Question

Why is the normal eye not able to see clearly the objects
closed at 25cm ?​

Answer 1

Answer:

A normal eye is unable to clearly see the objects placed closer than 25 cm because the ciliary muscles of eyes are unable to contract beyond a certain limit.

Answer 2

⏭ Your Answers:

This is a nice question to answer!

✳ With change in object distance, the eye also changes the focal length of the eye lens such that it can get a sharp image formed on the retina( The screen on which image is formed). This process is known as Accommodation.

Although this power of our eye is amazing but still it having many limitations. The focal length cannot adjust enough to form sharp image beyond a limit.

• The farthest point to which the eye can see properly is called far point. For our eye, the far point is infinity. The eye lens in its maximum focal length at an object at the far point.
• But, When it is brought closer, the culinary muscles contract. This increases the thickness and decreases the focal length of the eye lens. After a certain distance, it can't contract further. This is the near point.

✏ The near point of eye varies with person to person, age to age. I think, the average or standard value of least distance of distinct vision for the normal human eye, it is taken as 25 centimetres$.$

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