The resistivity of the material of a wire is 1.76 × 10-8 ωm. if the diameter of the wire is 2 × 10-3 m and its length is 2 m, what is its resistance?

The earth's magnetic field, with a magnetic dipole moment of 8.0×1022am2, is generated by currents within the molten iron of the earth's 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.to decide whether this is a large or a small current density, compare it to the current density of a 7.0 a current in a 2.0-mm-diameter wire.