The figure below shows an object $AB$ placed on the principal axis of a convex lens placed in air. $F_{1}$ and $F_{2}$ are the two foci of the lens. Copy the diagram.
$(i)$ Draw a ray of light starting from $B$ and passing through $O$. Show the same ray after refraction by the lens.
$(ii)$ Draw another ray from $B$ which passes through $F_{2}$ after refraction by the lens.
$(iii)$ Locate the final image formed.
$(iv)$ Is the image real or virtual?

(N/A) The object $AB$ is placed between the optical center $O$ and the principal focus $F_{1}$ of the convex lens.
$(i)$ $A$ ray of light starting from $B$ and passing through the optical center $O$ goes straight without any deviation.
$(ii)$ $A$ ray of light starting from $B$ and moving parallel to the principal axis passes through the focus $F_{2}$ after refraction by the lens.
$(iii)$ The two refracted rays appear to diverge from a point $B'$. By dropping a perpendicular from $B'$ to the principal axis,we get the point $A'$. Thus,$A'B'$ is the virtual image of the object $AB$.
$(iv)$ The image formed is virtual and erect.