Question

what is the formula of lens ​

Answer 1

1/v - 1/u = 1/f

This is the formula for lens

Magnification formula = height of image/height of object

Answer 2

Answer:

The lens equation expresses the quantitative relationship between the object distance (do), the image distance (di), and the focal length (f). ... The magnification equation relates the ratio of the image distance and object distance to the ratio of the image height (hi) and object height (ho).

According to the convex lens equation, 1/f = 1/v + 1/u. It relates the focal length of a lens with the distance of an object placed in front of it and the image formed of that object.