A point object O is placed on the principal axis of a convex lens of focal length f= 20 cm at a distance of 40 cm to the left of it. The diameter of the lens is 10 cm. An eye is placed 60 cm to right of the lens and a distance h below the principal axis. The maximum value of h to see the image is

As, f=20, so 2f=R=40. So, image will be formed at 40 cm of opposite side. Now, to see this, the height must accomplish with the angle formed. . So, . So, h=2.5.