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Lei de Gauss - Fotoacustica.fis.ufba.br

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UNIVERSIDADE TECNOLÓGICA FEDERAL DO PARANÁ<<strong>br</strong> />

DISCIPLINA: FÍSICA 3<<strong>br</strong> />

2 a Lista <strong>de</strong> Exercícios<<strong>br</strong> />

<strong>Lei</strong> <strong>de</strong> <strong>Gauss</strong><<strong>br</strong> />

1. Usando a lei <strong>de</strong> <strong>Gauss</strong>, calcule o campo elétrico produzido por:<<strong>br</strong> />

(a) um fio cilíndrico infinito e <strong>de</strong>nsida<strong>de</strong> linear <strong>de</strong> cargas λ<<strong>br</strong> />

(b) uma carga uniformemente distribuída so<strong>br</strong>e um plano <strong>de</strong> <strong>de</strong>nsida<strong>de</strong> superficial σ,<<strong>br</strong> />

(c) dois planos paralelos com cargas iguais e opostas<<strong>br</strong> />

(d) uma fina casca esférica carregada <strong>de</strong> raio R e carga total Q<<strong>br</strong> />

1


(e) uma esfera sólida uniformemente carregada que tem raio R<<strong>br</strong> />

e uma carga total Q, distribuída uniformemente através do<<strong>br</strong> />

volume da esfera cuja <strong>de</strong>nsida<strong>de</strong> <strong>de</strong> carga é ρ=Q/V on<strong>de</strong><<strong>br</strong> />

V π<<strong>br</strong> />

3<<strong>br</strong> />

= 4 / 3 R é o volume da esfera.<<strong>br</strong> />

Resp: (a) λ<<strong>br</strong> />

E = (b) σ<<strong>br</strong> />

E = (c) E = 0 ,0 para xd e σ<<strong>br</strong> />

E = iˆ<<strong>br</strong> />

para 0 R<<strong>br</strong> />

0<<strong>br</strong> />

0<<strong>br</strong> />

Q<<strong>br</strong> />

E =<<strong>br</strong> />

4πε r<<strong>br</strong> />

2<<strong>br</strong> />

, r

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