$(i)$ To construct a ray diagram, we use two light rays chosen such that their directions after reflection from the mirror are easily determined. List these two rays and state their paths after reflection. Use these two rays to locate the image of an object placed between infinity and the centre of curvature of a concave mirror.
(ii) Draw a ray diagram to show the formation of an image of an object placed between the pole and the principal focus of a concave mirror. How will the nature and size of the image change if the mirror is replaced by a converging lens of the same focal length?

(N/A) $(i)$ Two rays commonly used are:
$1$. A ray parallel to the principal axis: After reflection, it passes through the principal focus $F$.
$2$. A ray passing through the centre of curvature $C$: After reflection, it reflects back along the same path.
For an object placed between infinity and $C$, the image is formed between $F$ and $C$, and it is real, inverted, and diminished.
(ii) When an object is placed between the pole $P$ and the principal focus $F$ of a concave mirror, a virtual, erect, and magnified image is formed behind the mirror. If the mirror is replaced by a converging lens of the same focal length, the object (placed between $O$ and $F_1$) will form a virtual, erect, and magnified image on the same side as the object, but the image will be further away from the lens compared to the mirror case.