English, asked by Maheshgaud, 1 year ago

A person far point is 2 m and his near point is 50 cm . Find the nature, focal length and power of the lenses he must use to (a). See distant objects and (b) read a book clearly. The least distance of distinct vision is 25 cm.

Answers

Answered by BrainlyWarrior
16
\textbf{Hey there}!


\textbf{Solution}:



( A ). To see distant objects :


The distance of the far point ( x ) = 2 m.


Where m is metre.


The defect can be corrected by using concave lens of focal length,


f = - x = - 2 m.


The power of the lens is given by :


P = \frac{1}{f ( in m )}


= \frac{ 1}{-2}


= \textbf{- 0.5 D}


( B ). To read a book :


Here D = 25 cm.


The distance of a near point ( x ) = 50 cm.


Where cm is centimetre.


The defect can be corrected by using convex lens of focal length:


f = \frac{x D}{x - D}


= \frac{50 × 25}{50 - 25}


= 50 cm.


The power of the lens given by:

P = \frac{1}{f ( in m )}


= \frac{1}{0.5}


= \textbf{+ 2 D}




#Be Brainly.

Answered by THEmultipleTHANKER
1

(a)-0.5D \\ (b)+2D

Answered by THEmultipleTHANKER
1

(a)-0.5D \\ (b)+2D

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