A sample of of paramagnetic salt contains ` 2.0xx10^(24)` atomic dipoles each of dipole moment `1.5xx10^(-23)JT^(-1)`. The sample is placed under a homogeneous magnetic field of 0.64 T , cooled to a temperature of 4.2 K . The degree of magnetic saturation achieved is equal to 15% . What is the total dipole moment of the sample for a magnetic field of 0.98 T and a temperature of 2.8 K ? (Assume Curie's law)

Explanation

`N=2.0xx10^(24) " "m=1.5xx10^(-23)JT^(-1) " "B_("ex")=0.84 T, T = 4.2 K`
% saturation = 15% , `sumNm` = ?
`=B=0.98T,T =2.8K`
Under the initial conditions , the total magnetic moment
`=1.5xx10^(-23)xx2.0xx10^(24)xx15/100=4.5JT^(-1)`
By Curie law, `M=C.B_0/T " " because m/V=C.(B_0)/T" "(m.)/V=C.(B)/(T.)`
`:.(m.)/m=B/(T.)xxT/B_0" ":.m.=(4.5xx0.98xx4.2)/(2.8xx0.84)=7.9JT^(-1)`