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Question
A student sitting in the last row of the class-room is not able to read clearly the writing on the blackboard.
How can this defect by corrected?
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Solution
To correct his defect, he should use concave lenses in his spectacles.
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RELATED QUESTIONS
What is the far point and near point of the human eye with normal vision?
Name the defect of vision in a person:
whose far point is less than infinity
Where is the near point of a person suffering from hypermetropia (or long-sightedness)?
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?
A man can read the number of a distant but clearly but he finds difficulty in reading a book.
What type of spectacle lens should he use to correct the defect?
Explain with the help of labelled ray diagram, the defect of vision called myopia and how it is corrected by a lens.
Name the following:
The photosensitive pigment present in the rods of the retina.
Write whether the following is true or false:
A convex lens is used for correcting myopia.
Give Reason:
Older people require glasses to read and write.
Differentiate between:
Short-sightedness and Long-sightedness.
Explain the Term: Presbyopia
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.
Differentiate the eye defects: Myopia and Hypermetropia
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
A person is unable to see clearly a poster fixed on a distant wall. He however sees it clearly when standing at a distance of about 2 m from the wall.
- Draw ray diagram to show the formation of image by his eye lens when he is far away from the wall.
- List two possible reasons of this defect of vision.
- Draw ray diagram to show the correction of this defect using appropriate lens.
Observe the following diagram and answer questions following it:
- Identify the defect of vision shown.
- List its two causes.
- Name the type of lens used for the correction of this defect.
Name the following:
Two kinds of accomodations.
