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प्रश्न
Given alongside is a diagram depicting a defect of the human eye. Study the same and then answer the questions that follow:
(i) Identify the defect.
(ii) Name the parts labelled 1, 2 and 3.
(iii) Give labelled two possible reasons for this eye defect.
(iv) Draw a labelled diagram to show how the above mentioned defect is rectified.
उत्तर
(i) Myopia.
(ii) 1. Vitreous humor
2. Fovea
3. Optic nerve
(iii) 1. Lengthening of the eyeball from front to back.
2. Lens is too curved.
(iv) Correction of Myopia:
APPEARS IN
संबंधित प्रश्न
A person with a myopic eye cannot see objects beyond 1.2 m distinctly. What should be the type of the corrective lens used to restore proper vision?
Which defect of vision can be rectified:
by using a concave lens?
What is the other name for
myopia
A man can read the number of a distant but clearly but he finds difficulty in reading a book.
What type of spectacle lens should he use to correct the defect?
Explain with the help of labelled ray diagram, the defect of vision called myopia and how it is corrected by a lens.
What is short-sightedness? State the two causes of short-sightedness (or myopia). With the help of ray diagrams, show:
(i) the eye-defect short-sightedness.
(ii) correction of short-sightedness by using a lens.
The defect of vision which cannot be corrected by using spectacles is:
(a) myopia
(b) presbyopia
(c) cataract
(d) hypermetropia
Differentiate between members of the following pair with reference to what is asked in bracket.
Myopia and hyperopia (cause of the defect)
You do not enjoy watching a movie from a very short distance from the screen in a cinema hall. Why?
Have a look at the posture of this girl who is reading a book and answer the questions which follow:
Name the problem she is facing.
Distinguish between the following pair of words:
Myopia and hypermetropia
Solve the following question:
The near point of the eye of a person is 50 cm. Find the nature and power of the corrective lens required by the person to enable him to see clearly the objects placed at 25 cm from the eye?
Differentiate between:
Myopia and Hypermetropia.
Explain the Term: Hypermetropia
What type of lens is used to correct Astigmatism?
Correlate the given sequence:
Hypermetropia : Convex lens : ______ : Concave lens
Observe the figure whether it is correct or not and explain the phenomenon.
Observe the following diagram and answer questions following it:
- Identify the defect of vision shown.
- List its two causes.
- Name the type of lens used for the correction of this defect.
Complete the following table by observing the given figures:
| Figure → |  |
 |
| Points ↓ | ||
| (a) Name of the defect | ______ | ______ |
| (b) Position of the image | ______ | ______ |
| (c) Lens used to correct the defect | ______ | ______ |
Have a look at the posture of this girl who is reading a book and answer the questions which follow:
 |
- Name the problem she is facing.
- What are the two conditions shown in sections A and B of the eye as applicable to her.
- What kind of reading glasses does she need?
 |
 |
| A | B |
