### Theory:

We shall now find the image's position, size, and nature by drawing the ray diagram for a small linear object placed on the principal axis of a concave mirror at different positions.

Case-I: When the object is placed at infinity, the light rays reaching the concave mirror parallel each other.
Position of the Image: The image is formed at the principal focus $$F$$.
Nature of the Image: It is real, inverted and highly diminished in size.

Case-II: When the object is placed beyond the centre of curvature.

Position of the image: Between the principal focus $$F$$ and centre of curvature $$C$$.
Nature of the image: Real, inverted and smaller than an object.

Case-III: When the object is placed exactly at the centre of curvature.

Position of the image: The image is at the centre of curvature itself.
Nature of the image: It is real, inverted, and the same size as the object.

Case-IV: When the object is placed between the centre of curvature $$C$$ and principal focus $$F$$.

Position of the image: The image is beyond $$C$$.
Nature of the image: Real, inverted and magnified.

Case-V: When the object is placed at the principal focus $$F$$.
Nature of the image: No image can be captured on the screen, nor any virtual image can be seen.

Case-VI: When the object is placed between the focus $$F$$ and the pole $$P$$.
Position of the image: The image is behind the mirror.
Nature of the image: It is virtual, erect and magnified.