A far sighted person cannot focus distinctly on objects closer than Im. What is the power of lens that will permit him to read from a distance of 40cm?

Explanation

To solve the problem step by step, we need to determine the power of the lens required for a far-sighted person to read from a distance of 40 cm. Here’s how we can approach it:

### Step 1: Understand the problem
A far-sighted person has a near point of 1 meter (100 cm), meaning they cannot see objects clearly that are closer than this distance. We want to find the power of a lens that allows them to read at a distance of 40 cm (0.4 meters).

### Step 2: Identify the variables
- Near point (D) = 1 m (100 cm)
- Object distance (u) = -0.4 m (since the object is in front of the lens, we take it as negative)
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