Advertisements
Advertisements
प्रश्न
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.
उत्तर
Hypermetropia (long-sightedness) is a defect of vision that can be corrected by using converging lenses. The following ray diagram shows the correction of hypermetropia using a convex lens.
A person with hypermetropia cannot see nearby objects clearly but can see distant objects normally. Fig. (a) shows the near point of the hypermetropic eye, and fig. (b) shows the rays of light from a nearby object forming a blurred image, as the image is formed at a point behind the retina. To correct this defect, convex lenses are used in spectacles, because of which, as illustrated in fig. (c), the rays of light from the nearby object are converged to form a clear and sharp image of the object on the retina.
APPEARS IN
संबंधित प्रश्न
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?
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
What is meant by optical illusion? Give one example.
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?
Select the odd one in the following series:
Endolymph, Tympanic membrane, Semi-circular canal, Blind spot.
Nearsightedness: elongated eyeball : : farsightedness: _______
Myopia and hypermetropia can be corrected by:
Draw ray diagram showing myopic eye.
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?
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.
