Choose the position of object, kept before a lens to form image of same size as that of the object.
concave lens, at 2F1
convex lens, at 2F1
concave lens, at F1
convex lens, at F1
Draw well labelled ray diagrams for image formation by convex lens when
(1) Object is at 2F1
(2) Object between F1 and 2F1
(3) Object between focus F1 and optical centre O.