The image image of an object placed at a distance of 30 cm on the principal axis of a concave mirror from its pole is formed on the object itself. Find (a) the focal length and (b) linear magnification of mirror:

Explanation

To solve the problem, we will follow these steps:

### Step 1: Understand the Given Information
We have a concave mirror with an object placed at a distance of 30 cm from its pole. The image is formed at the same location as the object, which means the image distance (v) is also -30 cm (the negative sign indicates that the image is formed on the same side as the object).

### Step 2: Identify the Relationship Between Object Distance, Image Distance, and Focal Length
We know that for mirrors, the mirror formula is given by:
\[ \frac{1}{f} = \frac{1}{v} + \frac{1}{u} \]
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