An object of size `7.0 cm` is placed at `27 cm` in front of a concave mirror of focal length `18 cm`. At what distance from the mirror, should a screen be placed, so that a sharp focussed image can be obtained ? Find the size and nature of the image ?

Explanation

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

### Step 1: Identify the given values
- Object size (height, H1) = 7.0 cm (positive since it's above the principal axis)
- Object distance (U) = -27 cm (negative because the object is in front of the mirror)
- Focal length (F) = -18 cm (negative for a concave mirror)

### Step 2: Use the mirror formula
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