The earths magnetic field, with a magnetic dipole moment
Chapter 29, Problem 29.89(choose chapter or problem)
The earths magnetic field, with a magnetic dipole moment of 8.0 * 1022 Am2 , is generated by currents within the molten iron of the earths outer core. Suppose we model the core current as a 3000-km-diameter current loop made from a 1000-km-diameter wire. The loop diameter is measured from the centers of this very fat wire. a. What is the current in the current loop? b. What is the current density J in the current loop? c. To decide whether this is a large or a small current density, compare it to the current density of a 1.0 A current in a 1.0-mm-diameter wire
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