Question

The susceptibility of a ferromagnetic material is found to be X at a temperature of 27°C. Its susceptibility at 627 °C will be __________.
1. 3X
2. X/3
3. 2X
4. X/2

Answer 1

Correct Answer - Option 2 : X/3

CONCEPT:

• The magnitude of the internal polarization (J) divided by the strength of the external field (B) is called Magnetic susceptibility. 
• It is denoted by the Greek letter chi (χ).
• Ferromagnetic materials follow the Curie – Weiss law.
• When ferromagnetic substance heated above Curie temperature (Tc) 

\(i.e.\;χ \propto \frac{1}{{T - {T_C}}}\)

where T-Tc is the temperature and χ is susceptibility.

CALCULATION:

Given that T₁ = 27 + 273 = 300 K

T₂ = 27 + 627 = 900 K

Since we know that \(i.e.\;χ \propto \frac{1}{{T}}\)

\(\;\frac{χ_1}{χ_2} = \frac{T_2}{{T_1}}\)

\(\;\frac{χ}{χ_2} = \frac{900}{300}\)

χ₂ = χ/3

• So, the answer will be option 2.