What focal length should the reading spectacles have for a person whose near point is `50 cm` ?

Explanation

To find the focal length of the reading spectacles for a person whose near point is 50 cm, we can follow these steps:

### Step 1: Understand the Problem
The near point of a person is the closest distance at which they can see objects clearly. In this case, the near point is 50 cm. The person wants to read a book placed at a distance of 25 cm.

### Step 2: Identify the Object and Image Distances
- The object distance (u) is the distance of the book from the person, which is 25 cm. Since we are using the convention where distances measured against the direction of incident light are negative, we have:
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