The magnetic moment produced in a substance of `1 gm is 6xx10^(-7) "ampere","metre"^(2)`. If its density is `5 gm//cm^(3)`, then the intensity of magnetisation in `A//m` will be

Options

A. `8.3xx10^(6)`
B. `3.0`
C. `1.2xx10^(-7)`
D. `3xx10^(-6)`

Answer

B

Explanation

`I=m/V=M/(mass//density)`,
given `mass=1 gm=10^(-3) kg`, and density
`=5 gm//cm^(3)=(5xx10^(-3)kg)/((10^(-2))m^(3))=5xx10^(3) kg//m^(3)`
Hence `I=(6xx10^(-7)xx5xx10^(3))/10^(-3)=3`