find all the bound currents. What is the net bound current flowing down the wire?

by blueyellow
Tags: bound, current, currents, flowing, wire
blueyellow is offline
Nov12-11, 07:39 AM
P: 241
1. The problem statement, all variables and given/known data

A current I flows down a long straight wire of radius a. The wire is made of linear material with susceptibility chi(subscript m), and the current is distributed uniformly.

i) what is the magnetic field a distance s from the axis?
ii) Find all the bound currents. What is the net bound current flowing down the wire?

3. The attempt at a solution
i) I found a similar homework question on this website:

which says that B=[mu Is/(2pi a^2)]phi-hat
ii) J(subscript M)= curl M
= [(chi(subscript M) I)/(pi a^2)] z-hat

integral of [(chi(subscript M) I)/(pi a^2)] z-hat dS
= loop integral of [(chi(subscript M) I)/(pi a^2)] z-hat. dl

why does J(subscript M) have to be integrated over the surface, though?

j(subscript m)=M cross n-hat
=[- chi(subscript M) Is/(2 pi a^2)]z-hat ?

why does
say that j(subscripr m) has to be integrated over the perimeter? How do I do this? And why is the result of it supposed to be zero? Please help
Phys.Org News Partner Science news on
Going nuts? Turkey looks to pistachios to heat new eco-city
Space-tested fluid flow concept advances infectious disease diagnoses
SpaceX launches supplies to space station (Update)

Register to reply

Related Discussions
Equivalence between bound electric currents & bound magnetic charge in magnetization Classical Physics 6
Quick question regarding bound currents. Classical Physics 2
How do we find the least upper bound and greatest lower bound? Calculus & Beyond Homework 2
bound currents problem Advanced Physics Homework 2
Bound currents Classical Physics 2