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Question
Find the magnetic field a distance r from the center of a long wire that has radius a and carries a
uniform current per unit area j in the positive z direction.
A.) First find the magnetic field,
B? out(r? ), outside the wire (i.e., when the distance r is greater than a). (Figure 1)
Express B? out(r? ) in terms of the given parameters, the permeability constant ?0, the
variables a, j (the magnitude of j? ), r, ?, and z, and the corresponding unit vectors r^, ?^, and k^. You
may not need all these in your answer.
B.)Now find the magnetic field
B? in(r? ) inside the wire (i.e., when the distance r is less than a).(Figure 2)
Express B? in(r? ) in terms of the given parameters, the permeability constant ?0, the distance r f rom
the center of the wire, and the unit vectors r^, ?^, and k^. You may not need all these in your answer.
Answer
