which of the following arrangements shows schematic alignment magnetic moments of antiferromagnetic substances?

Options

A.
B.
C.
D.

Explanation

To determine which arrangement shows the schematic alignment of magnetic moments of antiferromagnetic substances, we need to understand the characteristics of antiferromagnetism.

### Step-by-Step Solution:

1. **Understanding Antiferromagnetism**:
Antiferromagnetic substances are characterized by magnetic moments that are aligned in opposite directions. This means that for every magnetic moment pointing in one direction, there is another pointing in the opposite direction, resulting in a net magnetic field of zero.

2. **Identifying the Arrangement**:
We need to analyze the given arrangements (options) to see which one has the magnetic moments aligned in opposite directions.

3. **Analyzing Each Option**:
- **Option 1**: All magnetic moments are aligned in the same direction (e.g., all upward). This would result in a non-zero net magnetic field.
- **Option 2**: Similar to Option 1, all magnetic moments are aligned in the same direction. This is not characteristic of antiferromagnetic substances.
- **Option 3**: There are more magnetic moments pointing upward than downward (e.g., 4 upward and 2 downward). While some cancellation occurs, there is still a net magnetic field due to the excess upward moments.
- **Option 4**: There are equal numbers of magnetic moments pointing upward and downward (e.g., 3 upward and 3 downward). The upward moments cancel the downward moments, resulting in a net magnetic field of zero.

4. **Conclusion**:
Based on the analysis, **Option 4** is the correct arrangement that shows the schematic alignment of magnetic moments of antiferromagnetic substances, as it demonstrates equal and opposite orientations leading to a net magnetic field of zero.

### Final Answer:
**Option 4** shows the schematic alignment of magnetic moments of antiferromagnetic substances.