Question

why magnification is taken negative for real images and for positive for virtual images?

Answer 1

The question is a very common one.

Magnification is the ratio between the height of the object and the height of the image.

In the case of a real image, the height of the object carries a positive sign while the height of the image carries a negative one.

Hence the magnification is negative.

In case of a virtual image, the height of the image, as well as the height of the object, carries a positive sign.

Therefore, the magnification is positive in this case.

Answer 2

hola

Distances measured on the other side are negative. f, the focal length, is positive for a concave mirror, andnegative for a convex mirror. When theimage distance is positive, the imageis on the same side of the mirror as the object, and it is real and inverted.