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

Options

A. Both A and Rare Tuę and R is the correct explanation of A
B. Both A and R are true but R is NOT the correct explanation of A
C. A is true but R is false
D. A is false and R is true

Answer

A

Explanation

From Curie Weiss law,
`chi =(C )/(T – T _(C))`
As temperature increases beyond Curie temperature, susceptibility decreases and the ferromagnetic substances become paramagnetic. So, the assertion is true. Paramagnetic substance has no magnetic domain. At a very high temperature, the domains of ferromagnetic substance get destroyed and the substance transforms into paramagnetic substance. So, the reason is also true and properly explains the assertion.