Experiências de Indução.

Cuidado !!!

Lei de Faraday

http://ocw. mit. edu/ans7870/8/8 http://ocw.mit.edu/ans7870/8/8.02T/f04/visualizations/faraday/15-inductance/15-1_wmv320.html http://ocw.mit.edu/ans7870/8/8.02T/f04/visualizations/faraday/15-inductance/1_edit.wmv

A fem induzida em uma espira é dada pela taxa de variação do fluxo magnético, com o sinal negativo, através da área delimitada pela espira.

Repare que o campo magnético gerado se opõe a variação do que o gera. Para N espiras:

Lei de Lenz O sentido de qualquer efeito de indução magnética é tal que se opõe a causa que produz este efeito. Want A More Exciting Experiment? A more elaborate experiment that demonstrates the same scientific principles can be done with a solenoid wrapped around a pop can. When the switch is closed. a capacitor in the circuit is discharged through the solenoid. Since the current varies in time, the magnetic field in the solenoid and the magnetic flux defined in the solenoid will vary in time. This variable flux also passes through the can inside the solenoid, inducing in it a current in opposite direction of the current through the solenoid (Lenz's Law). The two antiparallel currents repel each other, and since the solenoid is fixed the can will be crushed. http://www.ndt-ed.org/TeachingResources/NDT_Tips/LenzLaw.htm You Tube: http://www.youtube.com/watch?v=wt3It6d1o_Y

Força Eletromotriz Produzida pelo Movimento As cargas se acumulam na extremidade da haste até que:

A haste funciona como um gerador de fem. Lembrete: Não vale para condutores em repouso em um campo magnético variável.

Campos Elétricos Induzidos

Campos Elétricos Induzidos

Faraday's law of induction gives the relation between the rate of change of the magnetic flux through the area enclosed by a closed loop and the electric field induced along the loop: where ΦB is the magnetic flux through the area A described by the second equation E is the electric field generated by the magnetic flux s is a closed path in which current is induced, such as a wire. Or, in differential form in terms of magnetic field B: Note the negative sign; it is necessary to maintain conservation of energy. It is so important that it even has its own name, Lenz's law.

Equações de Maxwell I. Gauss' law for electricity                       I. Gauss' law for magnetism                     III. Faraday's law of induction                            IV. Ampere's law                                             http://hyperphysics.phy-astr.gsu.edu/hbase/electric/maxeq.html#c2

Ache o erro: http://lizti.br.tripod.com/maxwell_na_forma_int.htm

http://plato.if.usp.br/~fap2292d/NotasDeAula3.pdf

Equações de Maxwell

Exercícios Todos os problemas do capítulo 30.