Question

How will the image formed by a convex lens be affected, if the upper half of the lens is wrapped with a black paper?

• A. The size of the image formed will be one-half of the size of the image due to complete lens.
• B. The image of upper half of the object will not be formed.
• C. The brightness of the image will reduce.
• D. The lower half of the inverted image will not be formed.

Answer 1

The Correct Option is C

Step 1: Understand how a convex lens forms an image
A convex lens bends (refracts) light rays to converge and form an image. Each part of the lens contributes to forming the complete image.

Step 2: Effect of covering part of the lens
If the upper half of the convex lens is covered with black paper, light can only pass through the lower half of the lens.
- The lens still bends light and forms an image, because the lower part can still focus rays onto the image plane.
- However, since less light enters the lens, the intensity of the image is reduced.

Step 3: Conclusion
The image formed will still be complete (not half), but it will be less bright than the original.

Final Answer:
The brightness of the image will reduce.