Now we will use these three rays to construct a ray diagram in order to locate an image as you see in the simulation. For that on a separate sheet of paper draw the optical axis and the lens plane. Use your value of the focal length to mark the left and right side focal points and label them each “F.” Now draw an arrow with its base at the optical axis which has a height, h, of 2.0 cm and is located 9.0 cm from the center of the lens (9.0 cm will be the object distance, s). This arrow represents the object.