If the lower half of a concave mirror's reflecting surface is covered with an opaque (non-reflecting) material. Then,
Answer & explanation
Correct answer: option 4
The correct answer is Option (4) → the image will be that of the whole object with half the intensity
Rays from every point of the object fall on the whole reflecting surface, and each part of the mirror sends them to the same image point. Covering the lower half does not stop rays from any part of the object reaching the image; it only cuts off half of the reflecting area.
So the image is still complete, but only half as much light forms it, and it is less bright (half the intensity).
Why the other options are incorrect
Option (1) the image will show only lower half of the object. — Incorrect. Each part of the mirror forms the whole image, so no part of the object is missing from the image.
Option (2) the image will show only upper half of the object. — Incorrect. For the same reason the image is not cut to the upper half of the object either.
Option (3) no image will be visible — Incorrect. The uncovered half still reflects rays from every point of the object, so an image is formed.
NCERT (2026-27):
The Mirror Equation – …
