Which one is the correct relation among f,u and v in lens?

The correct answer is C = \(\frac1u+\frac1v=\frac1f\)

f=u−vu×v.The equation connecting the distance between mirror and object (u), distance between mirror and image (v), and the focal length of the mirror (f) is called mirror formula. From u-v graph : We can measure the focal length of the given concave mirror graphically by plotting graph between u and v.V is the image, image distance, so this is image distance, and that's something we don't know in this problem. And u is the object distance, these are the letters that we usually use for mirrors, object distance.

And for image distance, V in lens it is taken as positive in Convex lens since image is formed on +X side. It is taken as negative in Concave lens since image is formed in -X side of the Cartesian. In Concave mirror V is taken as positive and negative for convex mirror.The distance between the object and the pole of the mirror is called the object distance(u). The distance between the image and the pole of the mirror is called Image distance(v).

Concave mirrors can form real images. Convex and plane mirrors always form virtual images.A spherical mirror is simply a piece cut out of a reflective sphere. Its center of curvature, C, is the center of the sphere it was cut from. R, the mirror's radius of curvature is the radius of the sphere.The magnification of a concave mirror is given by the ratio of the height of the image to the height of the object. ... Hence, if the image is inverted and real the magnification will be negative.