7. Assertion : On heating ferromagnetic or ferrimagnetic substances, they become paramagnetic. Reason : The electrons change their spin on heating.

a. If both assertion and reason are true and the reason is the correct explanation of the assertion

b. If both assertion and reason are true but reason is not the correct explanation of the assertion

c. If assertion is true but reason is false

d. If the assertion and reason both are false

e. if assertion is false but reason is true.

Ans. a

Explanation : All magnetically ordered solids transform to the paramagnetic state at high  temperature due to the randomisation of spins.

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