Physics 307 Homework
 RU Links   Radford University   Department of Physics   RU Planetarium   RUSMART pages (weather) Spring 2013 Classes & Info   PHYS 112   PHYS 307   PHYS/GEOL 406   My daily schedule   My C.V. Summer jobs/internships   NSF REU Program (list of REU sites) Other links   The Nucleus (resources for    physics/astronomy undergrads)   Pre-Health information   R.U.F.R.E.E.Z.I.N.G.    pics from the north pole trip    the picture from the trip   Simple 2-liter water rocket   American Institute of Physics Homework #9: Do not turn this in since there is a test next week during the lab times on Tuesday, April 9. I will post my solutions so that you can check your own work. A wire has within it a current density given by J=J0r3z where the boldface z is the z unit vector, and J0=2,500Amp/m5. This will make the current bunch up towards the edges of the wire. The radius of the wire is 0.20cm. Find (a) the magnitude of the magnetic field at a distance of 0.12cm from the axis of the wire, and (b) the magnitude of the magnetic field at a distance of 0.35cm from the axis of the wire. (Note that this is just a slightly more complicated version of problem 6.2 in the text.) A hollow wire has within it a current density given by J=J0r3z where the boldface z is the z unit vector, and J0=2,500Amp/m5. The radius of the hollow part of the wire is 0.10cm; the radius of the wire itself is 0.20cm. Find (a) the magnitude of the magnetic field at a distance of 0.12cm from the axis of the wire, and (b) the magnitude of the magnetic field at a distance of 0.35cm from the axis of the wire. Here is a magnetic field vector: B={Cx*sin(x⋅y),Cy*cos(y2)} (Mathematica vector notation). Find the general form of the vector current density J associated with this field. There is no electric field present. Two wires are lying in an east-west direction. One wire has a current of 4.5A running through it going to the east. The other wire is hanging 55cm below the first, and has a current of 3.5A running through it going to the west. Find the (a) magnitude and (b) direction of the magnetic field a distance of 1.70m below the lower wire. Refer to fig. 6.43 on p. 334 for this problem. Find the strength of the magnetic field at (a) a point 2.5cm above point P, and (b) 6.0cm above point P.    That's all for homework #9.