A convex lens of focal length `f` is placed somewhere in between an object and a screen. The distance between the object and the screen is `x`. If the numerical value of the magnification produced by the lens is `m`, then the focal lnegth oof the lens is .

Options

A. `(mx)/((m+1)^(2))`
B. `(mx)/((m-1)^(2))`
C. `((m+1)^(2))/m`x
D. `((m-1)^(2))/m`x

Answer

A

Explanation

(d) Here, x=u+v
Magnification, `m=f/(f-u)=(f-v)/f\