68th BPSC Prelims (2023), question 106

🔬 Science & Technology

106. Large number of thin strips of black paint are made on the surface of a convex lens of focal length 20 cm to catch the image of a white horse. The image will be

     1. a zebra of black stripes
     2. a horse of black stripes
     3. a horse of less brightness
     4. More than one of the above
     5. None of the above
     Show answer

     Answer: C — a horse of less brightness

     Painted strips block some light rays but the lens still forms a complete (if dimmer) image, since every point of the object sends rays through the whole unblocked lens area.