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. `3 xx 10^(-6)`

Answer

B

Explanation

Intensity of magnetisation , `l=(M)/V=-(M)/("mass/density")`
Given , mass =1 g =`10^(-3)kg ` and density ` =5g//cm^(3)=(5 xx 10^(-3)kg)/((10^(-2))^(3))=5 xx 10^(3) kg m^(-3)`
Hence , `l=( 6xx 10^(-7) xx 5 xx 10^(3))/( 10^(-3))=3Am^(-1)`