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Anuja Cannot See the Blackboard Writing but She Can See Nearby Things. (A) What is the Eye Defect She is Suffering From? (B) State the Possible Reason for Her Defect - Science and Technology 1

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प्रश्न

Anuja cannot see the blackboard writing but she can see nearby things.
(a) What is the eye defect she is suffering from?
(b) State the possible reason for her defect.
(c) How is it corrected

संक्षेप में उत्तर

उत्तर

(a) Anuja is suffering from a defect of vision called myopia (Near sightedness)
(b) The possible reason for her defect is the distance between the eye lens and retina increases as the eyeball is lengthened or lens is curved.
(c) It is corrected using spectacles having concave lenses of appropriate power.
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2016-2017 (July)

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संबंधित प्रश्न

What is the far point and near point of the human eye with normal vision?


Name the defect of vision in a person: 

 whose near point is more than 25 on away.  


 Which defect of vision can be rectified: 

by using a concave lens?


What is the scientific name of 

short-sightedness


What is the other name of old age hypermetropia?


Differentiate between myopia and hypermetropia. What type of spectacles should be worn by a person having the defects of myopia as well as hypermetropia? How does it help?


A person suffering from the eye-defect myopia (short-sightedness) can see clearly only up to a distance of 2 metres. What is the nature and power of lens required to rectify this defect?


 A person having short-sight cannot see objects clearly beyond a distance of 1.5 m. What would be the nature and power of the corrective lens to restore proper vision?


 What is long-sightedness? State the two causes of long-sightedness (or hypermetropia). With the help of ray diagrams, show:
(i) the eye-defect long-sightedness.
(ii) correction of long-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


Though a woman can see the distant object clearly, she cannot see the nearby objects clearly. She is suffering from the defect of vision called:
(a) long-sight
(b) short-sight
(c) hind-sight
(d) mid-sight


The defect of vision in which the eye-lens of a person gets progressively cloudy resulting in blurred vision is called:
(a) myopia
(b) presbyopia
(c) colourblindness
(d) cataract


A short-sighted person has a near point of 15 cm and a far point of 40 cm.
(a) Can he see clearly an object at a distance of:
(i) 5 cm?
(ii) 25 cm?
(iii) 50 cm?
(b) To see clearly an object at infinity, what kind of spectacle lenses does he need?


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?


A person can read a book clearly only if he holds it at an arm's length from him. Name the defect of vision:  

if the person is a young man 


Name the following:

The photosensitive pigment present in the rods of the retina.


Name an old age eye defect. What happens in it?


Enumerate the common defects of vision, their causes and the possible methods of correcting them.


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.


What is Hypermetropia (far sightedness)? 


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?


A student has difficulty reading the blackboard while sitting in the last row. What could be the defect the child is suffering from? How can it be corrected?


List two causes of presbyopia. Draw labelled diagram of a lens used for the correction of this defect of vision. 


When do we consider a student sitting in the class to be myopic? List two causes of this defect. Explain using a ray diagram how this defect of eye can be corrected.


Given below is a diagram depicting a defect of the human eye? Study the same and answer the question that follow:

Draw a labeled diagram to show how the above mentioned defect is rectified using the lens named above.


Have a look at the posture of this woman who is reading a book and answer the questions which follow:

What are the two conditions shown in sections A and B of the eye as applicable to her?


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?


Differentiate between:

Short-sightedness and Long-sightedness.


Differentiate between:

Myopia and Hypermetropia.


Explain the Term: Presbyopia


Study the following diagram carefully and then answer the questions that follow. The diagram is depicting a defect of the human eye :

(i) Identify the defect shown in the diagram.
(ii) Give two possible reasons for the above defect.


Given below is a diagram showing a defect of vision. Name the defect of vision and draw an accurately labelled diagram to correct this defect.


What are the causes of ‘Myopia’?


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 ______ ______

Given alongside is a diagram depicting a defect of the human eye. Study the same and answer the questions that follow:

  1. Name the defect shown in the diagram.
  2. Give two possible reasons for this defect.
  3. Name the parts labelled 1 to 4.
  4. Name the type of lens used to correct this eye defect.
  5. Draw a labelled diagram to show how the above mentioned defect is rectified using the lens named above.

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