A thin stick of length f/5 placed along the principal axis of a concave mirror of focal length f such that its image is real and elongated just touch the stick. What is the magnification?

Explanation

To solve the problem, we need to find the magnification of the image formed by a concave mirror when a thin stick of length \( \frac{f}{5} \) is placed along the principal axis. The stick's image is real and elongated, just touching the stick.

### Step-by-Step Solution:

1. **Understand the Setup**:
- We have a concave mirror with a focal length \( f \).
- A thin stick of length \( \frac{f}{5} \) is placed along the principal axis.
- The image formed is real and elongated, touching the stick.
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