For a distant object, a converging lens forms an image at which location?

• A. At infinity
• B. At the focal plane on the opposite side
• C. At the focal point on the same side
• D. At the center of curvature

Answer: (B)

When the object is very far away, the light entering the lens is essentially made of parallel rays. A converging lens bends those parallel rays so they meet at a single point on the opposite side of the lens, located a distance equal to the lens’s focal length from the lens. That point lies in the focal plane on the far side, so the image forms there. The other locations don’t fit because parallel rays don’t continue to stay parallel after the lens; they must converge at the focal point on the far side, not on the near side, not at the center of curvature, and not at infinity.