{"id":1640,"date":"2015-12-19T14:29:17","date_gmt":"2015-12-19T14:29:17","guid":{"rendered":"http:\/\/fisicaevestibular.com.br\/novo\/?page_id=1640"},"modified":"2024-08-20T15:42:22","modified_gmt":"2024-08-20T15:42:22","slug":"exercicios-de-vestibulares-com-resolucoes-comentadas-sobre-linhas-de-forca-de-campo-e-potencial-eletrostatico","status":"publish","type":"page","link":"https:\/\/fisicaevestibular.com.br\/novo\/eletricidade\/eletrostatica\/linhas-de-forca-de-campo-de-um-campo-eletrico-potencial-eletrostatico\/exercicios-de-vestibulares-com-resolucoes-comentadas-sobre-linhas-de-forca-de-campo-e-potencial-eletrostatico\/","title":{"rendered":"Linhas de For\u00e7a e Potencial Eletrost\u00e1tico – Resolu\u00e7\u00e3o"},"content":{"rendered":"

Exerc\u00edcios de vestibulares com resolu\u00e7\u00f5es comentadas sobre<\/b><\/span><\/span><\/span><\/p>\n

Linhas de For\u00e7a (de campo) e Potencial Eletrost\u00e1tico<\/b><\/span><\/span><\/span><\/p>\n

01-(UFPA)<\/b><\/span><\/span><\/span> Com rela\u00e7\u00e3o \u00e0s linhas de for\u00e7a de um campo el\u00e9trico, pode-se afirmar que s\u00e3o linhas imagin\u00e1rias:\u00a0<\/b><\/span><\/span><\/span><\/p>\n

\u00a0a) tais que a tangente a elas em qualquer ponto tem a mesma dire\u00e7\u00e3o do campo el\u00e9trico;<\/b><\/span><\/span><\/span><\/p>\n

\u00a0b) tais que a perpendicular a elas em qualquer ponto tem a mesma dire\u00e7\u00e3o do campo el\u00e9trico;<\/b><\/span><\/span><\/span><\/p>\n

\u00a0c) que circulam a dire\u00e7\u00e3o do campo el\u00e9trico;<\/b><\/span><\/span><\/span><\/p>\n

\u00a0d) que nunca coincidem com a dire\u00e7\u00e3o do campo el\u00e9trico;<\/b><\/span><\/span><\/span><\/p>\n

\u00a0e) que sempre coincide com a dire\u00e7\u00e3o do campo el\u00e9trico. \u00a0<\/b><\/span><\/span><\/span><\/p>\n

\u00a0<\/span><\/p>\n

02-(UFES)<\/b><\/span><\/span><\/span> As linhas de for\u00e7a do conjunto de cargas Q<\/b><\/span><\/span><\/span>1<\/b><\/span><\/span><\/sub><\/span>\u00a0<\/b><\/span><\/span><\/span>e Q<\/b><\/span><\/span><\/span>2<\/b><\/span><\/span><\/sub><\/span>\u00a0<\/b><\/span><\/span><\/span>s\u00e3o mostradas na figura.<\/b><\/span><\/span><\/span><\/p>\n

\"\"<\/p>\n

Para originar essas linhas, os sinais de Q<\/b><\/span><\/span><\/span>1<\/b><\/span><\/span><\/sub><\/span>\u00a0<\/b><\/span><\/span><\/span>e Q<\/b><\/span><\/span><\/span>2<\/b><\/span><\/span><\/sub><\/span>\u00a0<\/b><\/span><\/span><\/span>devem ser, respectivamente:<\/b><\/span><\/span><\/span><\/p>\n

\"\"<\/p>\n

\u00a0<\/span><\/p>\n

03-(UNICAMP-SP)<\/b><\/span><\/span><\/span> A figura mostra as linhas de for\u00e7a de um campo eletrost\u00e1tico criado por um<\/b><\/span><\/span><\/span><\/p>\n

\"\"<\/p>\n

sistema de duas cargas puntiformes q<\/b><\/span><\/span><\/span>1<\/b><\/span><\/span><\/sub><\/span>\u00a0<\/b><\/span><\/span><\/span>e q<\/b><\/span><\/span><\/span>2<\/b><\/span><\/span><\/sub><\/span>.<\/b><\/span><\/span><\/span><\/p>\n

a) Nas proximidades de que carga o campo eletrost\u00e1tico \u00e9 mais intenso? Por qu\u00ea?<\/b><\/span><\/span><\/span><\/p>\n

b) Qual \u00e9 o sinal do produto q<\/b><\/span><\/span><\/span>1<\/b><\/span><\/span><\/sub><\/span>.q<\/b><\/span><\/span><\/span>2<\/b><\/span><\/span><\/sub><\/span>?<\/b><\/span><\/span><\/span><\/p>\n

\u00a0<\/span><\/p>\n

04-(UEG-GO)<\/b><\/span><\/span><\/span> Linhas de for\u00e7a s\u00e3o linhas tangentes ao vetor campo el\u00e9trico em cada um de seus pontos, sendo essas linhas de for\u00e7a orientadas no sentido do vetor campo e perpendiculares \u00e0s superf\u00edcies eq\u00fcipotenciais. Das figuras a seguir, qual(is) pode(m) representar as linhas de for\u00e7a de um campo el\u00e9trico produzido por cargas el\u00e9tricas estacion\u00e1rias?<\/b><\/span><\/span><\/span><\/p>\n

\"\"<\/p>\n

a) Apenas a figura I.\u00a0\u00a0\u00a0\u00a0\u00a0<\/b><\/span><\/span><\/span><\/p>\n

b) As figuras I e IV.\u00a0\u00a0\u00a0\u00a0\u00a0<\/b><\/span><\/span><\/span><\/p>\n

c) As figuras I, II e IV.\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0<\/b><\/span><\/span><\/span><\/p>\n

d) As figuras I, III e IV.\u00a0\u00a0\u00a0\u00a0\u00a0<\/b><\/span><\/span><\/span><\/p>\n

e) Todas as figuras.<\/b><\/span><\/span><\/span><\/p>\n

\u00a0<\/span><\/p>\n

05-(UEG-GO) <\/b><\/span><\/span><\/span>A figura a seguir representa as linhas de campo el\u00e9trico de duas cargas puntiformes.<\/b><\/span><\/span><\/span><\/p>\n

\"\"<\/p>\n

Com base na an\u00e1lise da figura, responda aos itens a seguir.<\/b><\/span><\/span><\/span><\/p>\n

a) Quais s\u00e3o os sinais das cargas A e B? Justifique.<\/b><\/span><\/span><\/span><\/p>\n

b) Crie uma rela\u00e7\u00e3o entre os m\u00f3dulos das cargas A e B. Justifique.<\/b><\/span><\/span><\/span><\/p>\n

c) Seria poss\u00edvel \u00e0s linhas de campo el\u00e9trico se cruzarem? Justifique.<\/b><\/span><\/span><\/span><\/p>\n

\u00a0<\/span><\/p>\n

06-(FUVEST-SP)<\/b><\/span><\/span><\/span> Tr\u00eas grandes placas P<\/b><\/span><\/span><\/span>1<\/b><\/span><\/span><\/sub><\/span>, P<\/b><\/span><\/span><\/span>2<\/b><\/span><\/span><\/sub><\/span>\u00a0<\/b><\/span><\/span><\/span>e P<\/b><\/span><\/span><\/span>3<\/b><\/span><\/span><\/sub><\/span>, com, respectivamente, cargas +Q, -Q e +2Q, geram campos el\u00e9tricos uniformes em certas regi\u00f5es do espa\u00e7o. A figura 1 abaixo mostra intensidade, dire\u00e7\u00e3o e sentido dos campos criados pelas respectivas placas P<\/b><\/span><\/span><\/span>1<\/b><\/span><\/span><\/sub><\/span>, P<\/b><\/span><\/span><\/span>2<\/b><\/span><\/span><\/sub><\/span>\u00a0<\/b><\/span><\/span><\/span>e P<\/b><\/span><\/span><\/span>3<\/b><\/span><\/span><\/sub><\/span>, quando vistas de perfil. Colocando-se as placas pr\u00f3ximas, separadas pela dist\u00e2ncia D indicada, o campo el\u00e9trico resultante, gerado pelas tr\u00eas placas em conjunto, \u00e9 representado por<\/b><\/span><\/span><\/span><\/p>\n

\"\"<\/p>\n

Nota: onde n\u00e3o h\u00e1 indica\u00e7\u00e3o, o campo el\u00e9trico \u00e9 nulo<\/b><\/span><\/span><\/span><\/p>\n

\u00a0<\/span><\/p>\n

07-(UEM-PR) <\/b><\/span><\/span><\/span>Considere um corpo met\u00e1lico descarregado, AB, colocado em repouso em um campo el\u00e9trico cujas linhas de for\u00e7a s\u00e3o mostradas na figura a seguir. Assinale o que for correto.<\/b><\/span><\/span><\/span><\/p>\n

\"\"<\/p>\n

(01) Em virtude da indu\u00e7\u00e3o eletrost\u00e1tica no corpo met\u00e1lico, a sua extremidade A ficar\u00e1 eletrizada negativamente e a sua extremidade B ficar\u00e1 eletrizada positivamente.<\/b><\/span><\/span><\/span><\/p>\n

(02) Nas proximidades da regi\u00e3o A do corpo met\u00e1lico, a intensidade do campo el\u00e9trico externo \u00e9 maior do que nas proximidades da regi\u00e3o B.<\/b><\/span><\/span><\/span><\/p>\n

(04) A for\u00e7a el\u00e9trica F<\/b><\/span><\/span><\/span>A<\/b><\/span><\/span><\/sub><\/span>, que age sobre a extremidade A do corpo met\u00e1lico, aponta para a esquerda da figura.<\/b><\/span><\/span><\/span><\/p>\n

(08) A for\u00e7a el\u00e9trica F<\/b><\/span><\/span><\/span>B<\/b><\/span><\/span><\/sub><\/span>, que age sobre a extremidade B do corpo met\u00e1lico, aponta para a direita da figura.<\/b><\/span><\/span><\/span><\/p>\n

(16) Sob a a\u00e7\u00e3o das for\u00e7as F<\/b><\/span><\/span><\/span>A<\/b><\/span><\/span><\/sub><\/span>\u00a0<\/b><\/span><\/span><\/span>e F<\/b><\/span><\/span><\/span>B<\/b><\/span><\/span><\/sub><\/span>, o corpo met\u00e1lico tender\u00e1 a se deslocar para a esquerda da figura.<\/b><\/span><\/span><\/span><\/p>\n

(32) Se as linhas de for\u00e7a do campo el\u00e9trico representado na figura fossem paralelas e igualmente espa\u00e7adas, F<\/b><\/span><\/span><\/span>A<\/b><\/span><\/span><\/sub><\/span>\u00a0<\/b><\/span><\/span><\/span>apontaria para a direita e F<\/b><\/span><\/span><\/span>B<\/b><\/span><\/span><\/sub><\/span>\u00a0<\/b><\/span><\/span><\/span>apontaria para a esquerda.<\/b><\/span><\/span><\/span><\/p>\n

(64) Se as linhas de for\u00e7a do campo el\u00e9trico representado na figura fossem paralelas e igualmente espa\u00e7adas, o corpo permaneceria em repouso.<\/b><\/span><\/span><\/span><\/p>\n

\u00a0<\/span><\/p>\n

08-(PUC-MG)<\/b><\/span><\/span><\/span> As linhas de for\u00e7a de um campo el\u00e9trico s\u00e3o um modo conveniente de visualizar o campo el\u00e9trico e indicam a dire\u00e7\u00e3o do campo em qualquer ponto. Leia as op\u00e7\u00f5es abaixo e assinale a afirmativa INCORRETA.<\/b><\/span><\/span><\/span><\/p>\n

a) O n\u00famero de linhas que saem ou que entram numa carga puntiforme \u00e9 proporcional ao valor da carga el\u00e9trica.<\/b><\/span><\/span><\/span><\/p>\n

b) As linhas de for\u00e7a saem da carga negativa e entram na carga positiva.<\/b><\/span><\/span><\/span><\/p>\n

c) As linhas de for\u00e7a saem da carga positiva e entram na carga negativa.<\/b><\/span><\/span><\/span><\/p>\n

d) O n\u00famero de linhas por unidade de \u00e1rea perpendicular \u00e0s linhas \u00e9 proporcional \u00e0 intensidade do campo.<\/b><\/span><\/span><\/span><\/p>\n

\u00a0<\/span><\/p>\n

09-(PUC-RS)<\/b><\/span><\/span><\/span> A figura a seguir representa um campo el\u00e9trico n\u00e3o uniforme, uma carga de prova q<\/b><\/span><\/span><\/span>+<\/b><\/span><\/span><\/sub><\/span>\u00a0<\/b><\/span><\/span><\/span>e cinco pontos<\/b><\/span><\/span><\/span><\/p>\n

A figura a seguir representa um campo el\u00e9trico n\u00e3o uniforme, uma carga de prova q<\/b><\/span><\/span><\/span>+<\/b><\/span><\/span><\/sub><\/span>\u00a0<\/b><\/span><\/span><\/span>e cinco pontos quaisquer no interior do campo.<\/b><\/span><\/span><\/span><\/p>\n

\"\"<\/p>\n

O campo el\u00e9trico \u00e9 mais intenso no ponto<\/b><\/span><\/span><\/span><\/p>\n

\"\"<\/p>\n

10-(UFV-MG) <\/b><\/span><\/span><\/span>A figura a seguir representa a configura\u00e7\u00e3o de linhas de campo el\u00e9trico produzida por<\/b><\/span><\/span><\/span><\/p>\n

\"\"<\/p>\n

\u00a0tr\u00eas cargas puntuais,todas com o mesmo m\u00f3dulo Q. Os sinais das cargas A, B e C s\u00e3o, respectivamente:<\/b><\/span><\/span><\/span><\/p>\n

a) negativo, positivo e negativo.\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0<\/b><\/span><\/span><\/span><\/p>\n

b) negativo, negativo e positivo.\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0<\/b><\/span><\/span><\/span><\/p>\n

c) positivo, positivo e positivo.<\/b><\/span><\/span><\/span><\/p>\n

d) negativo, negativo e negativo.\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0<\/b><\/span><\/span><\/span><\/p>\n

e) positivo, negativo e positivo.<\/b><\/span><\/span><\/span><\/p>\n

\u00a0<\/span><\/p>\n

\u00a0<\/span><\/p>\n

11-(UFF-RJ)<\/b><\/span><\/span><\/span> Est\u00e3o representadas, a seguir, as linhas de for\u00e7a do campo el\u00e9trico criado por um dipolo.<\/b><\/span><\/span><\/span><\/p>\n

\"\"<\/p>\n

Considerando-se o dipolo, afirma-se:<\/b><\/span><\/span><\/span><\/p>\n

1. A representa\u00e7\u00e3o das linhas de campo el\u00e9trico resulta da superposi\u00e7\u00e3o dos campos criados pelas cargas puntiformes.<\/b><\/span><\/span><\/span><\/p>\n

II. O dipolo \u00e9 composto por duas cargas de mesma intensidade e sinais contr\u00e1rios.<\/b><\/span><\/span><\/span><\/p>\n

III. O campo el\u00e9trico criado por uma das cargas modifica o campo el\u00e9trico criado pela outra.<\/b><\/span><\/span><\/span><\/p>\n

Com rela\u00e7\u00e3o a estas afirmativas, conclui-se que:<\/b><\/span><\/span><\/span><\/p>\n

a) apenas a I \u00e9 correta. \u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0<\/b><\/span><\/span><\/span><\/p>\n

b) apenas a lI \u00e9 correta. \u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0<\/b><\/span><\/span><\/span><\/p>\n

c) apenas a III \u00e9 correta. \u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0<\/b><\/span><\/span><\/span><\/p>\n

d) apenas a I e a II s\u00e3o corretas.\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0<\/b><\/span><\/span><\/span><\/p>\n

e) apenas a lI e a III s\u00e3o corretas.<\/b><\/span><\/span><\/span><\/p>\n

\u00a0<\/span><\/p>\n

12-(PUC-PR)<\/b><\/span><\/span><\/span> As linhas de for\u00e7a foram idealizadas pelo f\u00edsico ingl\u00eas Michael Faraday com o objetivo de visualizar o campo el\u00e9trico numa regi\u00e3o do espa\u00e7o. Em cada ponto de uma linha de for\u00e7a, a dire\u00e7\u00e3o do campo el\u00e9trico \u00e9 tangente \u00e0 linha. Qual das afirma\u00e7\u00f5es abaixo N\u00c3O cor responde a uma propriedade das linhas de for\u00e7a?<\/b><\/span><\/span><\/span><\/p>\n

a) As linhas de for\u00e7a de um campo el\u00e9trico uniforme s\u00e3o paralelas e eq\u00fcidistantes entre si.<\/b><\/span><\/span><\/span><\/p>\n

b) Para uma carga puntiforme positiva, as linhas de for\u00e7a apontam \u201cpara fora\u201d da carga.<\/b><\/span><\/span><\/span><\/p>\n

c) As linhas de for\u00e7a \u201cconvergem\u201d para cargas puntiformes negativas.<\/b><\/span><\/span><\/span><\/p>\n

d) Nas vizinhan\u00e7as da superf\u00edcie de um condutor isolado e carregado, as linhas de for\u00e7a s\u00e3o perpendiculares \u00e0 superf\u00edcie.<\/b><\/span><\/span><\/span><\/p>\n

e) As linhas de for\u00e7a do campo el\u00e9trico s\u00e3o sempre fechadas.<\/b><\/span><\/span><\/span><\/p>\n

\u00a0<\/span><\/p>\n

13-(FURG-RS)<\/b><\/span><\/span><\/span> A Figura mostra as linhas de for\u00e7a do campo el\u00e9trico. As afirmativas referem-se a esta figura.<\/b><\/span><\/span><\/span><\/p>\n

\"\"<\/p>\n

I. A intensidade do campo el\u00e9trico E na regi\u00e3o A \u00e9 maior do que na regi\u00e3o C<\/b><\/span><\/span><\/span><\/p>\n

II. Uma carga negativa colocada nas regi\u00f5es A ou C sofre uma for\u00e7a para a esquerda.<\/b><\/span><\/span><\/span><\/p>\n

III. Uma carga positiva colocada nas regi\u00f5es A ou C sofre uma for\u00e7a para a direita.<\/b><\/span><\/span><\/span><\/p>\n

Est\u00e1(\u00e3o) correta(s):<\/b><\/span><\/span><\/span><\/p>\n

\"\"<\/p>\n

14-(UFMG-MG)<\/b><\/span><\/span><\/span> A figura mostra, esquematicamente, as partes principais de uma impressora a jato de tinta.<\/b><\/span><\/span><\/span><\/p>\n

\"\"<\/p>\n

Durante o processo de impress\u00e3o, um campo el\u00e9trico \u00e9 aplicado de modo a desviar as gotas eletrizadas. Dessa maneira, as gotas incidem exatamente no lugar programado da folha de papel onde se formar\u00e1, por exemplo, parte de uma letra. Considere que as gotas s\u00e3o eletrizadas negativamente. Para que elas atinjam o ponto P da figura, o vetor campo el\u00e9trico entre as placas defletoras \u00e9 melhor representado por:<\/b><\/span><\/span><\/span><\/p>\n

\"\"<\/p>\n

\u00a0<\/span><\/p>\n

15-(UNIFEI-MG)<\/b><\/span><\/span><\/span> As figuras abaixo mostram as linhas de for\u00e7a do campo eletrost\u00e1tico criado por um<\/b><\/span><\/span><\/span><\/p>\n

\"\"<\/p>\n

\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0I\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0II<\/b><\/span><\/span><\/span><\/p>\n

sistema de duas cargas puntiformes. Quais das respostas abaixo \u00e9 verdadeira?<\/b><\/span><\/span><\/span><\/p>\n

a) Em II temos duas cargas negativas de mesmo m\u00f3dulo e em I temos duas cargas positivas de mesmo m\u00f3dulo.<\/b><\/span><\/span><\/span><\/p>\n

b) Em II e em I as duas cargas apresentam sinais opostos. Nada podemos dizer sobre os m\u00f3dulos das cargas.<\/b><\/span><\/span><\/span><\/p>\n

c) Em II temos duas cargas positivas de mesmo m\u00f3dulo e em I temos duas cargas de m\u00f3dulos diferentes e sinais opostos.<\/b><\/span><\/span><\/span><\/p>\n

d) As cargas em I e II apresentam m\u00f3dulos diferentes. Nada podemos dizer sobre o sinal das cargas.<\/b><\/span><\/span><\/span><\/p>\n

e) Todas as respostas est\u00e3o erradas.<\/b><\/span><\/span><\/span><\/p>\n

\u00a0<\/span><\/p>\n

16-(UFRGS)<\/b><\/span><\/span><\/span> Uma carga de \u201310<\/b><\/span><\/span><\/span>-6<\/b><\/span><\/span><\/sup><\/span>\u00a0<\/b><\/span><\/span><\/span>C est\u00e1 uniformemente distribu\u00edda sobre a superf\u00edcie terrestre.<\/b><\/span><\/span><\/span><\/p>\n

\"\"<\/p>\n

Considerando-se que o potencial el\u00e9trico criado por essa carga \u00e9 nulo a uma dist\u00e2ncia infinita, qual ser\u00e1 aproximadamente o valor desse potencial el\u00e9trico sobre a superf\u00edcie da Lua?<\/b><\/span><\/span><\/span><\/p>\n

Dados: D<\/b><\/span><\/span><\/span>Terra-Lua<\/b><\/span><\/span><\/sub><\/span>\u00a0<\/b><\/span><\/span><\/span>=3,8.10<\/b><\/span><\/span><\/span>8<\/b><\/span><\/span><\/sup><\/span>m; k = 9.10<\/b><\/span><\/span><\/span>9<\/b><\/span><\/span><\/sup><\/span>Nm<\/b><\/span><\/span><\/span>2<\/b><\/span><\/span><\/sup><\/span>\/C<\/b><\/span><\/span><\/span>2<\/b><\/span><\/span><\/sup><\/span><\/p>\n

\"\"<\/p>\n

17-(PUC-RS)<\/b><\/span><\/span><\/span> Uma carga de 2,0 . 10<\/b><\/span><\/span><\/span>-7<\/b><\/span><\/span><\/sup><\/span>C<\/b><\/span><\/span><\/span>\u00a0<\/b><\/span><\/span><\/span>encontra-se isolada, no v\u00e1cuo, distante 6,0cm de um ponto P. Dado: K<\/b><\/span><\/span><\/span>0<\/b><\/span><\/span><\/sub><\/span>\u00a0<\/b><\/span><\/span><\/span>= 9,0 . 10<\/b><\/span><\/span><\/span>9<\/b><\/span><\/span><\/sup><\/span>\u00a0<\/b><\/span><\/span><\/span>unidades SI<\/b><\/span><\/span><\/span>\u00a0<\/b><\/span><\/span><\/span>Qual a proposi\u00e7\u00e3o correta?<\/b><\/span><\/span><\/span><\/p>\n

\u00a0a) O vetor campo el\u00e9trico no ponto P est\u00e1 voltado para a carga.<\/b><\/span><\/span><\/span><\/p>\n

\u00a0b) O campo el\u00e9trico no ponto P \u00e9 nulo porque n\u00e3o h\u00e1 nenhuma carga el\u00e9trica em P.<\/b><\/span><\/span><\/span><\/p>\n

\u00a0c) O potencial el\u00e9trico no ponto P \u00e9 positivo e vale 3,0<\/b><\/span><\/span><\/span>\u00a0<\/b><\/span><\/span><\/span>.<\/b><\/span><\/span><\/span>\u00a0<\/b><\/span><\/span><\/span>10<\/b><\/span><\/span><\/span>4<\/b><\/span><\/span><\/sup><\/span>V.<\/b><\/span><\/span><\/span><\/p>\n

\u00a0d) O potencial el\u00e9trico no ponto P \u00e9 negativo e vale -5,0<\/b><\/span><\/span><\/span>\u00a0<\/b><\/span><\/span><\/span>.<\/b><\/span><\/span><\/span>\u00a0<\/b><\/span><\/span><\/span>10<\/b><\/span><\/span><\/span>4<\/b><\/span><\/span><\/sup><\/span>V.<\/b><\/span><\/span><\/span><\/p>\n

\u00a0e) Em P s\u00e3o nulos o campo el\u00e9trico e o potencial, pois a\u00ed n\u00e3o existe carga el\u00e9trica.<\/b><\/span><\/span><\/span><\/p>\n

\u00a0<\/span><\/p>\n

18-(PUC-SP)<\/b><\/span><\/span><\/span> Dois pontos A e B tem potenciais, em rela\u00e7\u00e3o a um n\u00edvel no infinito, iguais a 150V e 100V, respectivamente. Supondo que se passe a medir os potenciais em rela\u00e7\u00e3o a B, o novo potencial de A ser\u00e1, em volts:<\/b><\/span><\/span><\/span><\/p>\n

\"\"<\/p>\n

19-(CESGRANRIO-RJ)<\/b><\/span><\/span><\/span> Nas figuras, tr\u00eas cargas positivas e pontuais q s\u00e3o localizadas sobre a circunfer\u00eancia de um c\u00edrculo de raio R de tr\u00eas maneiras diferentes. As afirma\u00e7\u00f5es seguintes se referem ao potencial eletrost\u00e1tico em O, centro da circunfer\u00eancia (o zero dos potenciais est\u00e1 no infinito):
\nI. O potencial em O nas figuras 1 e 3 \u00e9 dirigido para baixo.
\nII. O potencial em O tem o mesmo valor (n\u00e3o-nulo) nos tr\u00eas casos.
\nIII. O potencial em O na figura 2 \u00e9 nulo.<\/b><\/span><\/span><\/span><\/p>\n

\"\"<\/p>\n

Est\u00e1(\u00e3o) certa(s) a(s) afirma\u00e7\u00e3o(\u00f5es):<\/b><\/span><\/span><\/span><\/p>\n

a) I e II somente.\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0<\/b><\/span><\/span><\/span><\/p>\n

b) II somente.\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0<\/b><\/span><\/span><\/span><\/p>\n

c) III somente.\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0<\/b><\/span><\/span><\/span><\/p>\n

d) I somente.\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0<\/b><\/span><\/span><\/span><\/p>\n

e) I e III somente.<\/b><\/span><\/span><\/span><\/p>\n

\u00a0<\/span><\/p>\n

20-(UECE-CE)<\/b><\/span><\/span><\/span> “n” pr\u00f3tons, cada um de carga q, foram distribu\u00eddos aleatoriamente ao longo de um arco de c\u00edrculo de 60\u00b0 e raio r, conforme ilustra a figura.<\/b><\/span><\/span><\/span><\/p>\n

\"\"<\/p>\n

conforme ilustra a\u00a0 figura. Considerando k = 1\/(4\u03c0\u03b5<\/b><\/span><\/span><\/span>o<\/b><\/span><\/span><\/sub><\/span>) e o potencial de refer\u00eancia no infinito igual a zero, assinale a alternativa que cont\u00e9m o valor do potencial el\u00e9trico no ponto O devido a esses pr\u00f3tons.<\/b><\/span><\/span><\/span><\/p>\n

\"\"<\/p>\n

\u00a0<\/span><\/p>\n

21-(FMVASSOURAS-MG)<\/b><\/span><\/span><\/span> Tr\u00eas v\u00e9rtices n\u00e3o consecutivos de um hex\u00e1gono regular s\u00e3o ocupados por cargas\u00a0el\u00e9tricas pontuais.<\/b><\/span><\/span><\/span><\/p>\n

\"\"<\/p>\n

Duas destas cargas t\u00eam o mesmo valor<\/b><\/span><\/span><\/span>\u00a0<\/b><\/span><\/span><\/span>q<\/b><\/span><\/span><\/span>\u00a0<\/b><\/span><\/span><\/span>e a terceira vale<\/b><\/span><\/span><\/span>\u00a0<\/b><\/span><\/span><\/span>Q. Sendo nulo o potencial el\u00e9trico no v\u00e9rtice A n\u00e3o ocupado por carga, \u00e9 correto afirmar que:\u00a0<\/b><\/span><\/span><\/span><\/p>\n

\u00a0a) Q = -q \u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0<\/b><\/span><\/span><\/span><\/p>\n

b) Q = -2q\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 \u00a0<\/b><\/span><\/span><\/span><\/p>\n

c) Q = -3q \u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0<\/b><\/span><\/span><\/span><\/p>\n

d) Q = -4q\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0<\/b><\/span><\/span><\/span><\/p>\n

e) Q = -6q<\/b><\/span><\/span><\/span><\/p>\n

\u00a0<\/span><\/p>\n

22-(UNICAMP-SP)<\/b><\/span><\/span><\/span> Considere uma mol\u00e9cula diat\u00f4mica i\u00f4nica. Um \u00e1tomo tem carga q=1,6.10<\/b><\/span><\/span><\/span>-19<\/b><\/span><\/span><\/sup><\/span>C, e o<\/b><\/span><\/span><\/span><\/p>\n

\"\"<\/p>\n

\u00a0outro tem carga oposta. A distancia interat\u00f4mica de equil\u00edbrio \u00e9 2,0.10<\/b><\/span><\/span><\/span>-10<\/b><\/span><\/span><\/sup><\/span>m. No Sistema Internacional K \u00e9 igual a 9,0.10<\/b><\/span><\/span><\/span>9<\/b><\/span><\/span><\/sup><\/span>. Na dist\u00e2ncia de equil\u00edbrio, a for\u00e7a de atra\u00e7\u00e3o entre as cargas \u00e9 anulada por outras for\u00e7as internas da mol\u00e9cula.<\/b><\/span><\/span><\/span><\/p>\n

a) Qual \u00e9 a resultante das outras for\u00e7as internas\u00a0 que anula a for\u00e7a de atra\u00e7\u00e3o entre as cargas.<\/b><\/span><\/span><\/span><\/p>\n

b) Considerando que, para dist\u00e2ncias interat\u00f4micas maiores que a dist\u00e2ncia de equil\u00edbrio, as outras for\u00e7as internas s\u00e3o desprez\u00edveis, determine a energia necess\u00e1ria para separar completamente as duas cargas, isto \u00e9, para dissociar a mol\u00e9cula em dois \u00edons.<\/b><\/span><\/span><\/span><\/p>\n

\u00a0<\/span><\/p>\n

23-(FUVEST-SP)<\/b><\/span><\/span><\/span> Quando se aproximam duas part\u00edculas que se repelem, a energia potencial das duas part\u00edculas: \u00a0<\/b><\/span><\/span><\/span><\/p>\n

a) aumenta \u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0<\/b><\/span><\/span><\/span><\/p>\n

b) diminui\u00a0 \u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0<\/b><\/span><\/span><\/span><\/p>\n

c) fica constante \u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0<\/b><\/span><\/span><\/span><\/p>\n

d) diminui e, em seguida, aumenta;<\/b><\/span><\/span><\/span><\/p>\n

e) aumenta e, em seguida, diminui. \u00a0<\/b><\/span><\/span><\/span><\/p>\n

\u00a0<\/span><\/p>\n

24-(UFLavras-MG)<\/b><\/span><\/span><\/span> O diagrama potencial el\u00e9trico versus dist\u00e2ncia de uma carga el\u00e9trica puntiforme Q no v\u00e1cuo \u00e9 mostrado abaixo. Considere a constante eletrost\u00e1tica do v\u00e1cuo K<\/b><\/span><\/span><\/span>o<\/b><\/span><\/span><\/sub><\/span>=9.10<\/b><\/span><\/span><\/span>9<\/b><\/span><\/span><\/sup><\/span>N.m<\/b><\/span><\/span><\/span>2<\/b><\/span><\/span><\/sup><\/span>\/C<\/b><\/span><\/span><\/span>2<\/b><\/span><\/span><\/sup><\/span>.<\/b><\/span><\/span><\/span><\/p>\n

\"\"<\/p>\n

Pode-se afirmar que o valor de Q \u00e9:<\/b><\/span><\/span><\/span><\/p>\n

a) +3,0.10<\/b><\/span><\/span><\/span>-12<\/b><\/span><\/span><\/sup><\/span>C\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0<\/b><\/span><\/span><\/span><\/p>\n

b) +0,1.10<\/b><\/span><\/span><\/span>-12<\/b><\/span><\/span><\/sup><\/span>C\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0<\/b><\/span><\/span><\/span><\/p>\n

c) +3,0.10<\/b><\/span><\/span><\/span>-9<\/b><\/span><\/span><\/sup><\/span>C\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0<\/b><\/span><\/span><\/span><\/p>\n

d) +0,1.10<\/b><\/span><\/span><\/span>-9<\/b><\/span><\/span><\/sup><\/span>C\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0<\/b><\/span><\/span><\/span><\/p>\n

e) -3,0.10<\/b><\/span><\/span><\/span>-12<\/b><\/span><\/span><\/sup><\/span>C<\/b><\/span><\/span><\/span><\/p>\n

\u00a0<\/span><\/p>\n

25-(UNICAMP)<\/b><\/span><\/span><\/span> Uma carga de -2,0.10<\/b><\/span><\/span><\/span>-9<\/b><\/span><\/span><\/sup><\/span>C<\/b><\/span><\/span><\/span>\u00a0<\/b><\/span><\/span><\/span>est\u00e1 na origem de um eixo X. A diferen\u00e7a de potencial<\/b><\/span><\/span><\/span><\/p>\n

\"\"<\/p>\n

entre\u00a0x<\/b><\/span><\/span><\/span>1<\/b><\/span><\/span><\/sub><\/span>\u00a0<\/b><\/span><\/span><\/span>= 1,0m e\u00a0x<\/b><\/span><\/span><\/span>2<\/b><\/span><\/span><\/sub><\/span>\u00a0<\/b><\/span><\/span><\/span>= 2,0m (em V) \u00e9:<\/b><\/span><\/span><\/span><\/p>\n

\"\"<\/p>\n

\u00a0<\/span><\/p>\n

26-(PUC-MG)<\/b><\/span><\/span><\/span> A diferen\u00e7a de energia potencial el\u00e9trica existente entre duas cargas puntiformes separadas por uma certa dist\u00e2ncia ficar\u00e1 inalterada se:<\/b><\/span><\/span><\/span><\/p>\n

a) as cargas forem mantidas e a dist\u00e2ncia dividida por dois. \u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0<\/b><\/span><\/span><\/span><\/p>\n

b) cada carga for dobrada e a dist\u00e2ncia tamb\u00e9m.<\/b><\/span><\/span><\/span><\/p>\n

c) uma das cargas for dobrada e a dist\u00e2ncia multiplicada por quatro. \u00a0\u00a0\u00a0<\/b><\/span><\/span><\/span><\/p>\n

d)cada carga for quadruplicada e dist\u00e2ncia dividida por dois. \u00a0\u00a0\u00a0\u00a0\u00a0\u00a0<\/b><\/span><\/span><\/span><\/p>\n

e) cada carga for dobrada e a dist\u00e2ncia multiplicada por quatro.<\/b><\/span><\/span><\/span><\/p>\n

\u00a0<\/span><\/p>\n

27-(UNESP-SP)<\/b><\/span><\/span><\/span> Na configura\u00e7\u00e3o de cargas da figura, qual \u00e9 a express\u00e3o que representa o potencial el\u00e9trico no ponto P?<\/b><\/span><\/span><\/span><\/p>\n

\"\"<\/p>\n

(K = constante eletrost\u00e1tica do v\u00e1cuo)<\/b><\/span><\/span><\/span><\/p>\n

\"\"<\/p>\n

28-(PUC-RJ)<\/b><\/span><\/span><\/span> Uma carga positiva puntiforme \u00e9 liberada a partir do repouso em uma regi\u00e3o do espa\u00e7o onde o campo el\u00e9trico \u00e9 uniforme e constante. Se a part\u00edcula se move na mesma dire\u00e7\u00e3o e sentido do campo el\u00e9trico, a energia potencial eletrost\u00e1tica do sistema<\/b><\/span><\/span><\/span><\/p>\n

a) aumenta e a energia cin\u00e9tica da part\u00edcula aumenta.\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0<\/b><\/span><\/span><\/span><\/p>\n

b) diminui e a energia cin\u00e9tica da part\u00edcula diminui.<\/b><\/span><\/span><\/span><\/p>\n

c) e a energia cin\u00e9tica da part\u00edcula permanecem constantes.\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0<\/b><\/span><\/span><\/span><\/p>\n

d) aumenta e a energia cin\u00e9tica da part\u00edcula diminui.<\/b><\/span><\/span><\/span><\/p>\n

e) diminui e a energia cin\u00e9tica da part\u00edcula aumenta.<\/b><\/span><\/span><\/span><\/p>\n

\u00a0<\/span><\/p>\n

29- (UFRS-RS)<\/b><\/span><\/span><\/span> Duas cargas el\u00e9tricas puntiformes, de mesmo m\u00f3dulo e sinais contr\u00e1rios, est\u00e3o<\/b><\/span><\/span><\/span><\/p>\n

\"\"<\/p>\n

fixas nos pontos X e Y representados na figura. Em que pontos indicados na figura a diferen\u00e7a de potencial gerada pelas cargas \u00e9 nula?<\/b><\/span><\/span><\/span><\/p>\n

\"\"<\/p>\n

30-(PUC-RS)<\/b><\/span><\/span><\/span> Uma carga el\u00e9trica puntual Q est\u00e1 colocada em um ponto P como mostra a figura.<\/b><\/span><\/span><\/span><\/p>\n

\"\"<\/p>\n

Os pontos que se encontram no mesmo potencial el\u00e9trico s\u00e3o, respectivamente,<\/b><\/span><\/span><\/span><\/p>\n

\"\"<\/p>\n

\u00a0<\/span><\/p>\n

31-(PUC-MG)<\/b><\/span><\/span><\/span> As configura\u00e7\u00f5es A, B e C, que representam quatro cargas de mesmo valor, situadas nos v\u00e9rtices de um quadrado, conforme a figura abaixo, ser\u00e3o utilizadas nas quest\u00f5es_31 e 32.<\/b><\/span><\/span><\/span><\/p>\n

\"\"<\/p>\n

\u00a0<\/span><\/p>\n

Escolha a op\u00e7\u00e3o que contenha a configura\u00e7\u00e3o ou configura\u00e7\u00f5es em que o campo el\u00e9trico no centro do quadrado tenha o maior valor:<\/b><\/span><\/span><\/span><\/p>\n

\"\"<\/p>\n

32-(PUC-MG)<\/b><\/span><\/span><\/span> Escolha a op\u00e7\u00e3o que contenha a configura\u00e7\u00e3o ou configura\u00e7\u00f5es em que o potencial el\u00e9trico no centro do quadrado tenha o menor valor:<\/b><\/span><\/span><\/span><\/p>\n

a) A \u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0<\/b><\/span><\/span><\/span><\/p>\n

b) B \u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0<\/b><\/span><\/span><\/span><\/p>\n

c) C \u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0<\/b><\/span><\/span><\/span><\/p>\n

d) B e C \u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0<\/b><\/span><\/span><\/span><\/p>\n

e) A, B e C<\/b><\/span><\/span><\/span><\/p>\n

33-(UESB-BA)<\/b><\/span><\/span><\/span> Uma carga el\u00e9trica q > 0, abandonada em repouso na regi\u00e3o de um campo el\u00e9trico<\/b><\/span><\/span><\/span><\/p>\n

\"\"<\/p>\n

uniforme<\/b><\/span><\/span><\/span>\u00a0\"\"<\/b><\/span><\/span><\/span>, ir\u00e1 se movimentar:<\/b><\/span><\/span><\/span><\/p>\n

(01) em sentido contr\u00e1rio \u00e0 orienta\u00e7\u00e3o de<\/b><\/span><\/span><\/span>\u00a0\"\"<\/b><\/span><\/span><\/span>.
\n(02) em trajet\u00f3ria retil\u00ednea, mantendo velocidade constante .
\n(03) sujeita a uma for\u00e7a el\u00e9trica de m\u00f3dulo igual a F=E\/q.
\n(04) aumentando a sua energia potencial el\u00e9trica.
\n(05) mantendo constante a sua energia mec\u00e2nica.<\/b><\/span><\/span><\/span><\/p>\n

\u00a0<\/span><\/p>\n

34-(UFRS-RS)<\/b><\/span><\/span><\/span> A figura a seguir representa duas cargas el\u00e9tricas puntiformes, mantidas fixas em suas posi\u00e7\u00f5es, de valores + 2q e – q, sendo q o m\u00f3dulo de uma carga de refer\u00eancia.<\/b><\/span><\/span><\/span><\/p>\n

\"\"<\/p>\n

Considerando-se zero o potencial el\u00e9trico no infinito, \u00e9 correto afirmar que o potencial el\u00e9trico criado pelas duas cargas ser\u00e1 zero tamb\u00e9m nos pontos<\/b><\/span><\/span><\/span><\/p>\n

\"\"<\/p>\n

\u00a0<\/span><\/p>\n

35-(UFCE)<\/b><\/span><\/span><\/span> Duas cargas puntiformes de valores Q e -3Q est\u00e3o separadas por uma distancia de 104 cm, conforme a figura.<\/b><\/span><\/span><\/span><\/p>\n

\"\"<\/p>\n

\u00a0O ponto A e pontos infinitamente distantes das cargas t\u00eam potencial nulo. Qual \u00e9, em cent\u00edmetros, a distancia entre a carga -3Q e o ponto A.<\/b><\/span><\/span><\/span><\/p>\n

\"\"<\/p>\n

36-(FUVEST-SP)<\/b><\/span><\/span><\/span> Um sistema formado por tr\u00eas cargas puntiformes iguais, colocadas em repouso nos v\u00e9rtices de um tri\u00e2ngulo<\/b><\/span><\/span><\/span><\/p>\n

eq\u00fcil\u00e1tero, tem energia potencial eletrost\u00e1tica igual a U. Substitui-se uma das cargas por outra, na mesma posi\u00e7\u00e3o, mas com o dobro do valor. A energia potencial eletrost\u00e1tica do novo sistema ser\u00e1 igual a:<\/b><\/span><\/span><\/span><\/p>\n

\"\"
\n<\/b><\/span><\/span><\/span>37-(PUC-RJ)<\/b><\/span><\/span><\/span> Duas part\u00edculas de cargas q<\/b><\/span><\/span><\/span>1<\/b><\/span><\/span><\/sub><\/span>\u00a0<\/b><\/span><\/span><\/span>= 4.10<\/b><\/span><\/span><\/span>-5<\/b><\/span><\/span><\/sup><\/span>\u00a0<\/b><\/span><\/span><\/span>C<\/b><\/span><\/span><\/span>\u00a0<\/b><\/span><\/span><\/span>e q<\/b><\/span><\/span><\/span>2<\/b><\/span><\/span><\/sub><\/span>\u00a0<\/b><\/span><\/span><\/span>= 1.10<\/b><\/span><\/span><\/span>-5<\/b><\/span><\/span><\/sup><\/span>\u00a0<\/b><\/span><\/span><\/span>C est\u00e3o alinhadas no eixo x sendo a separa\u00e7\u00e3o entre elas de 6 m.<\/b><\/span><\/span><\/span><\/p>\n

\"\"<\/p>\n

Sabendo que q<\/b><\/span><\/span><\/span>1<\/b><\/span><\/span><\/sub><\/span>\u00a0<\/b><\/span><\/span><\/span>encontra-se na origem do sistema de coordenadas e considerando k = 9.10<\/b><\/span><\/span><\/span>9<\/b><\/span><\/span><\/sup><\/span>Nm<\/b><\/span><\/span><\/span>2<\/b><\/span><\/span><\/sup><\/span>\/C<\/b><\/span><\/span><\/span>2<\/b><\/span><\/span><\/sup><\/span>, determine:<\/b><\/span><\/span><\/span><\/p>\n

a) a posi\u00e7\u00e3o x, entre as cargas, onde o campo el\u00e9trico \u00e9 nulo;<\/b><\/span><\/span><\/span><\/p>\n

b) o potencial eletrost\u00e1tico no ponto x = 3 m;<\/b><\/span><\/span><\/span><\/p>\n

c) o m\u00f3dulo, a dire\u00e7\u00e3o e o sentido da acelera\u00e7\u00e3o, no caso de ser colocada uma part\u00edcula de carga q<\/b><\/span><\/span><\/span>3<\/b><\/span><\/span><\/sub><\/span>\u00a0<\/b><\/span><\/span><\/span>= – 1 . 10<\/b><\/span><\/span><\/span>-5<\/b><\/span><\/span><\/sup><\/span>\u00a0<\/b><\/span><\/span><\/span>C e<\/b><\/span><\/span><\/span><\/p>\n

massa m<\/b><\/span><\/span><\/span>3<\/b><\/span><\/span><\/sub><\/span>\u00a0<\/b><\/span><\/span><\/span>= 1,0 kg, no ponto do meio da dist\u00e2ncia entre q<\/b><\/span><\/span><\/span>1<\/b><\/span><\/span><\/sub><\/span>\u00a0<\/b><\/span><\/span><\/span>e q<\/b><\/span><\/span><\/span>2<\/b><\/span><\/span><\/sub><\/span>.<\/b><\/span><\/span><\/span><\/p>\n

\u00a0<\/span><\/p>\n

38-(MACKENZIE-SP)<\/b><\/span><\/span><\/span> Na determina\u00e7\u00e3o do valor de uma carga el\u00e9trica puntiforme, observamos que, em um determinado ponto do campo el\u00e9trico por ela gerado, o potencial el\u00e9trico \u00e9 de 18 kV e a intensidade do vetor campo el\u00e9trico \u00e9 9,0 kN\/C. Se o meio \u00e9 o v\u00e1cuo (k = 9.10<\/b><\/span><\/span><\/span>9<\/b><\/span><\/span><\/sup><\/span>\u00a0<\/b><\/span><\/span><\/span>N.m<\/b><\/span><\/span><\/span>2<\/b><\/span><\/span><\/sup><\/span>\/C<\/b><\/span><\/span><\/span>2<\/b><\/span><\/span><\/sup><\/span>), determine o valor dessa carga.<\/b><\/span><\/span><\/span><\/p>\n

\u00a0<\/span><\/p>\n

39-(UDESC-SC)<\/b><\/span><\/span><\/span> O gr\u00e1fico a seguir representa a varia\u00e7\u00e3o da energia potencial de uma carga el\u00e9trica de 10<\/b><\/span><\/span><\/span>-6<\/b><\/span><\/span><\/sup><\/span>\u00a0<\/b><\/span><\/span><\/span>C, no v\u00e1cuo, submetida apenas \u00e0 a\u00e7\u00e3o de um campo el\u00e9trico uniforme e paralelo ao eixo x. Em x = 0,0 cm, a energia cin\u00e9tica da carga \u00e9 nula.<\/b><\/span><\/span><\/span><\/p>\n

\"\"<\/p>\n

\u00a0Determine o potencial el\u00e9trico em x = 0,6 cm.<\/b><\/span><\/span><\/span><\/p>\n

\u00a0<\/span><\/p>\n

\u00a0<\/span><\/p>\n

40-(ITA-SP)<\/b><\/span><\/span><\/span>\u00a0 Tr\u00eas esferas condutoras, de raio a e carga Q, ocupam os v\u00e9rtices de um tri\u00e2ngulo equil\u00e1tero de lado b > a, conforme mostra a figura (1). Considere as figuras (2), (3) e (4), em que, respectivamente, cada uma das esferas se liga e desliga da Terra, uma de cada vez. Determine, nas situa\u00e7\u00f5es (2), (3) e (4), a carga das esferas Q<\/b><\/span><\/span><\/span>1<\/b><\/span><\/span><\/sub><\/span>, Q<\/b><\/span><\/span><\/span>2<\/b><\/span><\/span><\/sub><\/span>\u00a0<\/b><\/span><\/span><\/span>e Q<\/b><\/span><\/span><\/span>3<\/b><\/span><\/span><\/sub><\/span>, respectivamente, em fun\u00e7\u00e3o de a, b e Q.<\/b><\/span><\/span><\/span><\/p>\n

\"\"<\/p>\n

\u00a0<\/span><\/p>\n

41-(UFC)<\/b><\/span><\/span><\/span>\u00a0 Na figura a seguir, \u00e9 mostrada uma distribui\u00e7\u00e3o de tr\u00eas part\u00edculas carregadas (duas com carga positiva e uma com carga negativa) localizadas ao longo dos eixos perpendiculares de um dado sistema de refer\u00eancia. Todas as dist\u00e2ncias est\u00e3o em unidades arbitr\u00e1rias (u.a.). As cargas positivas, ambas iguais a q, est\u00e3o fixas nas coordenadas (x,y), iguais a (4,0) e (- 4,0). A carga negativa, igual a – q, est\u00e1 localizada, inicialmente em repouso, no ponto A, cujas coordenadas s\u00e3o (0,3). A acelera\u00e7\u00e3o da gravidade local \u00e9 constante (m\u00f3dulo g) e aponta no sentido negativo do eixo y do sistema de refer\u00eancia, que est\u00e1 na vertical. Todas as part\u00edculas possuem a mesma massa m. A constante eletrost\u00e1tica no meio em que as part\u00edculas carregadas est\u00e3o imersas \u00e9 K.<\/b><\/span><\/span><\/span><\/p>\n

\"\"<\/p>\n

Determine o m\u00f3dulo da velocidade com que a part\u00edcula com carga negativa chega ao ponto P, localizado pelas coordenadas (x,y) = (0,-3).<\/b><\/span><\/span><\/span>\u00a0<\/b><\/span><\/span><\/span>
\n<\/b><\/span><\/span><\/span><\/p>\n

42-(ENEM-MEC)<\/b><\/span><\/span><\/span> As c\u00e9lulas possuem potencial de membrana, que pode ser classificado em repouso ou a\u00e7\u00e3o, e \u00e9 uma estrat\u00e9gia eletrofisiol\u00f3gica interessante e simples do ponto de vista f\u00edsico. Essa caracter\u00edstica eletrofisiol\u00f3gica est\u00e1 presente na figura a seguir, que mostra um potencial de a\u00e7\u00e3o disparado por uma c\u00e9lula que comp\u00f5e as fibras de Purkinje, respons\u00e1veis por conduzir os impulsos el\u00e9tricos para o tecido card\u00edaco, possibilitando assim a contra\u00e7\u00e3o card\u00edaca. Observa-se que existem quatro fases envolvidas nesse potencial de a\u00e7\u00e3o, sendo denominadas fases 0, 1, 2 e 3.<\/b><\/span><\/span><\/span><\/p>\n

\"\"<\/p>\n

\u00a0\u00a0 O potencial de repouso dessa c\u00e9lula \u00e9 -100 mV, e quando ocorre influxo de \u00edons Na+ e Ca2+, a polaridade celular pode atingir valores de at\u00e9 +10 mV, o que se denomina despolariza\u00e7\u00e3o celular. A modifica\u00e7\u00e3o no potencial de repouso pode disparar um potencial de a\u00e7\u00e3o quando a voltagem da membrana atinge o limiar de disparo que est\u00e1 representado na figura pela linha pontilhada. Contudo, a c\u00e9lula n\u00e3o pode se manter despolarizada, pois isso acarretaria a morte celular. Assim, ocorre a repolariza\u00e7\u00e3o celular, <\/b><\/span><\/span><\/span>mecanismo<\/b><\/span><\/span><\/span> que reverte a despolariza\u00e7\u00e3o e retorna a c\u00e9lula ao potencial de repouso. Para tanto, h\u00e1 o efluxo celular de \u00edons K+.<\/b><\/span><\/span><\/span><\/p>\n

Qual das fases, presentes na figura, indica o processo de despolariza\u00e7\u00e3o e repolariza\u00e7\u00e3o celular, respectivamente?<\/b><\/span><\/span><\/span><\/p>\n

a) Fases 0 e 2.\u00a0 \u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0<\/b><\/span><\/span><\/span><\/p>\n

b) Fases 0 e 3.\u00a0 \u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0<\/b><\/span><\/span><\/span><\/p>\n

c) Fases 1 e 2.\u00a0 \u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0<\/b><\/span><\/span><\/span><\/p>\n

d) Fases 2 e 0.\u00a0 \u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0<\/b><\/span><\/span><\/span><\/p>\n

e) Fases 3 e 1.\u00a0<\/b><\/span><\/span><\/span><\/p>\n

\u00a0<\/span><\/p>\n

43-(CESGRANRIO-RJ)<\/b><\/span><\/span><\/span> <\/b>Um sistema tridimensional de coordenadas ortogonais, graduadas em metros, encontra-se em um meio cuja constante eletrost\u00e1tica \u00e9 1,3.10<\/b><\/span><\/span><\/span>9<\/b><\/span><\/span><\/sup><\/span>N.m<\/b><\/span><\/span><\/span>2<\/b><\/span><\/span><\/sup><\/span>\/C<\/b><\/span><\/span><\/span>2<\/b><\/span><\/span><\/sup><\/span>\u00a0 Nesse meio, h\u00e1 apenas tr\u00eas cargas positivas puntiformes Q<\/b><\/span><\/span><\/span>1<\/b><\/span><\/span><\/sub><\/span>, Q<\/b><\/span><\/span><\/span>2<\/b><\/span><\/span><\/sub><\/span>\u00a0<\/b><\/span><\/span><\/span>e Q<\/b><\/span><\/span><\/span>3<\/b><\/span><\/span><\/sub><\/span>, todas<\/b><\/span><\/span><\/span><\/p>\n

\"\"<\/p>\n

com carga igual a 1,44.10<\/b><\/span><\/span><\/span>-4<\/b><\/span><\/span><\/sup><\/span>\u00a0<\/b><\/span><\/span><\/span>C. Essas cargas est\u00e3o fixas, respectivamente, nos pontos (0,b,c), (a,0,c) e (a,b,0). Os n\u00fameros a, b e c (c < a < b) s\u00e3o as ra\u00edzes da equa\u00e7\u00e3o x<\/b><\/span><\/span><\/span>3<\/b><\/span><\/span><\/sup><\/span>\u00a0<\/b><\/span><\/span><\/span>\u2013 19x<\/b><\/span><\/span><\/span>2<\/b><\/span><\/span><\/sup><\/span>\u00a0<\/b><\/span><\/span><\/span>+ 96x \u2013 144 = 0.<\/b><\/span><\/span><\/span><\/p>\n

Adotando-se o referencial no infinito, o potencial el\u00e9trico, em kV, gerado pela carga Q<\/b><\/span><\/span><\/span>3<\/b><\/span><\/span><\/sub><\/span>\u00a0<\/b><\/span><\/span><\/span>no ponto (0,0,c) \u00e9<\/b><\/span><\/span><\/span><\/p>\n

\"\"<\/p>\n

44- (ITA-SP)\u00a0<\/b><\/span><\/span><\/span><\/p>\n

\"\"<\/p>\n

Considere as cargas el\u00e9tricas q<\/b><\/span><\/span><\/span>1<\/b><\/span><\/span><\/sub><\/span>\u00a0<\/b><\/span><\/span><\/span>= 1 C, situada em x = \u2013 2 m, e q<\/b><\/span><\/span><\/span>2<\/b><\/span><\/span><\/sub><\/span>\u00a0<\/b><\/span><\/span><\/span>= \u2013 2 C, situada em x = \u2013 8 m. Ent\u00e3o, o lugar geom\u00e9trico dos pontos de potencial nulo \u00e9<\/b><\/span><\/span><\/span><\/p>\n

a) uma esfera que corta o eixo x nos pontos x = \u2013 4 m e x = 4m.\u00a0<\/b><\/span><\/span><\/span><\/p>\n

b) uma esfera que corta o eixo x nos pontos x = \u2013 16 m e x = 16 m.\u00a0<\/b><\/span><\/span><\/span><\/p>\n

c) um elipsoide que corta o eixo x nos pontos x = \u2013 4 m e x = 16 m.\u00a0<\/b><\/span><\/span><\/span><\/p>\n

d) um hiperboloide que corta o eixo x no ponto x = \u2013 4 m.\u00a0<\/b><\/span><\/span><\/span><\/p>\n

e) um plano perpendicular ao eixo x que o corta no ponto x = \u2013 4 m.\u00a0<\/b><\/span><\/span><\/span><\/p>\n

\u00a0<\/span><\/p>\n

45-(UFG-G0)<\/b><\/span><\/span><\/span><\/p>\n

\"\"\u00a0 Uma carga puntiforme Q gera uma superf\u00edcie equipotencial de 2,0V a uma dist\u00e2ncia de 1,0m de sua posi\u00e7\u00e3o. Tendo<\/b><\/span><\/span><\/span><\/p>\n

\"\"<\/p>\n

\u00a0em vista o exposto, calcule a dist\u00e2ncia entre as superf\u00edcies equipotenciais que diferem dessa por 1,0V<\/b><\/span><\/span><\/span><\/p>\n

\u00a0<\/span><\/p>\n

46-(UERJ-RJ)\u00a0<\/b><\/span><\/span><\/span><\/p>\n

\"\"<\/p>\n

Em um laborat\u00f3rio, um pesquisador colocou uma esfera eletricamente carregada em uma c\u00e2mara na qual foi feito v\u00e1cuo.<\/b><\/span><\/span><\/span><\/p>\n

\"\"<\/p>\n

O potencial e o m\u00f3dulo do campo el\u00e9trico medidos a certa dist\u00e2ncia dessa esfera valem, respectivamente, 600 V e 200 V\/m.<\/b><\/span><\/span><\/span><\/p>\n

Determine o valor da carga el\u00e9trica da esfera.<\/b><\/span><\/span><\/span><\/p>\n

\u00a0<\/span><\/p>\n

47-(IFSP-SP)\u00a0<\/b><\/span><\/span><\/span><\/p>\n

\"\"<\/p>\n

Na figura a seguir, s\u00e3o representadas as linhas de for\u00e7a em uma regi\u00e3o de um campo el\u00e9trico. A partir dos pontos A, B, C, e D situados nesse campo, s\u00e3o feitas as seguintes afirma\u00e7\u00f5es:<\/b><\/span><\/span><\/span><\/p>\n

\"\"<\/p>\n

I. A intensidade do vetor campo el\u00e9trico no ponto B \u00e9 maior que no ponto C.<\/b><\/span><\/span><\/span><\/p>\n

II. O potencial el\u00e9trico no ponto D \u00e9 menor que no ponto C.<\/b><\/span><\/span><\/span><\/p>\n

III. Uma part\u00edcula carregada negativamente, abandonada no ponto B, se movimenta espontaneamente para regi\u00f5es de menor potencial el\u00e9trico.<\/b><\/span><\/span><\/span><\/p>\n

IV. A energia potencial el\u00e9trica de uma part\u00edcula positiva diminui quando se movimenta de B para A.<\/b><\/span><\/span><\/span><\/p>\n

\u00c9 correto o que se afirma apenas em<\/b><\/span><\/span><\/span><\/p>\n

a) I. \u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0<\/b><\/span><\/span><\/span><\/p>\n

b) I e IV.\u00a0 \u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0<\/b><\/span><\/span><\/span><\/p>\n

c) II e III.\u00a0 \u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0<\/b><\/span><\/span><\/span><\/p>\n

d) II e IV.\u00a0 \u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0<\/b><\/span><\/span><\/span><\/p>\n

e) I, II e III.\u00a0<\/b><\/span><\/span><\/span><\/p>\n

\u00a0<\/span><\/p>\n

48-(UFPE-PE)<\/b><\/span><\/span><\/span><\/p>\n

\"\"<\/p>\n

O gr\u00e1fico mostra a depend\u00eancia do potencial el\u00e9trico criado por uma carga pontual, no v\u00e1cuo, em fun\u00e7\u00e3o da dist\u00e2ncia \u00e0<\/b><\/span><\/span><\/span><\/p>\n

\"\"<\/p>\n

carga. Determine o valor da carga el\u00e9trica. D\u00ea a sua resposta em unidades de 10<\/b><\/span><\/span><\/span>-9<\/b><\/span><\/span><\/sup><\/span>\u00a0<\/b><\/span><\/span><\/span>C.<\/b><\/span><\/span><\/span><\/p>\n

\u00a0<\/span><\/p>\n

49-(FGV-SP)<\/b><\/span><\/span><\/span><\/p>\n

\"\"<\/p>\n

A figura seguinte representa algumas linhas de for\u00e7a de um campo el\u00e9trico uniforme e tr\u00eas pontos internos A, B e C desse campo. A reta que passa pelos pontos A e C \u00e9 perpendicular \u00e0s linhas de for\u00e7a.<\/b><\/span><\/span><\/span><\/p>\n

\"\"<\/p>\n

\u00c9 correto afirmar que<\/b><\/span><\/span><\/span><\/p>\n

(A) A e B t\u00eam o mesmo potencial el\u00e9trico, sendo este maior que o de C.<\/b><\/span><\/span><\/span><\/p>\n

(B) A e B t\u00eam o mesmo potencial el\u00e9trico, sendo este menor que o de C.<\/b><\/span><\/span><\/span><\/p>\n

(C) A e C t\u00eam o mesmo potencial el\u00e9trico, sendo este maior que o de B.<\/b><\/span><\/span><\/span><\/p>\n

(D) os potenciais el\u00e9tricos dos pontos A, B e C guardam a rela\u00e7\u00e3o V<\/b><\/span><\/span><\/span>A<\/b><\/span><\/span><\/sub><\/span><V<\/b><\/span><\/span><\/span>B<\/b><\/span><\/span><\/sub><\/span><V<\/b><\/span><\/span><\/span>C<\/b><\/span><\/span><\/sub><\/span>.<\/b><\/span><\/span><\/span><\/p>\n

(E) os potenciais el\u00e9tricos dos pontos A, B e C guardam a rela\u00e7\u00e3o V<\/b><\/span><\/span><\/span>A<\/b><\/span><\/span><\/sub><\/span>>V<\/b><\/span><\/span><\/span>B<\/b><\/span><\/span><\/sub><\/span>>V<\/b><\/span><\/span><\/span>C<\/b><\/span><\/span><\/sub><\/span>.<\/b><\/span><\/span><\/span><\/p>\n

\u00a0<\/span><\/p>\n

50-(AFA)<\/b><\/span><\/span><\/span><\/p>\n

\"\"<\/p>\n

A figura abaixo representa as linhas de for\u00e7a de um determinado campo el\u00e9trico.<\/b><\/span><\/span><\/span><\/p>\n

\"\"<\/p>\n

Sendo V<\/b><\/span><\/span><\/span>A<\/b><\/span><\/span><\/sub><\/span>, V<\/b><\/span><\/span><\/span>B<\/b><\/span><\/span><\/sub><\/span>, e V<\/b><\/span><\/span><\/span>C<\/b><\/span><\/span><\/sub><\/span>\u00a0<\/b><\/span><\/span><\/span>os potenciais eletrost\u00e1ticos em tr\u00eas pontos A, B e C, respectivamente, com\u00a0 0 < V<\/b><\/span><\/span><\/span>A<\/b><\/span><\/span><\/sub><\/span>\u00a0<\/b><\/span><\/span><\/sub><\/span>– V<\/b><\/span><\/span><\/span>C<\/b><\/span><\/span><\/sub><\/span>\u00a0<\/b><\/span><\/span><\/sub><\/span>< V<\/b><\/span><\/span><\/span>\u00a0<\/b><\/span><\/span><\/span>B<\/b><\/span><\/span><\/sub><\/span>\u00a0<\/b><\/span><\/span><\/sub><\/span>– V<\/b><\/span><\/span><\/span>C<\/b><\/span><\/span><\/sub><\/span>, pode-se afirmar que a<\/b><\/span><\/span><\/span><\/p>\n

posi\u00e7\u00e3o desses pontos \u00e9 melhor representada na alternativa<\/b><\/span><\/span><\/span><\/p>\n

\"\"<\/p>\n

\u00a0<\/span><\/p>\n

51-(MACKENZIE-SP)<\/b><\/span><\/span><\/span><\/p>\n

\"\"<\/p>\n

Um aluno, ao estudar F\u00edsica, encontra no seu livro a seguinte quest\u00e3o: \u201cNo v\u00e1cuo ( k = 9.10<\/b><\/span><\/span><\/span>9<\/b><\/span><\/span><\/sup><\/span>\u00a0<\/b><\/span><\/span><\/sub><\/span>N.m<\/b><\/span><\/span><\/span>2<\/b><\/span><\/span><\/sup><\/span>\/C<\/b><\/span><\/span><\/span>2<\/b><\/span><\/span><\/sup><\/span>),<\/b><\/span><\/span><\/span><\/p>\n

\"\"<\/p>\n

uma carga puntiforme Q gera, \u00e0 dist\u00e2ncia D, um campo el\u00e9trico de intensidade 360 N\/C e um potencial el\u00e9trico de 180 V, em rela\u00e7\u00e3o ao \u00a0infinito\u201d. A partir dessa afirma\u00e7\u00e3o, o aluno determinou o valor correto dessa carga como sendo<\/b><\/span><\/span><\/span><\/p>\n

\"\"<\/p>\n

\u00a0<\/span><\/p>\n

52-(FUVEST-SP)<\/b><\/span><\/span><\/span><\/p>\n

\"\"<\/p>\n

Em uma aula de laborat\u00f3rio, os estudantes foram divididos em dois grupos. O\u00a0 grupo A fez<\/b><\/span><\/span><\/span><\/p>\n

\"\"<\/p>\n

experimentos com o objetivo de desenhar linhas de campo el\u00e9trico e magn\u00e9tico. Os desenhos feitos est\u00e3o apresentados nas figuras I, II, III e IV abaixo.<\/b><\/span><\/span><\/span><\/p>\n

\"\"<\/p>\n

Aos alunos do grupo B, coube analisar os desenhos produzidos pelo grupo A e formular hip\u00f3teses. Dentre elas, a \u00fanica correta \u00e9 que as figuras I, II, III e IV podem representar, respectivamente, linhas de campo<\/b><\/span><\/span><\/span><\/p>\n

a) eletrost\u00e1tico, eletrost\u00e1tico, magn\u00e9tico e magn\u00e9tico. \u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0<\/b><\/span><\/span><\/span><\/p>\n

b) magn\u00e9tico, magn\u00e9tico, eletrost\u00e1tico e eletrost\u00e1tico.<\/b><\/span><\/span><\/span><\/p>\n

c) eletrost\u00e1tico, magn\u00e9tico, eletrost\u00e1tico e magn\u00e9tico. \u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0<\/b><\/span><\/span><\/span><\/p>\n

d) magn\u00e9tico, eletrost\u00e1tico, eletrost\u00e1tico e magn\u00e9tico.<\/b><\/span><\/span><\/span><\/p>\n

e) eletrost\u00e1tico, magn\u00e9tico, magn\u00e9tico e magn\u00e9tico.<\/b><\/span><\/span><\/span><\/p>\n

 <\/p>\n

Confira a resolu\u00e7\u00e3o comentada dos exerc\u00edcios<\/span><\/a><\/h3>\n","protected":false},"excerpt":{"rendered":"

Exerc\u00edcios de vestibulares com resolu\u00e7\u00f5es comentadas sobre Linhas de For\u00e7a (de campo) e Potencial Eletrost\u00e1tico 01-(UFPA) Com rela\u00e7\u00e3o \u00e0s linhas de for\u00e7a de um campo el\u00e9trico, pode-se afirmar que s\u00e3o linhas imagin\u00e1rias:\u00a0 \u00a0a) tais que a tangente a elas em qualquer ponto tem a mesma dire\u00e7\u00e3o do campo el\u00e9trico; \u00a0b) tais que a perpendicular a elas em qualquer ponto tem<\/p>\n","protected":false},"author":1,"featured_media":0,"parent":1638,"menu_order":0,"comment_status":"closed","ping_status":"closed","template":"","meta":{"om_disable_all_campaigns":false,"_monsterinsights_skip_tracking":false,"_monsterinsights_sitenote_active":false,"_monsterinsights_sitenote_note":"","_monsterinsights_sitenote_category":0,"footnotes":""},"class_list":["post-1640","page","type-page","status-publish","hentry"],"aioseo_notices":[],"_links":{"self":[{"href":"https:\/\/fisicaevestibular.com.br\/novo\/wp-json\/wp\/v2\/pages\/1640","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/fisicaevestibular.com.br\/novo\/wp-json\/wp\/v2\/pages"}],"about":[{"href":"https:\/\/fisicaevestibular.com.br\/novo\/wp-json\/wp\/v2\/types\/page"}],"author":[{"embeddable":true,"href":"https:\/\/fisicaevestibular.com.br\/novo\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/fisicaevestibular.com.br\/novo\/wp-json\/wp\/v2\/comments?post=1640"}],"version-history":[{"count":4,"href":"https:\/\/fisicaevestibular.com.br\/novo\/wp-json\/wp\/v2\/pages\/1640\/revisions"}],"predecessor-version":[{"id":10620,"href":"https:\/\/fisicaevestibular.com.br\/novo\/wp-json\/wp\/v2\/pages\/1640\/revisions\/10620"}],"up":[{"embeddable":true,"href":"https:\/\/fisicaevestibular.com.br\/novo\/wp-json\/wp\/v2\/pages\/1638"}],"wp:attachment":[{"href":"https:\/\/fisicaevestibular.com.br\/novo\/wp-json\/wp\/v2\/media?parent=1640"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}