When would you observe a virtual image in optical devices?

A virtual image is formed when light rays diverge, making it appear as though they are emanating from a specific point rather than converging at that point. In practical terms, this occurs with certain optical devices like concave mirrors or convex lenses when the object is located within the focal length. These configurations do not allow the light rays to physically converge to form a real image; instead, the brain interprets the diverging rays as coming from a location behind the mirror or lens, thus producing a virtual image.

In contrast, the other scenarios described suggest conditions under which a real image might be observed or where light does not create a virtual image. Recognizing this concept is essential for understanding how different optical devices manipulate light to create either real or virtual images.