A point object $\mathrm{O}$ is placed on the principal axis of a convex lens of focal length $f=20 \mathrm{cm}$ at a distance of $40 \mathrm{cm}$ to the left of it. The diameter of the lens is $10 \mathrm{cm}$. An eye is placed $60 \mathrm{cm}$ to the right of the lens and a distance $h$ below the principal axis. The maximum value of $h$ to see the image is. (assume paraxial approximation to be valid here)