InterviewSolution
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InterviewSolution
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A domain in ferromagnetic iron in the form of cube shaving `5 xx 10^(10)` atoms. If the side length of this domain is `1.5mu` and each atom has a dipole moment of `8 xx 10^(-24)Am^(2)`, then magnetisation of domain isA. `11.8xx10^(5)Am^(-1)`B. `1.18xx10^(5)Am^(-1)`C. `11.8xx10^(4)Am^(-1)`D. `1.18xx10^(5)Am^(-1)` |
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Answer» Correct Answer - D The volume of the cubic domain is `V=(1.5xx10^(6)m)^(3)=3.38xx10^(-18)m^(3)=3.38xx10^(-12)cm^(3)` Number of atoms in doamain (N)=`5xx10^(10)"atoms"` Since each iron atoms has a dipole moment (m) `=8xx10^(-24)Am^(2)` `m_("max")`=total number of dipole moment for all atoms `=Nxxm` `=5xx10^(10)xx8xx10^(-24)` `=40xx10^(-14)=4xx10^(-13)Am^(2)` Now the consequent magnetisation `M_("max")=(m_("max"))/("Domain volume")=(4xx10^(-13)Am^(-2))/(3.38xx10^(-18)m^(3))` `=1.18xx10^(5)Am^(-1)` |
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