The correct answer is m = -1. Explanation & Key Takeaways: • When an object is placed at a distance of 2f from a convex lens, the image is formed at a distance of 2f on the other side of the lens. • The image formed is real, inverted, and of the same size as the object. • Magnification (m) = Height of Image / Height of Object = -1 (negative sign indicates inversion). • This scenario is a standard case in lens formulas and ray diagrams of convex lenses. • Thus, magnification 'm' = -1 for object placed at 2f in convex lens. Related Concepts: • Convex Lens (Converging Lens) • A convex lens is thicker at the center and converges parallel rays of light to a point called the focus. • It forms real and inverted images for object distances greater than focal length (f), and virtual, erect images when the object is within f. • Magnification (m) • Magnification = v/u or Height of Image / Height of Object. • Positive magnification indicates an erect image, negative indicates an inverted image. • Lens Formula • 1/f = 1/v - 1/u where f = focal length, v = image distance, u = object distance. • All distances are measured from the optical center of the lens. • Applications of Convex Lens • Used in magnifying glasses, microscopes, cameras, and human eye correction.