The Question is from NEET guide , and it was created by the author P.NARASIMHA

Question

A ferromagnetic material with Curie temperature $T_C$ is heated to a temperature $T > T_C$.  Which of the following best describes its magnetic susceptibility ($\chi$) at temperature $T$?

P.NARASIMHA · Accepted Answer

## CORE INFORMATION
✓ **Answer**: D
## CONCEPT FRAMEWORK
 **Primary Concept**: Curie-Weiss Law and Paramagnetism
 **Related Topics**: Ferromagnetism, Curie Temperature, Magnetic Susceptibility
 **Prerequisites**: Understanding of ferromagnetism, paramagnetism, and the Curie-Weiss law.
## SOLUTION PATHWAY
**Given Information**:
  * Ferromagnetic material
  * Temperature $T > T_C$ (Curie temperature)
  * We need to determine the magnetic susceptibility $\chi$
**Method & Steps**:
 1. **Understanding Curie Temperature ($T_C$)**: The Curie temperature is the critical temperature above which a ferromagnetic material loses its spontaneous magnetization.  Above $T_C$, the material becomes paramagnetic.
  Reasoning:  At temperatures below $T_C$, the material exhibits spontaneous magnetization due to the alignment of magnetic domains. Above $T_C$, thermal energy overcomes the exchange interactions responsible for this alignment, leading to a loss of spontaneous magnetization.
  Formula/Rule: None directly applied in this step.
 2. **Paramagnetic Behavior Above $T_C$**: Above the Curie temperature, the material behaves paramagnetically.  Paramagnetic materials have a positive magnetic susceptibility.
  Working:  In paramagnetic materials, the magnetic moments align themselves with the applied magnetic field, leading to a positive magnetization.  The susceptibility is positive and relatively small.
  Key Point: The material is no longer ferromagnetic above $T_C$.
 3. **Curie-Weiss Law**: The Curie-Weiss law describes the magnetic susceptibility of a paramagnetic material above its Curie temperature:
$\chi = \frac{C}{T - T_C}$
where $C$ is the Curie constant and $T$ is the absolute temperature.  This shows that the susceptibility is small and positive above $T_C$.
  Result: The magnetic susceptibility is small and positive, following the Curie-Weiss law.
  Verification: The Curie-Weiss law is a well-established model for paramagnetic behavior above the Curie temperature.
 ## OPTION ANALYSIS
A :x: Above $T_C$, the susceptibility is not large; it's small due to the weakening of the magnetic interactions.
B :x: Paramagnetic materials have positive susceptibility.
F :x: Paramagnetic materials have positive susceptibility.
D ✓: This is the correct description, accurately reflecting the paramagnetic behavior and the Curie-Weiss law.
 ## LEARNING AIDS
 **Common Mistakes**:
  1.Confusing ferromagnetic and paramagnetic behavior: Remember that above $T_C$, the material is paramagnetic, not ferromagnetic.
  2.Assuming large susceptibility:  The susceptibility is small and positive above $T_C$, not large.
 **Quick Tips**:
  1.Remember the Curie-Weiss law as a key tool for understanding paramagnetic susceptibility above $T_C$.
  2.Visualize the alignment of magnetic moments: Above $T_C$, thermal energy disrupts the alignment, resulting in weak, positive susceptibility.

P.NARASIMHA · Answer

$\chi$ is large and positive.

P.NARASIMHA · Answer

$\chi$ is small and negative.

P.NARASIMHA · Answer

$\chi$ is large and negative.

P.NARASIMHA · Answer

The correct Option is "$\chi$ is small and positive, following the Curie-Weiss law."

NEET Questions

Select Subject

Question Tags

Question Tags

Question Tags

Question Tags

Question Tags

Question Tags

Question Tags

Question Tags

Question Tags

Question Tags

NEET Subjects

Our Bots

Company