For a converging lens, if the object is placed between 2F1 and F1 the image will be formed.
Between F2 and 2F2
Draw the ray diagram. It will be beyond 2F2
If an object is placed between F1(first focus) and the optical centre of a convex lens, then the image formed will be
A diverging lens, focal length f1=20 cm is separated by 5 cm from a converging mirror, focal length f2=10 cm. Where should an object be placed from the lens so that a real image is formed at the object itself ?