To construct ray diagram we use two light rays which are so chosen that it is easy to know their directions after reflection from the mirror. List these two rays and state the path of these rays after reflection. Use these rays to locate the image of an object placed between centre of curvature and focus of a concave mirror.

To construct a ray diagram, we can choose any two of the following standard rays:

1. Ray parallel to the principal axis: After reflection, this ray passes through the principal focus ($F$) of a concave mirror.
2. Ray passing through the principal focus ($F$): After reflection, this ray emerges parallel to the principal axis.

Locating the image of an object placed between $C$ and $F$ of a concave mirror:

• When an object $AB$ is placed between the centre of curvature ($C$) and the principal focus ($F$), a ray parallel to the principal axis reflects and passes through $F$.
• A second ray passing through $F$ reflects and emerges parallel to the principal axis.
• These two reflected rays intersect at a point $A'$ beyond the centre of curvature ($C$).
• Therefore, the image $A'B'$ is formed beyond $C$. It is real, inverted, and enlarged (magnified).