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प्रश्न
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?
उत्तर
Looking glasses with the concave lens are required here.
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संबंधित प्रश्न
The kind of lens required to correct Myopia
What is the other name for
hypermetropia
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?
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?
The defect of vision which cannot be corrected by using spectacles is:
(a) myopia
(b) presbyopia
(c) cataract
(d) hypermetropia
Differentiate between members of the following pair with reference to what is asked in bracket.
Myopia and hyperopia (cause of the defect)
You do not enjoy watching a movie from a very short distance from the screen in a cinema hall. Why?
A person is unable to see distinctly the objects closer than 1 m. Name the defect of vision he is suffering from. Draw ray diagrams to illustrate the cause of the defect and its correction by suitable lens.
Draw a ray diagram to show how Hypermetropia is defect can be corrected using a lens.
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?
Rewrite the following table so as to match second and third column with first column.
|
Column I
|
Column II
|
Column III
|
|
(i) Myopia
|
Old age problem
|
Bifocal lens
|
|
(ii) Presbyopia
|
Nearsightedness
|
Concave lens.
|
Name the common defects of the eye.
Nearsightedness : concave lens : : farsightedness : _______
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.
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.
When do we consider a person to be myopic or hypermetropic? Explain using diagrams how the defects associated with myopic and hypermetropic eye can be corrected?
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 | ______ | ______ |
Name the following:
Two kinds of accomodations.
