Talk:Magnetic induction: Difference between revisions
imported>John R. Brews (→Magnetic field B is a force?: Changes made.) |
imported>John R. Brews (→Magnetic field B is a force?: fix quote from older version) |
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== Magnetic field B is a force? == | == Magnetic field B is a force? == | ||
The intro says " | The intro says "magnetic induction (also known as magnetic flux density) describes a magnetic force..." That is a misstatement, as the ''force'' on a moving charge is the Lorentz force '''F''' = q ('''v × B''').[http://books.google.com/books?id=93E_vYuCKHYC&pg=PA277&dq=%22Lorentz+force%22+electromagnetism&hl=en&ei=ZNsATdC_JIrSsAPGmaiwCw&sa=X&oi=book_result&ct=result&resnum=5&sqi=2&ved=0CD4Q6AEwBA#v=onepage&q&f=false 1] | ||
From a microscopic standpoint, the magnetic field '''B''' is fundamental because it determines the effects upon the dynamics of the charges. The magnetic field intensity (or whatever you want to call it) '''H''' is a derived quantity '''H''' = '''B'''/μ<sub>0</sub> − '''M'''. The magnetization '''M''' is determined by decisions about the level of detail one needs in describing ensembles of charges, and so is really a decision about how coarsely one can deal with portions of a system of charges, lumping some of them together in an ensemble as a "magnetic material". [[User:John R. Brews|John R. Brews]] 13:48, 9 December 2010 (UTC) | From a microscopic standpoint, the magnetic field '''B''' is fundamental because it determines the effects upon the dynamics of the charges. The magnetic field intensity (or whatever you want to call it) '''H''' is a derived quantity '''H''' = '''B'''/μ<sub>0</sub> − '''M'''. The magnetization '''M''' is determined by decisions about the level of detail one needs in describing ensembles of charges, and so is really a decision about how coarsely one can deal with portions of a system of charges, lumping some of them together in an ensemble as a "magnetic material". [[User:John R. Brews|John R. Brews]] 13:48, 9 December 2010 (UTC) | ||
I made some changes to reflect these remarks. [[User:John R. Brews|John R. Brews]] 14:33, 9 December 2010 (UTC) | I made some changes to reflect these remarks. [[User:John R. Brews|John R. Brews]] 14:33, 9 December 2010 (UTC) | ||
Latest revision as of 11:08, 9 December 2010
Magnetic field B is a force?
The intro says "magnetic induction (also known as magnetic flux density) describes a magnetic force..." That is a misstatement, as the force on a moving charge is the Lorentz force F = q (v × B).1
From a microscopic standpoint, the magnetic field B is fundamental because it determines the effects upon the dynamics of the charges. The magnetic field intensity (or whatever you want to call it) H is a derived quantity H = B/μ0 − M. The magnetization M is determined by decisions about the level of detail one needs in describing ensembles of charges, and so is really a decision about how coarsely one can deal with portions of a system of charges, lumping some of them together in an ensemble as a "magnetic material". John R. Brews 13:48, 9 December 2010 (UTC)
I made some changes to reflect these remarks. John R. Brews 14:33, 9 December 2010 (UTC)