The earth's magnetic field at the equator is approximately `0*4G`, Estimate the earth's dipole moment.

Options

A. `1.05xx10^(23)Am^(2)`
B. `2.05xx10^(23)Am^(2)`
C. `1.05xx10^(21)Am^(2)`
D. `2.05xx10^(21)Am^(2)`

Answer

A

Explanation

Here, `B_(E)=0.4G=0.4xx10^(-4)T`
`r=6.4xx10^(6)m`
`"As", B_(E)=(mu_(0))/(4pi)(m)/(r^(3))`
`therefore m=(B_(E)r^(3))/(mu_(0)//4pi)=(0.4xx10^(-4)xx(6.4xx10^(6))^(3))/(10^(-7))`
`=1.05xx10^(23)Am^(2)`