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प्रश्न
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.
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उत्तर
Myopia (short-sightedness) is a defect of vision that can be corrected by using diverging or concave lenses. The following ray diagram clearly shows the correction of myopia by using a diverging lens.
A person with myopia does not see distant objects clearly but has normal near vision. Fig. (a) shows the far point of the myopic eye, and fig. (b) shows the parallel light rays from a distant object forming an image at a point in front of the retina. To correct this defect, a concave lens is used, because of which, in fig. (c), we observe the rays being diverged first so that they form a clear image on the retina.
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संबंधित प्रश्न
What is myopia?
A student is unable to see clearly the words written on the blackboard placed at a distance of approximately 4 m from him. Name the defect of vision the boy is suffering from. Explain the method of correcting this defect.
Draw ray diagram for the:-
(i) defect of vision and also
(ii) for its correction.
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.
What is the scientific name of
long-sightedness?
A student sitting in the last row of the class-room is not able to read clearly the writing on the blackboard.
Name the type of defect he is suffering from.
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 converging lens. Show clearly by a ray diagram how the lens corrects the defect.
Name the following:
The photosensitive pigment present in the rods of the retina.
Explain the terms ‘adaptation’ and ‘accommodation’ with reference to the eye.
You do not enjoy watching a movie from a very short distance from the screen in a cinema hall. Why?
Observer the following diagram and answer the questions.
a) Which eye defect is shown in this diagram?
b) What are the possible reasons for this eye defect?
c) How this defect is corrected, write it in brief?
Write whether the following is true or false:
A convex lens is used for correcting myopia.
Choose the correct answer :
Presbyopia is a disease of _____________
Due to elongation of _______ and increase in curvature of the eye lens, a person cannot see distant objects clearly.
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.
Myopia may arise due to ____________.
Correlate the given sequence:
Hypermetropia : Convex lens : ______ : Concave lens
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?
