A paramagnetic sample shows a net magnetisation of `8Am^-1` when placed in an external magnetic field of `0*6T` at a temperature of `4K`. When the same sample is placed in an external magnetic field of `0*2T` at a temperature of `16K`, the magnetisation will be

Options

A. `32/3Am^(-1)`
B. `2/3Am^(-1)`
C. `6Am^(-1)`
D. `2.4Am^(-1)`

Answer

B

Explanation

As curie law explains, we can deduce a formula for the relation between magnetic field induction, temperature and magnetisation.
i.e.,
`I("magnetisation")oo(B("magnetic field induction"))/(t("temperature in kelvin"))`
`rArrI_(2)/I_(1)=B_(2)/B_(1)xxt_(1)/t_(2)`
Let us suppose, here `I_(1)=8Am^(-1)`
`B_(1)=0.6T,t_(1)=4K`
`B_(2)=0.2T,t_(2)=16K`
`I_(2)=?`
`rArr0.2/0.6xx4/16=I_(2)/8`
`rArrI_(2)=8xx1/12=2/3Am^(-1)`