When object AB is placed between pole P and focus F then the image is formed behind the mirror which is virtual and erect (same side up as the object).

The image is larger in size than the object i.e. magnified.

Light ray AD which is parallel to axis gets reflected at D and passes through focus F and ray AE passes through centre of curvature after striking the concave mirror. Both reflected rays EC and DF are diverging. When these reflected rays are produced backwards, they intersect at A’ behind the concave mirror. Then we draw A’B’ perpendicular to axis thus A’B’ is the virtual image of the object.