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Question
Observe the figure whether it is correct or not and explain the phenomenon.
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Solution
The figure shows a myopic eye, in which the eye lens is unable to focus the light rays coming from distant objects into the retina. In this defect, the image of a distant object is formed before the retina i.e., the light rays converge before the retina. Hence, to correct the defect a diverging lens (concave lens) of proper focal length is used, so that after refraction rays reach to retina and the person can see the image clearly.
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RELATED QUESTIONS
What is myopia?
Millions of people in the developing countries of the world are suffering from corneal blindness. These persons can be cured by replacing the defective cornea with the cornea of a donated eye. A charitable society of your city has organised a campaign in your neighbourhood in order to create awareness about this fact. If you are asked to participate in this mission, how would you contribute in this noble cause?
(i) State the objective of organising such campaigns.
(ii) List two arguments which you would give to motivate the people to donate their eyes after death.
(iii) List two values which are developed in the persons who actively participate and contribute in such programmes.
The far point of a myopic person is 80 cm in front of the eye. What is the nature and power of the lens required to correct the problem?
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What is the scientific name of
short-sightedness
Name the defect of vision which makes the eye-lens cloudy resulting in blurred vision.
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Name an old age eye defect. What happens in it?
Describe the mechanism of focusing the image of a distant object in your eye when you raise your head after reading a book.
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.
A person is unable to read a book placed closer than 1 meter from his eyes. Identify the defect of vision in his eyes. Draw the ray diagrams to show the defect of vision and its correction.
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Draw a ray diagram to show how Hypermetropia is defect can be corrected using a lens.
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Distinguish between the following pair of words:
Myopia and hypermetropia
Given alongside is a diagram depicting a defect of the human eye. Study the same and then answer the questions that follow:
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Given below is a diagram depicting a defect of the human eye? Study the same and answer the question that follow :
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Explain the Term: Astigmatism
Give Technical Term:
The type of lens used to correct myopia is
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(ii) How is the amount of light entering the eye-controlled?
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(iv) With the help of a ray, diagram show the defect of the eye and then its correction after the use of a lens.
Nearsightedness: elongated eyeball : : farsightedness: _______
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Assertion: Concave mirrors are used as reflectors in torches, vehicle head lights and in search lights.
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Match the following:
| Column - I | Column - II |
| 1. Retina | a. Path way of light |
| 2. Pupil | b. Far point comes closer |
| 3. Ciliary muscles | c. near point moves away |
| 4. Myopia | d. Screen of the eye |
| 5. Hypermetropia | e. Power of accommodation |
