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Question:

A paramagnetic material has 1028 atoms/m3. Its magnetic susceptibility at temperature 350 K is 2.8 × 10-8. Its susceptibility at 300 K is:

3.726 × 10-8

2.672 × 10-8

3.267 × 10-8

3.672 × 10-8

Solution:

The correct option is C 3.267 × 10-8
χ ∝ 1/T (Curie law for paramagnetic substance)
χ1T1 = χ2T2
(2.8 × 10-8)(350) = χ2(300)
χ2 = (2.8 × 10-8)(350)/300
χ2 = 3.267 × 10-8