Mohan obtained a sharp inverted image of a distant tree on the screen placed behind the lens. He then moved the screen and tried to look through the lens in the direction of the object. He would see: (1) a blurred image on the wall of the laboratory. (2) an erect image of the tree on the lens. (3) no image as the screen has been removed (4) an inverted image of the tree at the focus of the lens.



The lens used is a biconvex lens! OK coming to question a biconvex lens forms a real and sharp image at focus of an object at infinity. Since image is real, when screen is removed it can not be seen anymore.