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The earth magnetic field at the equator is approximately 04.G. Estimate the earth's dipole moment. |
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Answer» Solution :From Eq (5.7), the equatorial magnetic field is `B_(E)=(mu_(0)m)/(4pi R^(3))` We are given that `B_(E)-0.4G=4 xx 106(-5)T.` For r we take the radius of the earth `6.4 xx 10^(6) m`. Hence `m=(4 xx 10^(-5) xx (6.4 xx 10^(6))^(3))/(mu_(0)//4pi)=4 xx 10^(2) xx (6.4 xx 10^(6))^(3) (mu_(0)//4pi=10^(-7))` `=1.05 xx 10^(23) Am^(2)` This is close to the VALUE of `8 xx 10^(22) A m^(2)` quoted in geomegnetic TEXTS. |
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