Final answer:
To form a virtual upright image at a distance of 12 cm from a converging lens with a focal length of 6 cm, the object must be placed 4 cm away from the lens.
Step-by-step explanation:
To determine the object distance, we can use the lens formula: 1/f = 1/do + 1/di, where f is the focal length of the lens, do is the object distance, and di is the image distance. In this case, the focal length is 6 cm and the image distance is 12 cm. Substituting these values into the formula, we get: 1/6 = 1/do + 1/12. Simplifying this equation, we find that do = 4 cm. Therefore, the object must be placed 4 cm away from the converging lens to form a virtual upright image at a distance of 12 cm from the lens.