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How will the image formed by a convex lens be affected, if the upper half of the lens is wrapped with a black paper?
How will the image formed by a convex lens be affected, if the upper half of the lens is wrapped with a black paper?
Updated On: Jan 13, 2026
- The size of the image formed will be one-half of the size of the image due to complete lens.
- The image of upper half of the object will not be formed.
- The brightness of the image will reduce.
- The lower half of the inverted image will not be formed.
Show Solution
The Correct Option is C
Solution and Explanation
Step 1: Understand convex lens image formation
A convex lens refracts light rays to converge and form an image. All parts of the lens contribute to the complete image formation.
Step 2: Impact of obscuring part of the lens
Covering the upper half of a convex lens with black paper restricts light passage to the lower half.
- The lens continues to refract light and form an image as the lower portion can still focus rays onto the image plane.
- Consequently, with reduced light entry, the image intensity diminishes.
Step 3: Summary
The resultant image will remain complete (not halved), but its brightness will be reduced compared to the original.
Final Answer:
The image's brightness will decrease.
A convex lens refracts light rays to converge and form an image. All parts of the lens contribute to the complete image formation.
Step 2: Impact of obscuring part of the lens
Covering the upper half of a convex lens with black paper restricts light passage to the lower half.
- The lens continues to refract light and form an image as the lower portion can still focus rays onto the image plane.
- Consequently, with reduced light entry, the image intensity diminishes.
Step 3: Summary
The resultant image will remain complete (not halved), but its brightness will be reduced compared to the original.
Final Answer:
The image's brightness will decrease.
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