A domain in a ferromagnetic substance is in the form of a cube of side length 1 `mu`m. If it contains `8 xx 10^(10)` atoms and each atomic dipole has a dipole moment of `9 xx 10^(-24) Am^(2)`, then magnetization of the domain is

Options

A. `7.2xx10^(5) Am^(-1)`
B. `7.2xx10^(3) Am^(-1)`
C. `7.2xx10^(9)Am^(-1)`
D. `7.2XX10^(12)aM^(-1)`

Answer

a

Explanation

(a) The volume of the cube is
`V=(10^(-6)m)^(3)=10^(-18)m^(3)`
Net dipole moment `m_("net")8xx10^(10)xx9xx10^(-24)Am^(2)`
`=72xx10^(-14)Am^(2)`
Intensity of magnetization is magnetic moment developed per unit volume.
`therefore` Magnetization, `M=(m_("net"))/("vlome")`
`=(72xx10^(-14)Am^(2))/(10^(-18m^(3))=72xx10^(4)Am^(-1)=7.2xx10^(5)Am^(-1)`