Final answer:
The center of curvature of the mirror is 24 cm and the object should be placed 12 cm from the mirror.
Step-by-step explanation:
The center of curvature of a concave mirror is located at twice the focal length. In this case, the focal length is given as 12 cm, so the center of curvature would be at 2 times 12 cm, which is 24 cm.
An object of length 4 cm should be placed at a distance equal to the focal length from the concave mirror. Since the focal length is 12 cm, the object should be placed at 12 cm from the mirror.
The center of curvature of the mirror is 24 cm and the object should be placed 12 cm from the mirror.