The correct answer is option 3: 0-5.
A concave lens is a lens that is thinner in the middle and thicker at the edges. It causes light rays to diverge or spread out. The focal length of a lens is the distance at which parallel rays of light converge or diverge after passing through the lens. In this case, the focal length of the concave lens is 10 cm.
When an object is placed at a distance greater than the focal length of a concave lens, an image is formed on the same side as the object. The image formed is virtual, upright, and diminished in size.
In this scenario, the image is formed at a distance of 5 cm from the lens. The magnification produced by a lens is the ratio of the height of the image to the height of the object. In this case, since the image is formed on the same side as the object, the height of the image is negative.
Therefore, the magnification in this scenario is -0.5, which can be written as 0-5. This means that the image is half the size of the object and inverted.