Question

If lower half of the body of a lens is covered with black paper, the image produced by the lens will what will be the effect on intensity?

Answer 1

A complete image will be formed, but its intensity (brightness) will decrease.

Answer 2

• Image Formation: A complete image will still be formed. This is because every point on the object sends light rays in all directions. Even if the lower half of the lens is covered, light rays from all parts of the object (top, middle, bottom) will still pass through the uncovered upper half of the lens and contribute to forming the complete image. The lens essentially acts as a smaller lens.

• Intensity: The intensity (brightness) of the image will decrease. When half of the lens is covered, the effective area available to collect light from the object is reduced by half. This means fewer light rays from the object pass through the lens to form the image. Consequently, less light energy reaches the image plane, making the image dimmer.