Question

A person cannot see the object beyond 3 m distinctly. State the nature and focal length of the Lens required to correct this defect of vision?

Answer 1

Answer:

nature of lens will be concave lens because it have the mypoia defect of vision..

please mark as brainlist

Answer 2

$\huge \bf{Solution.}$

Here, a person cannot see the object beyond 3

m. That means that he is suffering from myopia.

To correct this defect, a concave lens of will

be used which can form the image of an object

which is at infinite distance at 3m from eye.

Given, object distance,

$u = - \infty$

Image distance, v = –3 m = –300 cm (far point)

Focal length, f = ?

From lens formula,

$\frac{1}{v} - \frac{1}{u} = \frac{1}{f}$

$i.e. \frac{1}{ - 300} - \frac{1}{ - \infty } = \frac{1}{f}$

$\frac{1}{f} = \frac{1}{ - 300}$

$f = - 300 \: cm = - 3 \: m$

According to the sign of given focal length, the

lens is diverging in nature, i.e. it is a concave

lens.