Page 164 – Intext Questions & Answers
Q1. What is meant by power of accommodation of the eye?
Answer:
The power of accommodation of the eye is the ability of the eye lens to change its focal length so that it can clearly focus both near and distant objects on the retina by adjusting its curvature using ciliary muscles.
Q2. A person with a myopic eye cannot see objects beyond 1.2 m distinctly. What should be the type of corrective lens used to restore proper vision?
Answer:
A concave lens (diverging lens) should be used.
Reason:
In myopia, images of distant objects are formed in front of the retina. A concave lens diverges the incoming light rays so that the image forms on the retina, restoring clear vision.
Q3. What is the far point and near point of the human eye with normal vision?
Answer:
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Near point (least distance of distinct vision) = 25 cm
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Far point = Infinity (∞)
Meaning:
A normal human eye can see objects clearly from 25 cm to infinity.
Q4. 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?
Answer:
The child is likely suffering from Myopia (near-sightedness).
Correction:
It can be corrected by using concave (diverging) lenses, which help focus distant images clearly onto the retina.