In an experiment to measure the focal length ( f ) of a convex lens, the magnitude of object distance (x) and the image distance (y) are measured…

In an experiment to measure the focal length ( $\displaystyle f$ ) of a convex lens, the magnitude of object distance $\displaystyle (x)$ and the image distance $\displaystyle (y)$ are measured with reference to the focal point of the lens. The $\displaystyle y$ - $\displaystyle x$ plot is shown in figure.The focal length of the lens is $\displaystyle \_\_\_\_$ cm.