A concave lens is used to form an image of a real object. The maximum distance of the image from the optical centre is

A concave lens, also known as a diverging lens, always forms a virtual, erect, and diminished image of the object. This image is formed on the same side as the object. The maximum distance of the image from the optical center of the lens would be at the focus of the lens.

Here are the steps to understand this:

1. When parallel rays of light pass through a concave lens, the refracted rays diverge from a single point on the principal axis. This point is known as the principal focus of the lens.

2. The distance between the optical center of the lens and the principal focus is called the focal length.

3. For a concave lens, the image is always formed between the object and the optical center of the lens.

4. Therefore, the maximum distance of the image from the optical center of the lens would be equal to the focal length of the lens.

5. However, the exact position of the image can vary depending on the position of the object. If the object is moved closer to the lens, the image will move closer to the optical center. Conversely, if the object is moved further away, the image will move towards the focus, but it will never surpass the focal point.

6. Therefore, the maximum distance of the image from the optical center of the lens is equal to the focal length of the lens.