A rod of length 10 cm lies along the principal axis of a concave mirror of focal length 10 cm in such a way that the end closer to the pole is 20 cm away from it. Find the length of the image.

Explanation

To solve the problem of finding the length of the image of a rod placed in front of a concave mirror, we can follow these steps:

### Step 1: Understand the Setup
We have a concave mirror with a focal length (f) of 10 cm. A rod of length 10 cm is placed along the principal axis of the mirror. The end of the rod closer to the mirror (point B) is 20 cm away from the pole of the mirror.

### Step 2: Identify the Positions of the Rod
Let’s denote the two ends of the rod:
- Point B (the closer end) is at a distance of 20 cm from the mirror.
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