If 'x' is the distance of far point of defective eye, 'f' is the focal length of lens used for correcting this defect. Derive an expression for 'f'

Explanation

To derive the expression for the focal length \( f \) of the lens used to correct the defective eye, we can follow these steps:

### Step-by-Step Solution:

1. **Understanding the Far Point**:
- The far point of a defective eye is the furthest distance at which the eye can see clearly. Let this distance be denoted as \( x \).

2. **Defining Object and Image Distances**:
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