{"id":1855,"date":"2016-01-25T01:03:56","date_gmt":"2016-01-25T01:03:56","guid":{"rendered":"http:\/\/fisicaevestibular.com.br\/novo\/?page_id=1855"},"modified":"2024-08-19T15:29:13","modified_gmt":"2024-08-19T15:29:13","slug":"exercicios-de-vestibulares-com-resolucao-comentada-sobre-galvanometro-como-amperimetro-e-como-voltimetro-ponte-de-wheatstone","status":"publish","type":"page","link":"https:\/\/fisicaevestibular.com.br\/novo\/eletricidade\/eletrodinamica\/galvanometro-como-amperimetro-e-como-voltimetro-ponte-de-wheatstone\/exercicios-de-vestibulares-com-resolucao-comentada-sobre-galvanometro-como-amperimetro-e-como-voltimetro-ponte-de-wheatstone\/","title":{"rendered":"Ponte de Wheatstone – Resolu\u00e7\u00e3o"},"content":{"rendered":"

Exerc\u00edcios de vestibulares com resolu\u00e7\u00e3o comentada sobre<\/b><\/span><\/span><\/span><\/p>\n

Galvan\u00f4metro como Amper\u00edmetro e como Volt\u00edmetro \u2013 Ponte de Wheatstone<\/b><\/span><\/span><\/span><\/p>\n

 <\/p>\n

 <\/p>\n

\u00a0<\/span>01-(FUVEST-SP)<\/b><\/span><\/span><\/span> Um galvan\u00f4metro permite a passagem de corrente m\u00e1xima i<\/b><\/span><\/span><\/span>G<\/b><\/span><\/span><\/sub><\/span>.<\/b><\/span><\/span><\/span><\/p>\n

\"\"<\/p>\n

A finalidade de se colocar uma resist\u00eancia em paralelo com ele \u00e9:<\/b><\/span><\/span><\/span><\/p>\n

\u00a0a) fazer passar uma corrente mais intensa que i<\/b><\/span><\/span><\/span>G<\/b><\/span><\/span><\/sub><\/span>\u00a0<\/b><\/span><\/span><\/span>pelo galvan\u00f4metro sem danific\u00e1-lo;<\/b><\/span><\/span><\/span><\/p>\n

b) permitir a medida de corrente (I) mais intensa que i<\/b><\/span><\/span><\/span>G<\/b><\/span><\/span><\/sub><\/span>;<\/b><\/span><\/span><\/span><\/p>\n

c) permitir a medida de tens\u00f5es elevadas;<\/b><\/span><\/span><\/span><\/p>\n

d) as tr\u00eas resolu\u00e7\u00f5es anteriores;<\/b><\/span><\/span><\/span><\/p>\n

e) fazer passar uma corrente menos intensa que i<\/b><\/span><\/span><\/span>G<\/b><\/span><\/span><\/sub><\/span><\/p>\n


\n<\/b><\/span><\/span><\/span>02-(MACKENZIE-SP)<\/b><\/span><\/span><\/span> \u00c9 dado um galvan\u00f4metro de resist\u00eancia 10W<\/b><\/span><\/span><\/span>\u00a0<\/b><\/span><\/span><\/span>e fundo de escala 1,0V. Qual deve ser o valor da resist\u00eancia s\u00e9rie para medir 10V? Qual deve ser o fator de multiplica\u00e7\u00e3o?<\/b><\/span><\/span><\/span><\/p>\n

\u00a0a) 90<\/b><\/span><\/span><\/span>\u00a0<\/b><\/span><\/span><\/span>W<\/b><\/span><\/span><\/span>\u00a0<\/b><\/span><\/span><\/span>e 10\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) 9<\/b><\/span><\/span><\/span>\u00a0<\/b><\/span><\/span><\/span>W<\/b><\/span><\/span><\/span>\u00a0<\/b><\/span><\/span><\/span>e 10\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) 100<\/b><\/span><\/span><\/span>\u00a0<\/b><\/span><\/span><\/span>W<\/b><\/span><\/span><\/span>\u00a0<\/b><\/span><\/span><\/span>e 10\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) 10<\/b><\/span><\/span><\/span>\u00a0<\/b><\/span><\/span><\/span>W<\/b><\/span><\/span><\/span>\u00a0<\/b><\/span><\/span><\/span>e 100\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) 1000<\/b><\/span><\/span><\/span>\u00a0<\/b><\/span><\/span><\/span>W<\/b><\/span><\/span><\/span>\u00a0<\/b><\/span><\/span><\/span>e 10<\/b><\/span><\/span><\/span><\/p>\n

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

03. (MACKENZIE)<\/b><\/span><\/span><\/span> Usando um volt\u00edmetro de fundo de escala 20V e resist\u00eancia interna de 2000W, desejamos medir uma ddp de 100V. A resist\u00eancia do resistor adicional que devemos associar a esse volt\u00edmetro \u00e9:<\/b><\/span><\/span><\/span><\/p>\n

\"\"<\/p>\n

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

04-(UFG-GO)<\/b><\/span><\/span><\/span> Um laborat\u00f3rio possui um galvan\u00f4metro de resist\u00eancia interna 100 \u03a9 e corrente de fundo de escala 2,0 mA. Calcule a resist\u00eancia necess\u00e1ria para utiliz\u00e1-lo como:<\/b><\/span><\/span><\/span><\/p>\n

A) um amper\u00edmetro para medir uma corrente m\u00e1xima de 50 mA;<\/b><\/span><\/span><\/span><\/p>\n

B) um volt\u00edmetro para medir uma tens\u00e3o m\u00e1xima de 20 V.<\/b><\/span><\/span><\/span><\/p>\n

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

05-(UFRS-RS)<\/b><\/span><\/span><\/span> Selecione a alternativa que preenche corretamente as lacunas do texto abaixo, na ordem em que elas aparecem.<\/b><\/span><\/span><\/span><\/p>\n

Um “galvan\u00f4metro” \u00e9 um aparelho delicado e sens\u00edvel capaz de medir uma corrente el\u00e9trica cont\u00ednua, I, muito pequena, da ordem de alguns microamp\u00e8res ou, quando muito, miliamp\u00e8res. Para medir correntes el\u00e9tricas maiores do que essas, usa-se um “amper\u00edmetro”, que \u00e9 um galvan\u00f4metro modificado da maneira representada na figura adiante.<\/b><\/span><\/span><\/span><\/p>\n

\"\"<\/p>\n

Constr\u00f3i-se um amper\u00edmetro a partir de um galvan\u00f4metro, ligando-se a resist\u00eancia interna R<\/b><\/span><\/span><\/span>G<\/b><\/span><\/span><\/sub><\/span>\u00a0<\/b><\/span><\/span><\/span>do galvan\u00f4metro em paralelo com uma resist\u00eancia R<\/b><\/span><\/span><\/span>S<\/b><\/span><\/span><\/sub><\/span>, chamada de ‘shunt’ (palavra inglesa que significa desvio). Assim, para se obter um amper\u00edmetro cuja “corrente de fundo de escala” seja 10 vezes maior do que a do galvan\u00f4metro usado, …….. da corrente el\u00e9trica I dever\u00e1 passar pelo galvan\u00f4metro, e o valor de R<\/b><\/span><\/span><\/span>S<\/b><\/span><\/span><\/sub><\/span>\u00a0<\/b><\/span><\/span><\/span>dever\u00e1 ser …….. do que o valor de R<\/b><\/span><\/span><\/span>G<\/b><\/span><\/span><\/sub><\/span>.<\/b><\/span><\/span><\/span><\/p>\n

(Dado: A “corrente de fundo de escala” \u00e9 o valor m\u00e1ximo de corrente el\u00e9trica que o amper\u00edmetro ou o galvan\u00f4metro podem medir.)<\/b><\/span><\/span><\/span><\/p>\n

a) 1\/9 – 9 vezes menor\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0<\/b><\/span><\/span><\/span><\/p>\n

b) 1\/10 – 9 vezes menor\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0<\/b><\/span><\/span><\/span><\/p>\n

c) 1\/10 – 10 vezes maior\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0<\/b><\/span><\/span><\/span><\/p>\n

d) 9\/10 \u2013 9 vezes maior<\/b><\/span><\/span><\/span><\/p>\n

e) 9\/10 \u2013 10 vezes maior<\/b><\/span><\/span><\/span><\/p>\n

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

06- (UNESP-SP)<\/b><\/span><\/span><\/span> A corrente que corresponde \u00e0 deflex\u00e3o m\u00e1xima do ponteiro de um galvan\u00f4metro \u00e9 de 1,0mA e sua resist\u00eancia \u00e9 de 0,5\u2126. Qual deve ser o valor da resist\u00eancia de um resistor que precisa ser colocado nesse aparelho para que ele se transforme num volt\u00edmetro apto a medir at\u00e9 10V? Como deve ser colocado esse resistor, em s\u00e9rie ou em paralelo com o galvan\u00f4metro?<\/b><\/span><\/span><\/span><\/p>\n

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

07-(UERJ-RJ)<\/b><\/span><\/span><\/span> O galvan\u00f4metro abaixo tem resist\u00eancia interna de 100\u2126 e sofre a m\u00e1xima deflex\u00e3o com a passagem de uma corrente de 1,0.10<\/b><\/span><\/span><\/span>-4<\/b><\/span><\/span><\/sup><\/span>\u00a0<\/b><\/span><\/span><\/span>A. O instrumento \u00e9 acoplado a um volt\u00edmetro de escala m\u00faltipla, como indicam os valores que representam as leituras m\u00e1ximas de cada escala no esquema que se segue.<\/b><\/span><\/span><\/span><\/p>\n

\"\"<\/p>\n

Os valores das resist\u00eancias R<\/b><\/span><\/span><\/span>1<\/b><\/span><\/span><\/sub><\/span>, R<\/b><\/span><\/span><\/span>2<\/b><\/span><\/span><\/sub><\/span>\u00a0<\/b><\/span><\/span><\/span>e R<\/b><\/span><\/span><\/span>3<\/b><\/span><\/span><\/sub><\/span>, em ohms, devem ser de, respectivamente:<\/b><\/span><\/span><\/span><\/p>\n

a) 9,9.10<\/b><\/span><\/span><\/span>2<\/b><\/span><\/span><\/sup><\/span>; 9,9.10<\/b><\/span><\/span><\/span>3<\/b><\/span><\/span><\/sup><\/span>\u00a0<\/b><\/span><\/span><\/span>e 9,9.10<\/b><\/span><\/span><\/span>4<\/b><\/span><\/span><\/sup><\/span>\u00a0\u00a0\u00a0\u00a0<\/b><\/span><\/span><\/span><\/p>\n

b) 9,0.10<\/b><\/span><\/span><\/span>3<\/b><\/span><\/span><\/sup><\/span>; 9,0.10<\/b><\/span><\/span><\/span>4<\/b><\/span><\/span><\/sup><\/span>\u00a0<\/b><\/span><\/span><\/span>e 9,0.10<\/b><\/span><\/span><\/span>5<\/b><\/span><\/span><\/sup><\/span>\u00a0\u00a0\u00a0\u00a0\u00a0<\/b><\/span><\/span><\/span><\/p>\n

c) 9,9.10<\/b><\/span><\/span><\/span>3<\/b><\/span><\/span><\/sup><\/span>; 9,0.10<\/b><\/span><\/span><\/span>4<\/b><\/span><\/span><\/sup><\/span>\u00a0<\/b><\/span><\/span><\/span>e 9,0.10<\/b><\/span><\/span><\/span>5<\/b><\/span><\/span><\/sup><\/span>\u00a0\u00a0\u00a0\u00a0\u00a0<\/b><\/span><\/span><\/span><\/p>\n

d) 9,9.10<\/b><\/span><\/span><\/span>3<\/b><\/span><\/span><\/sup><\/span>; 9,9.10<\/b><\/span><\/span><\/span>4<\/b><\/span><\/span><\/sup><\/span>\u00a0<\/b><\/span><\/span><\/span>e 9,9.10<\/b><\/span><\/span><\/span>5<\/b><\/span><\/span><\/sup><\/span><\/p>\n

e) 9,0.10<\/b><\/span><\/span><\/span>4<\/b><\/span><\/span><\/sup><\/span>; 9,0.10<\/b><\/span><\/span><\/span>5<\/b><\/span><\/span><\/sup><\/span>\u00a0<\/b><\/span><\/span><\/span>e 9,0.10<\/b><\/span><\/span><\/span>6<\/b><\/span><\/span><\/sup><\/span><\/p>\n

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

08-(UNESP-SP)<\/b><\/span><\/span><\/span> Pretende-se medir a corrente no circuito abaixo intercalando-se entre os pontos A e B um amper\u00edmetro que tem resist\u00eancia interna de 1,5\u2126.<\/b><\/span><\/span><\/span><\/p>\n

\"\"<\/p>\n

Acontece que o m\u00e1ximo valor que o instrumento mede (fundo de escala) \u00e9 3,0A, e a corrente no circuito \u00e9 maior que isso. Aumentando-se o fundo de escala para 4,5 A, o instrumento pode ser utilizado. S\u00e3o fornecidos resistores ( r )\u00a0 que devem ser ligados ao amper\u00edmetro , na forma indicada, de modo que sua escala seja ampliada para 4,5 A. Que valor de resist\u00eancia ( r )\u00a0 satisfaz o requisito?<\/b><\/span><\/span><\/span><\/p>\n

a) 4,0 \u2126\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

b) 3,0 \u2126\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) 2,0 \u2126\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) 1,0 \u2126\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) 0,5 \u2126<\/b><\/span><\/span><\/span><\/p>\n

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

09-(UFB)<\/b><\/span><\/span><\/span> Na parede de uma loja de produtos el\u00e9tricos est\u00e3o expostos cinco ventiladores id\u00eanticos (A,B,C,D e E) e desligados, Os pontos M e N est\u00e3o ligados \u00e0 uma rede de tens\u00e3o el\u00e9trica constante de 117V, conforme o esquema da figura.<\/b><\/span><\/span><\/span><\/p>\n

\"\"<\/p>\n

Ligando-se o interruptor I, qual dos ventiladores n\u00e3o funcionar\u00e1? Justifique.<\/b><\/span><\/span><\/span><\/p>\n

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

10-(UEL-PR)<\/b><\/span><\/span><\/span> Abaixo est\u00e1 esquematizado um trecho de circuito em que todos os resistores s\u00e3o iguais.
\nEntre os pontos A e F existe uma diferen\u00e7a de potencial de 500V.<\/b><\/span><\/span><\/span><\/p>\n

\"\"<\/p>\n

Entretanto, pode-se tocar simultaneamente em dois pontos desse circuito sem tomar um “choque”. Esses pontos s\u00e3o:<\/b><\/span><\/span><\/span><\/p>\n

\"\"<\/p>\n

11-(UFLA-MG)<\/b><\/span><\/span><\/span> A ponte de Wheatstone mostrada abaixo estar\u00e1 em equil\u00edbrio quando o galvan\u00f4metro G indicar zero volt. Para que isso ocorra, R<\/b><\/span><\/span><\/span>1<\/b><\/span><\/span><\/sub><\/span>\u00a0<\/b><\/span><\/span><\/span>deve ter valor igual a:<\/b><\/span><\/span><\/span><\/p>\n

\"\"<\/p>\n

a) R\/3\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) R\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) 2R\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) R<\/b><\/span><\/span><\/span>2<\/b><\/span><\/span><\/sup><\/span>\/2\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)R<\/b><\/span><\/span><\/span>2<\/b><\/span><\/span><\/sup><\/span>\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

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

12-(UEL-PR)<\/b><\/span><\/span><\/span> No circuito esquematizado, R<\/b><\/span><\/span><\/span>1<\/b><\/span><\/span><\/sub><\/span>=210\u2126, R<\/b><\/span><\/span><\/span>2<\/b><\/span><\/span><\/sub><\/span>=30\u2126, AB \u00e9 um fio homog\u00eaneo de se\u00e7\u00e3o reta transversal constante e resist\u00eancia 50\u2126 e comprimento 500mm. Obteve-se o equil\u00edbrio do galvan\u00f4metro para L=150mm. O valor de X \u00e9, em ohms:<\/b><\/span><\/span><\/span><\/p>\n

\"\"<\/p>\n

\"\"<\/p>\n

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

13-(UNICAMP-SP)<\/b><\/span><\/span><\/span> A varia\u00e7\u00e3o de uma resist\u00eancia el\u00e9trica com a temperatura pode ser utilizada para medir a temperatura de um corpo. Considere uma resist\u00eancia R que varia com a temperatura \u03b8 de acordo com a express\u00e3o<\/b><\/span><\/span><\/span>\u00a0<\/b><\/span><\/span><\/span>R=R<\/b><\/span><\/span><\/span>o<\/b><\/span><\/span><\/sub><\/span>(1 + \u03b1\u03b8)<\/b><\/span><\/span><\/span>\u00a0<\/b><\/span><\/span><\/span>onde R<\/b><\/span><\/span><\/span>o<\/b><\/span><\/span><\/sub><\/span>=100\u2126, \u03b1=4.10<\/b><\/span><\/span><\/span>-3o<\/b><\/span><\/span><\/sup><\/span>C<\/b><\/span><\/span><\/span>-1<\/b><\/span><\/span><\/sup><\/span>\u00a0<\/b><\/span><\/span><\/sub><\/span>e \u03b8 \u00e9 dada em graus celsius. Esta resist\u00eancia est\u00e1 em equil\u00edbrio t\u00e9rmico com o corpo, cuja temperatura \u03b8 se deseja conhecer. Para medir o valor de R, ajusta-se a resist\u00eancia R<\/b><\/span><\/span><\/span>2<\/b><\/span><\/span><\/sub><\/span>, indicada no circuito abaixo, at\u00e9 que a corrente medida pelo amper\u00edmetro no trecho AB seja nula.<\/b><\/span><\/span><\/span><\/p>\n

\"\"<\/p>\n

a) Qual a temperatura \u03b8 do corpo quando a resist\u00eancia R<\/b><\/span><\/span><\/span>2<\/b><\/span><\/span><\/sub><\/span>\u00a0<\/b><\/span><\/span><\/span>for igual a 108\u2126?<\/b><\/span><\/span><\/span><\/p>\n

b) A corrente atrav\u00e9s da resist\u00eancia R \u00e9 igual a 5,0.10<\/b><\/span><\/span><\/span>-3<\/b><\/span><\/span><\/sup><\/span>A. Qual a diferen\u00e7a de potencial entre os pontos C e D indicados na figura?<\/b><\/span><\/span><\/span><\/p>\n

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

14-(UFRN-RN)<\/b><\/span><\/span><\/span> No circuito da figura abaixo, o galvan\u00f4metro indica uma corrente nula.<\/b><\/span><\/span><\/span><\/p>\n

\"\"<\/p>\n

Neste caso, pode-se afirmar que:<\/b><\/span><\/span><\/span><\/p>\n

a) i<\/b><\/span><\/span><\/span>1<\/b><\/span><\/span><\/sub><\/span>R<\/b><\/span><\/span><\/span>4<\/b><\/span><\/span><\/sub><\/span>\u00a0<\/b><\/span><\/span><\/span>+ i<\/b><\/span><\/span><\/span>2<\/b><\/span><\/span><\/sub><\/span>R<\/b><\/span><\/span><\/span>3<\/b><\/span><\/span><\/sub><\/span>=0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0<\/b><\/span><\/span><\/span><\/p>\n

b) i<\/b><\/span><\/span><\/span>1<\/b><\/span><\/span><\/sub><\/span>R<\/b><\/span><\/span><\/span>1<\/b><\/span><\/span><\/sub><\/span>\u00a0<\/b><\/span><\/span><\/span>\u2013 i<\/b><\/span><\/span><\/span>2<\/b><\/span><\/span><\/sub><\/span>R<\/b><\/span><\/span><\/span>3<\/b><\/span><\/span><\/sub><\/span>=0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0<\/b><\/span><\/span><\/span><\/p>\n

c) i<\/b><\/span><\/span><\/span>1<\/b><\/span><\/span><\/sub><\/span>R<\/b><\/span><\/span><\/span>4<\/b><\/span><\/span><\/sub><\/span>\u00a0<\/b><\/span><\/span><\/span>\u2013 i<\/b><\/span><\/span><\/span>2<\/b><\/span><\/span><\/sub><\/span>R<\/b><\/span><\/span><\/span>3<\/b><\/span><\/span><\/sub><\/span>=0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0<\/b><\/span><\/span><\/span><\/p>\n

d) i<\/b><\/span><\/span><\/span>1<\/b><\/span><\/span><\/sub><\/span>R<\/b><\/span><\/span><\/span>4<\/b><\/span><\/span><\/sub><\/span>\u00a0<\/b><\/span><\/span><\/span>+ i<\/b><\/span><\/span><\/span>2<\/b><\/span><\/span><\/sub><\/span>R<\/b><\/span><\/span><\/span>2<\/b><\/span><\/span><\/sub><\/span>=0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0<\/b><\/span><\/span><\/span><\/p>\n

e) i<\/b><\/span><\/span><\/span>1<\/b><\/span><\/span><\/sub><\/span>R<\/b><\/span><\/span><\/span>1<\/b><\/span><\/span><\/sub><\/span>\u00a0<\/b><\/span><\/span><\/span>+ i<\/b><\/span><\/span><\/span>2<\/b><\/span><\/span><\/sub><\/span>R<\/b><\/span><\/span><\/span>2<\/b><\/span><\/span><\/sub><\/span>=0<\/b><\/span><\/span><\/span><\/p>\n

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

15-(UNICAMP-SP)<\/b><\/span><\/span><\/span> No circuito abaixo a corrente na resist\u00eancia de 5\u2126 \u00e9 nula.<\/b><\/span><\/span><\/span><\/p>\n

\"\"<\/p>\n

a) Determine o valor da resist\u00eancia X<\/b><\/span><\/span><\/span><\/p>\n

b) Qual a corrente fornecida pela bateria?<\/b><\/span><\/span><\/span><\/p>\n

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

16-(UFSC)<\/b><\/span><\/span><\/span> O circuito fechado \u00e9 o de uma \u201cponte de fio\u201d e serve para determina\u00e7\u00e3o de uma resist\u00eancia desconhecida R<\/b><\/span><\/span><\/span>X<\/b><\/span><\/span><\/sub><\/span>.<\/b><\/span><\/span><\/span><\/p>\n

\"\"<\/p>\n

Sabendo que a ponte da figura est\u00e1 equilibrada , isto \u00e9, o galvan\u00f4metro G n\u00e3o acusa nenhuma passagem de corrente el\u00e9trica, determine o valor num\u00e9rico de R (em ohms), na situa\u00e7\u00e3o de equil\u00edbrio, considerando que L<\/b><\/span><\/span><\/span>1<\/b><\/span><\/span><\/sub><\/span>=20cm e L<\/b><\/span><\/span><\/span>2<\/b><\/span><\/span><\/sub><\/span>=50cm.<\/b><\/span><\/span><\/span><\/p>\n

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

17-(FUVEST)<\/b><\/span><\/span><\/span> Considere o circuito da figura, onde E=10V e R=1.000\u2126.<\/b><\/span><\/span><\/span><\/p>\n

\"\"<\/p>\n

a) Qual a leitura do amper\u00edmetro A?<\/b><\/span><\/span><\/span><\/p>\n

b) Qual a leitura do volt\u00edmetro V?<\/b><\/span><\/span><\/span><\/p>\n

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

18-(UNESP-SP)<\/b><\/span><\/span><\/span> Um circuito contendo quatro resistores \u00e9 alimentado por uma fonte de tens\u00e3o, conforme figura.<\/b><\/span><\/span><\/span><\/p>\n

\"\"<\/p>\n

Calcule o valor da resist\u00eancia R, sabendo-se que o potencial eletrost\u00e1tico em A \u00e9 igual ao potencial em B.<\/b><\/span><\/span><\/span><\/p>\n

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

19-(UFPE)<\/b><\/span><\/span><\/span> O circuito da figura \u00e9 formado por resistores id\u00eanticos, de resist\u00eancia igual a 42 ohms cada. Se, quando uma diferen\u00e7a de potencial de 100V \u00e9 aplicada entre os pontos A e B, a diferen\u00e7a de potencial entre A e C \u00e9 igual a 50V.<\/b><\/span><\/span><\/span><\/p>\n

\"\"<\/p>\n

Determine a diferen\u00e7a de potencial em volts entre os pontos D e B.<\/b><\/span><\/span><\/span><\/p>\n

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

20-(UnB-DF)<\/b><\/span><\/span><\/span> Quatro resistores iguais s\u00e3o ligados, formando um quadril\u00e1tero, cujos v\u00e9rtices s\u00e3o identificados pelas letras A, B, C e D. Entre os v\u00e9rtices A e C, diagonalmente opostos, \u00e9 ligada uma fonte de 6 volts. Se o potencial do v\u00e9rtice D vale 6 volts, calcule o potencial do v\u00e9rtice B, diametralmente oposto a D.<\/b><\/span><\/span><\/span><\/p>\n

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

21- (Mackenzie-SP)<\/b><\/span><\/span><\/span> No circuito a seguir, a ddp entre os terminais A e B \u00e9 de 60V e o galvan\u00f4metro G acusa uma intensidade de corrente el\u00e9trica zero. Se a ddp entre os terminais A e B for duplicada e o galvan\u00f4metro continuar acusando zero, poderemos afirmar que:<\/b><\/span><\/span><\/span><\/p>\n

\"\"<\/p>\n

a) a resist\u00eancia R permanecer\u00e1 constante e igual a 25 \u2126.\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0<\/b><\/span><\/span><\/span><\/p>\n

b) a resist\u00eancia R permanecer\u00e1 constante e igual a 15 \u2126.<\/b><\/span><\/span><\/span>\u00a0<\/b><\/span><\/span><\/span>
\nc) a resist\u00eancia R permanecer\u00e1 constante e igual a 10 \u2126.\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0<\/b><\/span><\/span><\/span><\/p>\n

d) a resist\u00eancia R, que era de 25 \u2126, ser\u00e1 alterada para 50 \u2126.<\/b><\/span><\/span><\/span>\u00a0<\/b><\/span><\/span><\/span>
\ne) a resist\u00eancia R, que era de 50 \u2126, ser\u00e1 alterada para 12,5 \u2126.<\/b><\/span><\/span><\/span><\/p>\n

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

22-<\/b><\/span><\/span><\/span>\u00a0<\/b><\/span><\/span><\/span>(Mackenzie-SP)<\/b><\/span><\/span><\/span> No circuito abaixo, para que ambos os amper\u00edmetros ideais, A<\/b><\/span><\/span><\/span>1<\/b><\/span><\/span><\/sub><\/span>\u00a0<\/b><\/span><\/span><\/span>e A<\/b><\/span><\/span><\/span>2<\/b><\/span><\/span><\/sub><\/span>, indiquem zero, \u00e9 necess\u00e1rio que as resist\u00eancias R<\/b><\/span><\/span><\/span>1<\/b><\/span><\/span><\/sub><\/span>\u00a0<\/b><\/span><\/span><\/span>e R<\/b><\/span><\/span><\/span>2<\/b><\/span><\/span><\/sub><\/span>\u00a0<\/b><\/span><\/span><\/span>valham, respectivamente, em ohms:<\/b><\/span><\/span><\/span><\/p>\n

\"\"<\/p>\n

a) 10 e 120\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) 40 e 90\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) 90 e 40\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) 40 e 10\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) 10 e 40<\/b><\/span><\/span><\/span><\/p>\n

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

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

\"\"<\/p>\n

A figura abaixo mostra quatro passarinhos pousados em um circuito el\u00e9trico ligado a uma fonte de tens\u00e3o, composto de fios ideais<\/b><\/span><\/span><\/span><\/p>\n

e cinco l\u00e2mpadas id\u00eanticas L.<\/b><\/span><\/span><\/span><\/p>\n

\"\"<\/p>\n

Ao ligar a chave Ch, o(s) passarinho(s) pelo(s) qual(ais) certamente n\u00e3o passar\u00e1(\u00e3o) corrente el\u00e9trica \u00e9(s\u00e3o) o(s) indicado(s)<\/b><\/span><\/span><\/span><\/p>\n

pelo(s) n\u00famero(s)<\/b><\/span><\/span><\/span><\/p>\n

\"\"<\/p>\n

 <\/p>\n

Confira o gabarito e resolu\u00e7\u00e3o comentada!<\/span><\/a><\/h3>\n","protected":false},"excerpt":{"rendered":"

Exerc\u00edcios de vestibulares com resolu\u00e7\u00e3o comentada sobre Galvan\u00f4metro como Amper\u00edmetro e como Volt\u00edmetro \u2013 Ponte de Wheatstone     \u00a001-(FUVEST-SP) Um galvan\u00f4metro permite a passagem de corrente m\u00e1xima iG. A finalidade de se colocar uma resist\u00eancia em paralelo com ele \u00e9: \u00a0a) fazer passar uma corrente mais intensa que iG\u00a0pelo galvan\u00f4metro sem danific\u00e1-lo; b) permitir a medida de corrente (I)<\/p>\n","protected":false},"author":1,"featured_media":0,"parent":1853,"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-1855","page","type-page","status-publish","hentry"],"aioseo_notices":[],"_links":{"self":[{"href":"https:\/\/fisicaevestibular.com.br\/novo\/wp-json\/wp\/v2\/pages\/1855","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=1855"}],"version-history":[{"count":3,"href":"https:\/\/fisicaevestibular.com.br\/novo\/wp-json\/wp\/v2\/pages\/1855\/revisions"}],"predecessor-version":[{"id":10535,"href":"https:\/\/fisicaevestibular.com.br\/novo\/wp-json\/wp\/v2\/pages\/1855\/revisions\/10535"}],"up":[{"embeddable":true,"href":"https:\/\/fisicaevestibular.com.br\/novo\/wp-json\/wp\/v2\/pages\/1853"}],"wp:attachment":[{"href":"https:\/\/fisicaevestibular.com.br\/novo\/wp-json\/wp\/v2\/media?parent=1855"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}