Observe the following diagram showing an image formation in an eye : (a) Identify the defect of vision shown in the figure. (b) List its two causes and suggest a suitable corrective lens to overcome this defect.
Observe the following diagram showing an image formation in an eye : (a) Identify the defect of vision shown in the figure. (b) List its two causes and suggest a suitable corrective lens to overcome this defect.
The defect of vision shown in the figure is myopia or near-sightedness. The two causes of myopia are (i) excessive curvature of the eye lens, and (ii) elongation of the eyeball. A suitable corrective lens to overcome this defect is a concave lens of appropriate power.
Marking Scheme
- 1Myopia or near-sightedness
- 2Excessive curvature of the eye lens
- 3Elongation of the eyeball
- 4Concave lens of appropriate power
Hint
The diagram shows an image formation in an eye where the image is formed in front of the retina, indicating myopia.
Quick Oral Answer
Myopia or near-sightedness is a defect of vision where a person can see nearby objects clearly but cannot see distant objects distinctly. The diagram shows an image formation in an eye where the image is formed in front of the retina, indicating myopia. The two causes of myopia are (i) excessive curvature of the eye lens, and (ii) elongation of the eyeball. A suitable corrective lens to overcome this defect is a concave lens of appropriate power.
Analysis & Explanation
Myopia or near-sightedness is a defect of vision where a person can see nearby objects clearly but cannot see distant objects distinctly. The diagram shows an image formation in an eye where the image is formed in front of the retina, indicating myopia. The two causes of myopia are (i) excessive curvature of the eye lens, and (ii) elongation of the eyeball. A suitable corrective lens to overcome this defect is a concave lens of appropriate power.
Common Mistakes
- 1Hypermetropia or far-sightedness
- 2Presbyopia
Interesting Facts
Myopia is a common defect of vision that affects many people worldwide.
The causes of myopia are not fully understood, but it is thought to be related to genetics and environmental factors.
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Frequently Asked Questions
How many marks does this question carry in CBSE Class 10 Science 2023?
This question carries 2 marks in the CBSE Class 10 Science 2023 examination.
Which chapter does this question come from in Science?
This question is from the chapter "The Human Eye and the Colourful World" in the CBSE Class 10 Science syllabus.
What topic does this question cover in Science?
This question covers the topic "Defects of Vision" from CBSE Class 10 Science.
What type of question is this in the CBSE Class 10 Science 2023 paper?
This is a Very Short Answer question from Section B in the CBSE Class 10 Science 2023 paper.