Q143 / 180 · AIIMS 2007 · Physics

Assertion : Ferro magnetic substances become paramagnetic above Curie temperature. Reason : Domains are destroyed at high temperature.

  • Correct answer
    A
    If both assertion and reason are true and reason is the correct explanation of assertion
  • B
    If both assertion and reason are true but reason is not the correct explanation of assertion
  • C
    If assertion is true but reason is false
  • D
    If both assertion and reason are false.

Solution

The assertion is true. From Curie Weiss law where the susceptibility \(\chi=\frac{C}{\left(T-\theta_C\right)}\). If the temperature rises above the Curie temperature \(\theta_C\), ferromagnetic materials become paramagnetic materials because the domains get destroyed as stated.

Hence, the correct answer is option: 'A'.

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