The focal length of a convex lens is f . An object is placed at a distance x from its first focal point. The ratio of the size of the real image to that of the object is

Step-by-step solution

Given that, focal length of convex lens =f Distance of object from lst focus point =x Now, object distance, u=-(f+x) We know that, ratio of size of real image to that of object = magnification which is given by m= v u = f f+u m= f f-(f+x) =- f x Taking magnitude only, |m|= f x .