Question

The focal length of a concave mirror is 'f'and the distance of the object to the principal focus is p then the ratio of size of the image to size of the object is ​

Answer 1

h/h` will be the ratio of the object to image

Answer 2

The distance between the pole P of the concave mirror and the focus F is the focal length of the concave mirror. Thus, the focal length of a concave mirror can be estimated by obtaining a 'Real image' of a distant object at its focus, as shown in the figure.