Question

An object is placed at a certain distance from the optic centre of a convex lens of of focal length 20 cm. A real image is formed at 60 cm from the optic centre of the lens.The object distance “u” is

Answer 1

Therefore the object must be placed at a distance of 72 cm from the focal length of the lens. And the magnification of the image formed will be inverted this could be seen by the negative sign obtained. And this sign indicates the position in respect to the coordinate where the focal length of the lens is placed.