A real image is formed by a convex lens on the screen. If half of the lens is covered by an opaque object, then
Answer & explanation
Correct answer: option 4
The correct answer is Option (4) → full image of decreased intensity is seen
Every part of a lens forms a complete image: rays from each point of the object pass through all parts of the lens and meet at the same image point. Covering half the lens only blocks half of these rays, so every image point still forms, but with fewer rays reaching it. The full image is seen with reduced intensity (about half).
Why the other options are incorrect
Option (1) half image is not seen — Incorrect. No part of the image is lost, because the uncovered half still sends rays from every object point to its image point.
Option (2) full image of same intensity is seen — Incorrect. The image is complete, but half the light is blocked, so it cannot be equally bright.
Option (3) half image of same intensity is seen — Incorrect. The image is neither halved nor equally bright.
Note: A similar question was also asked in CUET (UG) 2026 on 25-05-2026 (Slot 1).