Temperature above which a ferromagnetic substance becomes paremagnetic is called

Options

A. neutral temperature
B. Curie temperature
C. inversion temperature
D. critical temperature

Answer

To solve the question regarding the temperature above which a ferromagnetic substance becomes paramagnetic, we need to identify the correct term from the given options: neutral temperature, Curie temperature, inversion temperature, and critical temperature.

### Step-by-step Solution:

1. **Understanding Ferromagnetism and Paramagnetism**:
- Ferromagnetic materials exhibit strong magnetic properties due to the alignment of magnetic moments in the same direction.
- Paramagnetic materials have unpaired electrons that align with an external magnetic field but do not retain magnetization in the absence of the field.

2. **Identifying the Transition Point**:
- There is a specific temperature at which ferromagnetic materials lose their magnetic properties and transition to a paramagnetic state. This temperature is crucial for understanding the behavior of magnetic materials.

3. **Defining the Curie Temperature**:
- The temperature at which this transition occurs is known as the **Curie temperature (Tc)**. Below this temperature, the material remains ferromagnetic, and above it, the material becomes paramagnetic.

4. **Analyzing the Options**:
- The options provided are:
- Neutral temperature
- Curie temperature
- Inversion temperature
- Critical temperature
- Among these, the **Curie temperature** is the term specifically used to describe the transition from ferromagnetic to paramagnetic behavior.

5. **Conclusion**:
- Therefore, the correct answer to the question is **Curie temperature**.

### Final Answer:
The temperature above which a ferromagnetic substance becomes paramagnetic is called the **Curie temperature**.

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