Question

Lower half of a convex lens is made opaque. Which of the following describes the image of the object placed in front of the lens?(A) No change in image
(B) Image will show only half of the object
(C) Intensity of image gets reduced
Choose the correct answer from the options given below.

• A. (A) only
• B. (B) only
• C. (B )(C) only
• D. (C) only

Answer 1

The Correct Option is D

The question involves a convex lens with its lower half made opaque. We need to understand how this affects the image of an object positioned in front of the lens.

Let's analyze each option:

1. No change in image: For a lens, light that passes through any part contributes to the formation of the complete image. Hence, even if half the lens is covered, the entire image still forms, though with reduced brightness. Therefore, this option is incorrect.
2. Image will show only half of the object: Since the lens still focuses the light from all parts of the object, the entire image is formed but with less intensity. Thus, the option stating that only half of the object is shown is incorrect.
3. Intensity of image gets reduced: By blocking half of the lens, we indeed reduce the amount of light that can pass through and form the image. This results in an image with reduced intensity. Therefore, this option aligns with the physical principle.

Based on the analysis, the correct solution is: (C) only

Answer 2

Let's analyze the effect of making the lower half of a convex lens opaque.

1. Image Formation in Convex Lens:

A convex lens forms an image by refracting light rays from the object. Every part of the lens contributes to forming the complete image.

2. Effect of Making Half Opaque:

When the lower half of the lens is made opaque, it blocks the light rays passing through that portion. However:

• The upper half of the lens still refracts light rays to form the complete image.
• The image will not show only half of the object because the entire lens is not needed to form the entire image.
• The intensity of the image will be reduced because fewer light rays are contributing to the image formation.

3. Analysis of Options:

• (A) No change in image: Incorrect. The intensity will change.
• (B) Image will show only half of the object: Incorrect. The full image is formed.
• (C) Intensity of image gets reduced: Correct.

Therefore, the correct answer is that the intensity of the image gets reduced.

The correct answer is:

Option 4: (C) only