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प्रश्न
A person with a myopic eye cannot see objects beyond 1.2 m distinctly. What should be the type of the corrective lens used to restore proper vision?
उत्तर १
A person with a myopic eye should use a concave lens of focal length 1.2 m so as to restore proper vision.
उत्तर २
The person is able to see nearby objects clearly, but he is unable to see objects beyond 1.2 m. This happens because the image of an object beyond 1.2 m is formed in front of the retina and not at the retina, as shown in the given figure.
To correct this defect of vision, he must use a concave lens. The concave lens will bring the image back to the retina as shown in the given figure.
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संबंधित प्रश्न
Explain two possible reasons of myopia. How can it be corrected? Explain with a suitable diagram.
the biological/technical terms for the lens of eye losing flexibility resulting in a kind of long-sightedness in middle aged people.
Which defect of vision can be rectified:
by using a concave lens?
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.
From which defect of the eye is he suffering?
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.
A young man has to hold a book at arm's length to be able to read it clearly. The defect of vision is:
(a) astigmatism
(b) myopia
(c) presbyopia
(d) hypermetropia
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
Name the following:
The eye defect caused due to shortening of the eye ball from front to back.
Describe the mechanism of focusing the image of a distant object in your eye when you raise your head after reading a book.
List two causes of presbyopia. Draw labelled diagram of a lens used for the correction of this defect of vision.
Given below is a diagram depicting a defect of the human eye? Study the same and answer the question that follow:
Name the parts labeled 1 to 4.
What type of lens is used to correct Hypermetropia?
Mention, if the following statement is True or False
Hypermetropia is a defect of the eye caused due to the eyeball elongation
A person cannot see distinctly objects kept beyond 2 m. This defect can be corrected by using a lens of power:
Assertion: Concave mirrors are used as reflectors in torches, vehicle head lights and in search lights.
Reason: When an object is placed beyond the center of curvature of a concave mirror, the image formed is real and inverted.
