What is meant by magnification ? write it's expression. what is its sign for the (a) real (b) virtual, image?

Hey mate !

▪Magnification:-

☆Magnification produced by a spherical mirror or lens can be defined as the ratio of the height of the image to that of the object.

☆If we take h as the height of the object and h' as the height of the image, then the Magnification produced by the mirror or lens will be:-

Magnification, m = h'/h

☆The sign of the Magnification for real image is taken to be as (-)ve and it is taken as (+)ve for virtual images.

Hope it helps !