An object is placed before a convex lens and its real image is obtained. Now if half of the surface is covered with paper. The result will be:
Answer & explanation
Correct answer: option 4
The correct answer is Option (4) → Full image will be formed with less brightness
Rays from every point of the object fall on every part of the lens, and each part of the lens brings them to the same image point. So the uncovered half alone still forms the complete image at the same place. Only half as much light reaches the image, so it is less bright.
Option (1) No image will be formed — Incorrect. The uncovered half still refracts light from every point of the object, so an image is formed.
Option (2) Half image will be formed — Incorrect. Each part of the lens receives light from the whole object, so the whole image forms, not half of it.
Option (3) Image will be same as before — Incorrect. The position and size are the same, but less light reaches the image, so it is dimmer than before.
Option (4) Full image will be formed with less brightness — Correct. The image is complete, at the same place, but less bright because half the light is blocked.