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Question
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
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Solution
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RELATED QUESTIONS
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.
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.
A student suffering from myopia is not able to see distinctly the objects placed beyond 5 m. List two possible reasons due to which this defect of vision may have arisen. With the help of ray diagrams, explain
(i) why the student is unable to see distinctly the objects placed beyond 5 m from his eyes.
(ii) the type of the corrective lens used to restore proper vision and how this defect is corrected by the use of this lens.
(b) If, in this case, the numerical value of the focal length of the corrective lens is 5 m, find the power of the lens as per the new Cartesian sign convention
Explain two possible reasons of myopia. How can it be corrected? Explain with a suitable diagram.
Which defect of vision can be rectified:
by using a convex lens?
Name the defect of vision in which the eye-lens loses its power of accommodation due to old age.
Name the defect of vision which makes the eye-lens cloudy resulting in blurred vision.
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?
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?
Describe the mechanism of focusing the image of a distant object in your eye when you raise your head after reading a book.
A person cannot read newspaper placed nearer than 50 cm from his eyes. Name the defect of vision he is suffering from. Draw a ray diagram to illustrate this defect. List its two possible causes. Draw a ray diagram to show how this defect may be corrected using a lens of appropriate focal length.
State one role of ciliary muscles in the human eye.
What eye defect is hypermetropia? Describe with a ray diagram how this defect of vision can be corrected by using an appropriate lens.
Draw a ray diagram to show how Hypermetropia is defect can be corrected using a lens.
List two causes of presbyopia. Draw labelled diagram of a lens used for the correction of this defect of vision.
Select the odd one in the following series:
Endolymph, Tympanic membrane, Semi-circular canal, Blind spot.
Name the common defects of the eye.
Name an old age eye defect. Why is it caused?
Give Technical Term:
The path which responsible for protecting the eye from sweat.
Give Technical Term:
The type of lens used to correct myopia is
What type of lens is used to correct Hypermetropia?
The diagram given below represents the cross-section of the human eye:
(i) Name the parts labeled 1—12.
(ii) What is the function of the part marked ‘10’?
(iii) What would happen if part ‘5’ is damaged or cut?
Choose the Odd One Out:
In Myopia the human eye _______.
Nearsightedness: elongated eyeball : : farsightedness: _______
Nearsightedness : concave lens : : farsightedness : _______
Differentiate the eye defects: Myopia and Hypermetropia
Correlate the given sequence:
Hypermetropia : Convex lens : ______ : Concave lens
Observe the figure and answer the following questions:
- Name the defect of vision represented in the above figure.
- State the reasons for this defect.
- How is it corrected?
- Draw the diagram to show the correction of this defect.
A teacher drew the diagram of the heart on the blackboard and told the students to copy it in their notebooks. Mahesh couldn't see the diagram clearly as it appeared blurred to him.
- Name the defect of the eye Mahesh is suffering from.
- Where is the image formed in this defect?
- Mahesh consults an eye doctor and is prescribed suitable lenses to correct the defect. Which type of lens do his spectacles have?
