The ratio of the height of the image to the height of the object is called the linear magnification. It is denoted by the letter m. While deriving the mirror formula it has been proved that D ACB and D A1CB1 are similar and so also D FB1A1 and D FED are similar.
Where h1 is the height of the image and ho is the height of the object
We know that
For a real image u and v are negative and the magnification is negative. Negative magnification means the image is inverted. On the other hand for a virtual image u is negative and v is positive and hence the magnification is positive, i.e., the image is erect.
