Question

Constants 1 Periodic Table The figure (Figure 1) shows a solid wire of radius a surrounded by a cylindrical shell with inner radius b and thickness c. This setup is a good model for a "coax' cable that you might use with your television. The inner wire and the shell carry equal but opposite currents I, assumed to be uniformly distributed. Part A For the region inside the shell but outside the wire (a<r<b), find an expression for the magnitude of the magnetic field as a function of T. Express your answer in terms of the variables I, a, b, c, 7, and constant n. VAD O ? Moir BE Figure < 1 of 1 > |2na? Submit Previous Answers Request Answer X Incorrect; Try Again; 2 attempts remaining Part B Find an expression for the magnetic field strength as a function of radial position r beyond the outer conductor. Express your answer in terms of the variables I, a, b, c,r, and constant - B=0

Answer 1

A)
Consider an Amperian loop with a<r<b. The only current that is enclosed by the Ampereian loop is I, that flows through the inner wire.
Using Ampere's law,
B x 2$\pi$r = $\mu$o I
B = $\mu$oI / 2$\pi$r

B)
Consider an Amperian loop r > b+c
Total current enclosed by the Amperian loop = I - I = 0
Magnetic field = 0