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Algumas Evidências Experimentais
Mais Evidências Experimentais
http://efisica.if.usp.br/eletricidade/basico/campo_corrente/exper_oersted/
Campos MagnéticosMagnetic Fields are produced by electric currents, which can be macroscopic
currents in wires, or microscopic currents associated with electrons in atomic orbits. The magnetic field B is defined in terms of force on moving charge in the Lorentz force law. The interaction of magnetic field with charge leads to many practical applications. Magnetic field sources are essentially dipolar in nature, having a north and south magnetic pole. The SI unit for magnetic field is the Tesla, which can be seen from the magnetic part of the Lorentz force law Fmagnetic = qvB to be composed of (Newton x second)/(Coulomb x meter).
A smaller magnetic field unit is the Gauss (1 Tesla = 10,000 Gauss)
http://hyperphysics.phy-astr.gsu.edu/hbase/magnetic/magfie.html
Força X Campo Magnético
F qvB
F qv B
F qvBsen
Linhas de Campo Magnético e Fluxo Magnético.
Bd B dA r rg
B dA 0r rgÑ
Em alguns casos:
BdB
dA
Movimento de Partículas Carregadas em um Campo Magnético
A força magnética é perpendicular à velocidade -> não pode alterar seu módulo.
2vF q vB m força centripeta
R
mvR
q B
q Bvw
R m
Força de Lorentz
http://www.lon-capa.org/~mmp/kap21/cd533capp.htm
http://uk.geocities.com/pvd_coatings/theory2.htm
http://musr.physics.ubc.ca/~jess/hr/skept/E_M/node8.html
F q(E v B)
Seletor de VelocidadesqE qvB 0
Ev
B
Experiência de Thompson
Pgs 209 e 210.
Força sobre um Condutor de Corrente.
n cargas por unidade de volume.
totalF q vB nAlqvB
I nAqv F IlB
F I l B
Para um pedaço de fio:
dF Idl B
http://images.google.com.br/imgres?imgurl=http://static.howstuffworks.com/gif/railgun-7.gif&imgrefurl=http://science.howstuffworks.com/rail-gun1.htm&h=370&w=401&sz=15&hl=pt-BR&start=1&um=1&tbnid=ra_W8y1T4L63sM:&tbnh=114&tbnw=124&prev=/images%3Fq%3DLorentz%2BForce%26svnum%3D10%26um%3D1%26hl%3Dpt-BR%26sa%3DN
Força e Torque sobre uma Espira de Corrente
22
b
F sen IBabsen IBAsen
rrgU B