Copy the given figure and complete it to show the formation of the image of the object $AB$. Name the lens used in the figure.

(CONCAVE LENS) Since the incident ray of light parallel to the principal axis is diverged by the lens,the lens used is a concave lens.
To complete the ray diagram:
$1$. Draw a concave lens at the position indicated.
$2$. Extend the diverged ray backwards until it appears to pass through the focus $F_2$.
$3$. Draw a second ray from the top of the object $B$ passing through the optical center of the lens. This ray will pass undeviated.
$4$. The point where these two rays appear to intersect gives the position of the image $A'B'$.
The completed figure is as shown below.