A converging lens is used to form image on a screen. When the lower half of the lens is covered by an opaque screen then, the correct statements are:
(A) Intensity of Image will decrease.
(B) Intensity of Image will increase.
(C) Complete Image will be formed.
(D) Half the Image will disappear.
Choose the correct answer from the options given below.
Answer & explanation
Correct answer: option 3
The correct answer is Option (3) → (A) and (C) Only
Every point of the object sends rays to all parts of the lens, and the rays that pass through any part of the lens meet at the same image point. Covering half the lens only cuts down the number of rays reaching the image.
(A) Intensity of Image will decrease — Correct. Only half the light now passes through the lens, so the image is dimmer.
(B) Intensity of Image will increase — Incorrect. Blocking light cannot make the image brighter.
(C) Complete Image will be formed — Correct. The uncovered half still collects rays from every point of the object and brings them to the corresponding image points.
(D) Half the Image will disappear — Incorrect. No part of the image is lost; only its brightness changes.