A convex lens is making full image of an object. 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
Light from every point of the object passes through every part of the lens, and each part brings it to the same image point. The uncovered half therefore still forms the complete image, but only about half as much light reaches it, so the image is dimmer.
Why the other options are incorrect
Option (1) the image is not seen — Incorrect. The uncovered half still refracts light from every point of the object, so an image is formed.
Option (2) half image of the intensity, same as earlier, is seen. — Incorrect. The image is complete, not half, and it is dimmer, not equally bright.
Option (3) half image of half intensity is seen — Incorrect. Covering part of the lens does not cut the image; it only reduces its brightness.
Note: A similar question was also asked in CUET (UG) 2026 on 24-05-2026 (Slot 2).