If the lower half of a concave mirror's reflecting surface is made opaque, which of the following statements describe the image of an object placed in front of the mirror ?
S1 : Intensity of the image will increase.
S2 : The image will show only half of the object.
S3 : No change in the image.
S4 : Intensity if the image will be reduced to half.

Options

A. S1 only
B. S2 only
C. S2 and S3
D. S4 only

Explanation

To solve the question regarding the effect of making the lower half of a concave mirror opaque on the image formed by an object in front of it, we can analyze each statement provided in the question.

### Step-by-Step Solution:

1. **Understanding the Setup**:
- We have a concave mirror, and we are making the lower half of its reflecting surface opaque. This means that this part of the mirror will not reflect any light.

2. **Analyzing the Image Formation**:
- A concave mirror can form a real or virtual image depending on the position of the object. However, regardless of the position of the object, the image formed will always be complete. This is because the rays of light from the object will still be reflected by the upper half of the mirror.

3. **Evaluating Each Statement**:
- **S1: Intensity of the image will increase**: This statement is incorrect. The intensity of the image is related to the amount of light that is reflected to form the image. Since half of the mirror is opaque, the total amount of light reflected will decrease, leading to a decrease in intensity.

- **S2: The image will show only half of the object**: This statement is also incorrect. The image will still be complete, showing the entire object, even though only half of the mirror is reflecting.

- **S3: No change in the image**: This statement is misleading. While the image will still be complete, the intensity will change due to the reduced reflecting area. Therefore, this statement is not entirely accurate.

- **S4: Intensity of the image will be reduced to half**: This statement is the most accurate. Since half of the mirror is not reflecting light, the intensity of the image will be reduced, but it may not necessarily be exactly half, depending on the distribution of light rays. However, it is reasonable to conclude that the intensity will be reduced.

4. **Conclusion**:
- The correct statement regarding the image formed by the concave mirror when the lower half is made opaque is that the intensity of the image will be reduced, but the image will remain complete.

### Final Answer:
- The correct statement is **S4: Intensity of the image will be reduced to half**.