Differentiating real and virtual images

Abstract

Plane and convex mirrors create only virtual images while concave mirrors can create both virtual and real images. A virtual image is one that cannot be obtained on a screen and can only be seen when looking directly at the optical device. The image is formed by the convergence of the rays’ extensions after reflection or refraction, not by the convergence of the rays themselves. In contrast, a real image occurs where rays do in fact converge. This image can be seen on a screen or when standing in an appropriate position in front of an optical device (as seen in figure 1(a), while an observer standing at point Y in the field of vision can see this image, observers standing outside the field of vision at points X and Z cannot). A virtual image, however, can generally be seen by all observers positioned in front of the mirror. For example, in figure 1(b), all of the observers positioned at points K, L and M can see the virtual image. From this we can conclude that a virtual image has a larger field of vision than a real image.