(II) A long pair of wires conducts 25.0 $\mathrm{A}$ of de current to, and from, an instrument. If the insulated wires are of negligible diameter but are 2.8 $\mathrm{mm}$ apart, what is the magnetic field 10.00 $\mathrm{cm}$ from their midpoint, in their plane (Fig. $20-56 ) ?$ Compare to the magnetic field of the Earth.