Suppose that the source of earth's magnetism is a magnetic dipole at the earth. Find the moment of this magnetic dipole if the strength of earth's magnetic field at the equator is `4xx10^(-5)` T . Given , radius of the earth `6.4xx10^(6)mand(mu_(0))/(4pi)=10^(-7)T.m.A^(-1)`.

Options

A. `10^(23) Am^(2)`
B. `10^(20) Am^(2)`
C. `10^(16) Am^(2)`
D. `10^(10) Am^(2)`

Answer

a

Explanation

(a) Given, `B=4xx10^(-5)T`
`R_(E)=6.4xx10^(6)m`
Dipole moment of the earth M=?
`B=(mu_(0))/(4pi)(M)/(d^(3))`
`4xx10^(-5)=(4pixx10^(-7)xxM)/(4pixx(6.4xx10^(6))^(3)) therefore M=~10^(23)Am^(2)`