ \bf \red{ presbyopia.}$

$→ \sf \red{Myopia} \: (short\ - \: sightedness \: - \: the \\ \sf image \: of \: distant \: objects \: is \: focused \\ \sf before \: the \: retina) \: \sf it \: is \: corrected \: by \\ \sf using \: a \: concave \: lens \: of \: suitable \: power.$

$→ \sf \: The \: eye \: loses \: its \: power \: of \: accomodation \\ \sf at \: \bf \red{old} \sf \: age.$

$→ \sf \: The \: splitting \: of \: white \: light \: into \: its \\ \sf component \: colours \: is \: called \: \bf \red{dispersion.}$

$→\sf \red{Hypermetropia} \: (far \: - \: sightedeness \: - \: the \\ \sf image \: of \: nearby \: objects \: is \: focused \\ \sf beyond \: the \: retina) \: is \: corrected \: by \: using \\ \sf a \: convex \: lens \: of \: suitable \: power.$

$→\sf \: Scattering \: of \: light \: causes \: the \: blue \\ \sf colours \: of \: sky \: and \: the \: reddening \: of \: the \\ \sf sun \: at \: sunrise \: and \: sunset.$