Chapter 30201P30.40BnINrI==FHGIKJµµπ2so IrBN×⋅=−220 1001 305 000 4104702777µbgafafejaf..m TWb A mmAP30.41Assuming a uniform Binside the toroid is equivalent to assumingrR<<; then BNIR002≈as for a tightlywound solenoid.B630 3 0020200000189afaf... TWiththe steel, BBBm+=κχ1101 0 001 89TB=0191TFIG. P30.41P30.42CTMB××=×⋅⋅−4 0010 0% 8 00 105 00 9 27 10500297 1027244.....K atomsJTTKJTm3223afP30.43BHM=+0soHBM=−=×06262 10AmP30.44In M0we have 2 000T=M. But also MxnB=. Then BxnB=0where nis thenumber of atoms per volume and xis the number of electrons per atom contributing.ThenxBnB⋅×⋅=−−−047200927 10410202...T8.50 10 mN m TT m A28ejej.P30.45(a)Comparing Equations 30.29 and 30.30, we see that the applied field is described by=. Then Eq. 30.35 becomes MCBTCTH00, and the definition of susceptibility(Eq. 30.32) is χµMHCT0.(b)CT×⋅⋅−−χ0474270 10300410645 10..KTmAKASection 30.9The Magnetic Field of the Earth
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This note was uploaded on 12/14/2011 for the course PHY 203 taught by Professor Staff during the Fall '11 term at Indiana State University .