Name: Eye: Structure and Parts
Uploaded: 2019-07-19
Duration: 5 min 36 s
Description: Do you know that eye is a powerful optical instrument or a camera? But it works using living cells. How does it process light energy? Curious! Don't wait, Get in!

Question

Draw the ray diagram to show how hypermetropia is corrected.Make a diagram to show how hypermetropia is corrected. The near point of a hypermetropic eye is

1 m

. What is the power of the lens required to correct this defect? Assume that the near point of the normal eye is

0.25 m

.

Accepted Answer

A person suffering from hypermetropia can see distinct objects clearly but faces difficulty in seeing nearby objects clearly.It happens because the eye lens focuses the incoming rays beyond the retina. This defect of vision is corrected by using a convex lens of suitable power.

The given individual will be able to clearly see the object kept at $25 cm$ (near point of the normal eye) if the image of the object is formed at his near point, which is given as $1 m$ .

Therefore, object distance, $u = - 25 cm$
Image distance, $v = - 100 cm$

Using lens formula, $\frac{1}{v} - \frac{1}{u} = \frac{1}{f} \Rightarrow - \frac{1}{100} - \frac{1}{- 25} = \frac{1}{f} \Rightarrow \frac{1}{f} = \frac{4 - 1}{100} \Rightarrow f = 33.3 cm = 0.33 m$

Power of lens, $P = \frac{1}{f} = \frac{1}{0.33} = + 3 D$

Hence, power of the lens, $P = \frac{100}{f (cm)} = \frac{100}{\frac{100}{3}} = + 3 D$
Convex lens of power $3 D$ should be used.

Draw the ray diagram to show how hypermetropia is corrected.Make a diagram to show how hypermetropia is corrected. The near point of a hypermetropic eye is $1 m$ . What is the power of the lens required to correct this defect? Assume that the near point of the normal eye is $0.25 m$ .

Important Questions on The Human Eye and the Colourful World

Learn and Prepare for any exam you want !

Draw the ray diagram to show how hypermetropia is corrected.Make a diagram to show how hypermetropia is corrected. The near point of a hypermetropic eye is 1 m. What is the power of the lens required to correct this defect? Assume that the near point of the normal eye is 0.25 m.

Important Questions on The Human Eye and the Colourful World

Learn and Prepare for any exam you want !

Draw the ray diagram to show how hypermetropia is corrected.Make a diagram to show how hypermetropia is corrected. The near point of a hypermetropic eye is $1 m$ . What is the power of the lens required to correct this defect? Assume that the near point of the normal eye is $0.25 m$ .