The earth's magnetic dipole moment is 8*10^22 Am^2.
A. What is the magnetic field strength on the surface of the earth at the earth's north magnetic pole? You can assume that the current loop is deep inside the earth.
B. Astronauts discover an earth-size planet without a magnetic field. To create a magnetic field with the same strength as earth's, they propose running a current through a wire around the equator. What size current would be needed?