A concave lens has focal length of 15 cm. At what distance should an object from the lens be placed so that it forms an image at 10 cm from the lens ? Also, find the magnification of the lens.

Explanation

To solve the problem step by step, we will use the lens formula and the magnification formula for a concave lens.

### Step 1: Identify the given values
- Focal length of the concave lens (f) = -15 cm (negative because it is a concave lens)
- Image distance (v) = -10 cm (negative because the image is virtual)

### Step 2: Use the lens formula
The lens formula is given by:
...