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प्रश्न
Due to elongation of _______ and increase in curvature of the eye lens, a person cannot see distant objects clearly.
पर्याय
eyeball
pupil
eyelid
cornea
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उत्तर
Due to elongation of eyeball and increase in curvature of the eye lens, a person cannot see distant objects clearly.
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संबंधित प्रश्न
In a Std. X class out of 40 students 10 students use spectacles, 2 students have positive power and 8 students have negative power of lenses in their spectacles.
Answer the following questions:
(1) What does the negative power indicate?
(2) What does the positive power indicate?
(3) Generally which type of spectacles do most of the students use?
(4) What defect of eyesight do most of the students suffer from?
(5) Give two possible reasons for the above defect.
List three common refractive defects of vision. Suggest the way of correcting these defects.
Name the defect of vision in a person:
whose near point is more than 25 on away.
Name the defect of vision in a person:
whose far point is less than infinity
Which defect of vision can be rectified:
by using a convex lens?
What is the other name for
hypermetropia
Name any two defects of vision which can be corrected by using spectacles.
A man can read the number of a distant but clearly but he finds difficulty in reading a book.
From which defect of the eye is he suffering?
What are the two most common defects of vision (or defects of eye)? How are they corrected?
Name the defect of vision which can be corrected by a diverging lens. Show clearly by a ray diagram how the lens corrects the defect.
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 picture given here shows a person wearing 'half-moon' spectacles. What sort of eye-defect do do you think he has? Why are these particular spectacles useful to him?
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 an old man
Describe the mechanism of focusing the image of a distant object in your eye when you raise your head after reading a book.
By closing the eyes and gently pressing them by your palms, you may see some specks of brilliant light. How do you get this sensation while there is no light entering your eyes?
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 eye defect is hypermetropia? Describe with a ray diagram how this defect of vision can be corrected by using an appropriate lens.
Choose the correct answer :
Presbyopia is a disease of _____________
Name the common defects of the eye.
Name an old age eye defect. Why is it caused?
Give Reason:
Why do we see clearly in the central region of the retina?
Give Reason:
Deficiency of vitamin A causes night blindness.
Explain the Term: Hypermetropia
Explain the Term: Cataract
Give Technical Term:
The type of lens used to correct myopia is
Complete the following sentence with appropriate word :
An inability to focus on nearby objects due to loss of elasticity of the lens with age is called Iris.
With respect to human eye explain:
(i) How is the image formed on the retina?
(ii) How is the amount of light entering the eye-controlled?
(iii) What type of lens is used for the correction of ‘Long sight’ defect?
(iv) With the help of a ray, diagram show the defect of the eye and then its correction after the use of a lens.
Mention, if the following statement is True or False
Hypermetropia is a defect of the eye caused due to the eyeball elongation
In Myopia the human eye _______.
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.
A person cannot see distinctly objects kept beyond 2 m. This defect can be corrected by using a lens of power:
Assertion: Myopia is the defect of vision in which a person cannot see distant objects clearly.
Reason: This due to eye-ball being too short.
Correlate the given sequence:
Hypermetropia : Convex lens : ______ : Concave lens
Observe the figure whether it is correct or not and explain the phenomenon.
State reasons for Myopia. With the help of ray diagrams, show the:
- image formation by a myopic eye, and
- correction of myopia using an appropriate lens.
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 |
