The image formed by a convex lens depends on the position of the object in front of the lens .When the object is placed anywhere between focus and infinity, the image formed by convex lens is real and inverted. The image is not obtained on the screen when the object is placed between focus and the lens. The distance between the optical center O of the convex lens and the focus point F1 or F is its focal length. 6 A student did an experiment with a convex lens. He put an object at different distances from the lens. In each case he measured the distance of the image from the lens. The results were recorded in the following table. Unfortunately, his results are written in the wrong order. (a) Arrange the image distance in the correct order (in cm). (b) Which of the object distances gives the biggest image? Give a reason. (c) Find the focal length of this lens. (d) What is the minimum distance between an object and its real image formed by a convex lens? Where should an object be placed to get a virtual image by convex lens?