Wolfram Demonstrations Project: "Magnetic Field Energy in Inductors"

This demonstration provides examples for both capacitors and inductors, but work only with the inductors for now. Treat this demonstration as a laboratory experiment in which you measure the inductance of various geometries and confirm from theory that the values are correct. Get the electromagnetic field energy generated by applied current from the demonstration, and confirm them by direct calculation based on the theoretical relations listed here and in the lectures and readings above. First, calculate the inductance of the coil, using the formula given in the description in the demonstration, or the readings above. Then, calculate current through the inductor using Ohm’s Law, and magnetic field created by this current. Finally, calculate the magnetic energy stored in the inductor, and the magnetic energy density. Again, confirm your result.

You can also explore this demonstration conceptually, to get a feel for how the magnetic field inside the coil and magnetic energy density are affected by the geometry of the inductor, resistance, and applied voltage. Vary each of the parameters in turn and observe the changes in B and ρ. Why does not the magnetic field depend on the radius of the coil?