An object is placed 15cm from a mirror and an image is captured on the screen with magnification 2. Calculate the focal length of the mirror and determing if it is concave or convex.

Explanation

To solve the problem step by step, we will use the mirror formula and the magnification formula.

### Step 1: Identify the Given Information
- Object distance (u) = -15 cm (negative because it is a concave mirror)
- Magnification (m) = 2

### Step 2: Determine the Image Distance (v)
The magnification (m) is given by the formula:
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