(Solved): A thin (radius r=1.125mm ) long wire is used to build a solenoid: the wire is densely (subsequent ...

A thin (radius $r=1.125\mathrm{mm}$ ) long wire is used to build a solenoid: the wire is densely (subsequent turns touching each other) wound around a cylindrical surface of the diameter $D=2.8\mathrm{cm}$. When electric current $I=3.3$ A runs in this wire, what is the magnitude $B_{\text{sol }}$ of the magnetic field in the center of the solenoid?: $B_{\text{sol }}=$ Let us now compare that magnetic field to the magnetic field $B_1$ that would be produced just by a single circular loop of this wire at circle's center (with the same diameter $D$ and running the same current $I$ ): $B_1/B_{\text{sol }}=$