Question
We cannot clearly see an object kept at a distance less than 25 cm from eye.###If we bring an object closer than 25 cm from the eyes, why can we not see it clearly even though it subtends a bigger angle at the eye?

Answer

(i) The minimum distance at which an object is placed from the normal eye so that it can be seen clearly without giving any strain on the eye is called the distance of the distinct vision.
(ii) This distance is 25 cm for a normal human eye.
(iii) If the object is placed at a distance less than 25 cm, ciliary muscles is unable to adjust the lens there is a strain on the eye and it cannot be seen clearly.
(iv) Hence an object should be placed at 25 cm or more to have a clear and sharp image of it on the retina.

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