What is long-sightedness? The near point of a long-sighted person is at $100 c m$ from his eyes. What would be the power of the lens to be used by him in order to read a book placed at $25 c m$ from his eyes?

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Long-sightedness
If anyone find it difficult to focus on things close up, or if objects near appear blurry, it could be a sign that the person suffers from long sightedness. Distance vision in long-sighted people generally remains clear.
Long sightedness makes reading difficult, particularly if the type is small.
The diagram shows the picture of long or farsightedness and its remedy using converging lens.
Numerical:-
The image and the actual object are on the same side, so the image is considered negative. The real object is at $25 c m$ away from the front of the lens $u = - 25 c m$ , and we want to produce an image that appears to be $100 c m$ away from the lens $v = 100 c m$ . Plug everything into the lens' formula:
$P o w e r = \frac{1}{f} = \frac{1}{v} - \frac{1}{u}$
$P o w e r = \frac{1}{0.25 (m e t e r)} - \frac{1}{1 (m e t e r)}$
Hence, $Power=3 diopter or 3D$

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What is long-sightedness? The near point of a long-sighted person is at 100 cm from his eyes. What would be the power of the lens to be used by him in order to read a book placed at 25 cm from his eyes?

What is long-sightedness? The near point of a long-sighted person is at $100 c m$ from his eyes. What would be the power of the lens to be used by him in order to read a book placed at $25 c m$ from his eyes?