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प्रश्न
A student sitting at the back of the classroom cannot read clearly the letters written on the blackboard. What advice will a doctor give to her? Draw ray diagram for the correction of this defect.
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उत्तर
Since, the student sitting at the back of the classroom cannot read clearly the letters written on the blackboard, it means the student is suffering from Myopia. The doctor will suggest her, a concave lens of suitable power which will bring the image back on retina and therefore the defect will be corrected.
The ray diagram for the correction of this defect is as below :
Correction for Myopia
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संबंधित प्रश्न
List three common refractive defects of vision. Suggest the way of correcting these defects.
What is the far point and near point of the human eye with normal vision?
Explain two possible reasons of myopia. How can it be corrected? Explain with a suitable diagram.
The kind of lens required to correct Myopia
What is the scientific name of
long-sightedness?
Name any two defects of vision which can be corrected by using spectacles.
Your friend can read a book perfectly well but cannot read the writing on blackboard unless she sits on the front row in class.
Is she short-sighted or long-sighted?
An eye has a near point distance of 0.75 m. What sort of lens in spectacles would be needed to reduce the near point distance to 0.25 m? Also calculate the power of lens required. Is this eye long-sighted or short-sighted?
The near point of a long-sighted person is 50 cm from the eye.
(a) Can she see clearly an object at:
(i) a distance of 20 cm?
(ii) at infinity?
Given below is a diagram depicting a defect of the human eye. Study the same and answer the question that follow:
Name the defect shown in the diagram.
Observer the following diagram and answer the questions.
a) Which eye defect is shown in this diagram?
b) What are the possible reasons for this eye defect?
c) How this defect is corrected, write it in brief?
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.
Have a look at the posture of this woman who is reading a book and answer the questions which follow:
What kind of looking glasses she needs?
Explain the Term: Presbyopia
Explain the Term: Astigmatism
Explain the Term: Cataract
Given below is a diagrammatic representation of a defect of the human eye:
(i) Identify the defect.
(ii) Mention two reasons for the above defect.
(iii) State how the defect can be rectified.
(iv) Name the part of the eye responsible for maintaining the shape of the eyeball.
Nearsightedness : concave lens : : farsightedness : _______
Which of the following statement is correct?
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 |
