Which type of lens can produce a real image?

• A. Concave lens
• B. Convex lens
• C. Planar lens
• D. Spherical lens

Answer: (B)

A real image is formed when light rays actually converge to a point after passing through a lens, so that the image can be projected onto a screen. A convex lens is a converging lens, which bends incoming light toward a common point on the opposite side. If the object is placed outside the focal length, the refracted rays cross and form a real, inverted image on that side of the lens. You can project this image onto a screen. If the object is at the focal length, the rays emerge parallel and no finite image forms; if the object is closer than the focal length, the lens produces a virtual, upright image instead.

In contrast, a concave lens diverges light and typically only yields virtual images that can’t be projected. A planar lens doesn’t focus light to form a real image in the usual sense, and a spherical lens is not a single type by itself—its real-imaging behavior depends on whether its surfaces are arranged as convex (converging) or concave (diverging).