Object Distance (p):
The object distance (p) is the distance between the object and the lens or mirror. It is measured along the principal axis from the object to the optical center of the lens or mirror.

Image Distance (q):
The image distance (q) is the distance between the image and the lens or mirror. It is measured along the principal axis from the image to the optical center of the lens or mirror.

Radius of Curvature (r):
The radius of curvature (r) is the distance between the center of curvature of a lens or mirror and its vertex. It is a measure of how much the lens or mirror curves.
Understanding the Relationship:
The object distance (p), image distance (q), and radius of curvature (r) are related through the lens or mirror formula. For a concave mirror or a convex lens, the formula is:
1/f = 1/p + 1/q
Where f is the focal length of the mirror or lens. The focal length is related to the radius of curvature through the formula:
f = r/2
Therefore, the object distance, image distance, and radius of curvature are all interconnected through these formulas. By knowing any two of these parameters, we can calculate the third one using the lens or mirror formula. This relationship is crucial in understanding the behavior of light rays as they pass through lenses and mirrors.

Incomplete question ^_^