{"id":1687,"date":"2015-12-19T15:41:11","date_gmt":"2015-12-19T15:41:11","guid":{"rendered":"http:\/\/fisicaevestibular.com.br\/novo\/?page_id=1687"},"modified":"2025-01-08T18:55:27","modified_gmt":"2025-01-08T18:55:27","slug":"resolucao-comentada-dos-exercicios-de-vestibulares-sobre-corrente-eletrica","status":"publish","type":"page","link":"https:\/\/fisicaevestibular.com.br\/novo\/eletricidade\/eletrodinamica\/corrente-eletrica-eletrodinamica\/resolucao-comentada-dos-exercicios-de-vestibulares-sobre-corrente-eletrica\/","title":{"rendered":"Corrente El\u00e9trica – Resolu\u00e7\u00e3o"},"content":{"rendered":"

Resolu\u00e7\u00e3o comentada dos exerc\u00edcios de vestibulares sobre<\/b><\/span><\/span><\/span><\/p>\n

Corrente El\u00e9trica<\/b><\/span><\/span><\/span><\/p>\n

01<\/b><\/span><\/span><\/span>–<\/b><\/span><\/span><\/span> Q=\u00e1rea do ret\u00e2ngulo=b.h=2.4\u00a0 —\u00a0<\/b><\/span><\/span><\/span>\u00a0Q=8C<\/b><\/span><\/span><\/span><\/p>\n

02<\/b><\/span><\/span><\/span>–<\/b><\/span><\/span><\/span> entre zero e 0,6s\u00a0 —\u00a0 fio 1\u00a0 —\u00a0 Q<\/b><\/span><\/span><\/span>1<\/b><\/span><\/span><\/sub><\/span>=\u00e1rea do tri\u00e2ngulo e Q<\/b><\/span><\/span><\/span>2<\/b><\/span><\/span><\/sub><\/span>=\u00e1rea do trap\u00e9zio\u00a0 —\u00a0 observe na s figuras abaixo que a \u00e1rea<\/b><\/span><\/span><\/span><\/p>\n

\"\"<\/p>\n

do trap\u00e9zio \u00e9 maior que a \u00e1rea do tri\u00e2ngulo, ou seja, Q<\/b><\/span><\/span><\/span>2<\/b><\/span><\/span><\/sub><\/span>>Q<\/b><\/span><\/span><\/span>1<\/b><\/span><\/span><\/sub><\/span>.<\/b><\/span><\/span><\/span><\/p>\n

Entre 0,6s e 1,0s\u00a0 — Q<\/b><\/span><\/span><\/span>1<\/b><\/span><\/span><\/sub><\/span>\u2019=\u00e1rea do trap\u00e9zio da figura 1\u2019\u00a0 —\u00a0 Q<\/b><\/span><\/span><\/span>2<\/b><\/span><\/span><\/sub><\/span>\u2019=\u00e1rea do trap\u00e9zio da figura 2\u2019\u00a0 —\u00a0 observe nas figuras<\/b><\/span><\/span><\/span><\/p>\n

\"\"<\/p>\n

abaixo Q<\/b><\/span><\/span><\/span>1<\/b><\/span><\/span><\/sub><\/span>\u2019 > Q<\/b><\/span><\/span><\/span>2<\/b><\/span><\/span><\/sub><\/span>\u2019.<\/b><\/span><\/span><\/span><\/p>\n

Entre zero e 1,0s\u00a0 —\u00a0 observe que Q<\/b><\/span><\/span><\/span>2<\/b><\/span><\/span><\/sub><\/span>\u2019\u2019 > Q<\/b><\/span><\/span><\/span>1<\/b><\/span><\/span><\/sub><\/span>\u2019\u2019 pelas figuras abaixo<\/b><\/span><\/span><\/span><\/p>\n

\"\"<\/p>\n

R- D<\/b><\/span><\/span><\/span><\/p>\n

03<\/b><\/span><\/span><\/span>–<\/b><\/span><\/span><\/span> Q=\u00e1rea do tri\u00e2ngulo=b.h\/2=7,2.4.10<\/b><\/span><\/span><\/span>-3<\/b><\/span><\/span><\/sup><\/span>\/2=14,4.10<\/b><\/span><\/span><\/span>-3<\/b><\/span><\/span><\/sup><\/span>C\u00a0 —\u00a0 regra de tr\u00eas\u00a0 —\u00a0 1 e \u2013 1,6.10<\/b><\/span><\/span><\/span>-19<\/b><\/span><\/span><\/sup><\/span>C\u00a0 —\u00a0 n e \u2013 14,4.10<\/b><\/span><\/span><\/span>-3<\/b><\/span><\/span><\/sup><\/span>C\u00a0 —\u00a0<\/b><\/span><\/span><\/span><\/p>\n

1,6.10<\/b><\/span><\/span><\/span>-19<\/b><\/span><\/span><\/sup><\/span>.n=14,4.10<\/b><\/span><\/span><\/span>-3<\/b><\/span><\/span><\/sup><\/span>\u00a0 —\u00a0 n=14,4.10<\/b><\/span><\/span><\/span>-3<\/b><\/span><\/span><\/sup><\/span>\/1,6.10<\/b><\/span><\/span><\/span>-19<\/b><\/span><\/span><\/sup><\/span>\u00a0 —\u00a0 n=9.10<\/b><\/span><\/span><\/span>16<\/b><\/span><\/span><\/sup><\/span>\u00a0 —\u00a0 n=10.10<\/b><\/span><\/span><\/span>16<\/b><\/span><\/span><\/sup><\/span>\u00a0 —\u00a0 n=10<\/b><\/span><\/span><\/span>17<\/b><\/span><\/span><\/sup><\/span>\u00a0 —\u00a0<\/b><\/span><\/span><\/span>\u00a0R- A<\/b><\/span><\/span><\/span><\/p>\n

04<\/b><\/span><\/span><\/span>–<\/b><\/span><\/span><\/span> Q=\u00e1rea do tri\u00e2ngulo=b.h\/2=3.10<\/b><\/span><\/span><\/span>-3<\/b><\/span><\/span><\/sup><\/span>.4\/2\u00a0 —\u00a0 Q=6.10<\/b><\/span><\/span><\/span>-3<\/b><\/span><\/span><\/sup><\/span>C\u00a0 —<\/b><\/span><\/span><\/span>\u00a0 R- D<\/b><\/span><\/span><\/span><\/p>\n

05<\/b><\/span><\/span><\/span>–<\/b><\/span><\/span><\/span> Entre 0 e 4s\u00a0 —\u00a0 Q=\u00e1rea do ret\u00e2ngulo=b.h=4.0,4\u00a0 —\u00a0 Q=1,6C\u00a0 —\u00a0 entre 4,0s e 8,0s\u00a0 —\u00a0 Q\u2019=\u00e1rea do tri\u00e2ngulo=b.h\/2=4.0,4\/2\u00a0 —\u00a0 Q\u2019=0,8C\u00a0 —\u00a0 Q\u2019=Q\/2\u00a0 —\u00a0\u00a0<\/b><\/span><\/span><\/span>R- C<\/b><\/span><\/span><\/span><\/p>\n

06<\/b><\/span><\/span><\/span>–<\/b><\/span><\/span><\/span>\u00a0<\/b><\/span><\/span><\/span>R- A\u00a0<\/b><\/span><\/span><\/span>\u00a0—\u00a0\u00a0<\/b><\/span><\/span><\/span>Efeito Joule (efeito t\u00e9rmico)<\/b><\/span><\/span><\/span>\u00a0\u2013 Quando os el\u00e9trons livres que se movem ordenadamente no interior do condutor se chocam contra os \u00e1tomos desse material eles recebem energia e, ao receberem essa energia, vibram mais intensamente. Esse aumento vibrat\u00f3rio dos \u00e1tomos do condutor provoca um aumento de sua temperatura, liberando calor e aquecendo-o, provocando a\u00a0<\/b><\/span><\/span><\/span>transforma\u00e7\u00e3o da energia el\u00e9trica em energia t\u00e9rmica (efeito Joule)<\/b><\/span><\/span><\/span>.<\/b><\/span><\/span><\/span><\/p>\n

07<\/b><\/span><\/span><\/span><\/span>–<\/b><\/span><\/span><\/span><\/span>\u00a0<\/b><\/span><\/span><\/span><\/span>R- D<\/b><\/span><\/span><\/span>\u00a0 —\u00a0 trata-se de uma rea\u00e7\u00e3o qu\u00edmica instant\u00e2nea.<\/b><\/span><\/span><\/span><\/p>\n

08<\/b><\/span><\/span><\/span>–<\/b><\/span><\/span><\/span>\u00a0<\/b><\/span><\/span><\/span>R- D<\/b><\/span><\/span><\/span>\u00a0 —\u00a0 veja teoria<\/b><\/span><\/span><\/span><\/p>\n

09<\/b><\/span><\/span><\/span>–<\/b><\/span><\/span><\/span> R- B\u00a0 —\u00a0 Veja teoria<\/b><\/span><\/span><\/span><\/p>\n

10<\/b><\/span><\/span><\/span>–<\/b><\/span><\/span><\/span> R- B\u00a0 —\u00a0 Veja teoria<\/b><\/span><\/span><\/span><\/p>\n

11<\/b><\/span><\/span><\/span>–<\/b><\/span><\/span><\/span> Na bateria (solu\u00e7\u00e3o l\u00edquida eletrol\u00edtica) as part\u00edculas portadoras de cargas s\u00e3o os \u00edons; na l\u00e2mpada, o filamento \u00e9 um condutor s\u00f3lido e neles os portadores de cargas s\u00e3o os el\u00e9trons livres; na l\u00e2mpada fluorescente (g\u00e1s ionizado) os portadores de carga s\u00e3o os \u00edons e os el\u00e9trons\u00a0 —\u00a0<\/b><\/span><\/span><\/span>\u00a0R- A<\/b><\/span><\/span><\/span><\/p>\n

12<\/b><\/span><\/span><\/span>–<\/b><\/span><\/span><\/span> i=Q\/\u0394t=10\/10<\/b><\/span><\/span><\/span>-3<\/b><\/span><\/span><\/sup><\/span>\u00a0 —\u00a0 i=10.000A\u00a0 —\u00a0\u00a0<\/b><\/span><\/span><\/span>R- D<\/b><\/span><\/span><\/span><\/p>\n

13<\/b><\/span><\/span><\/span>–<\/b><\/span><\/span><\/span> i=Q\/\u0394 \u00a0—\u00a0 2=Q\/3.10<\/b><\/span><\/span><\/span>-3\u00a0<\/b><\/span><\/span><\/sup><\/span>\u00a0—\u00a0 Q=6.10<\/b><\/span><\/span><\/span>-3<\/b><\/span><\/span><\/sup><\/span>C\u00a0 —\u00a0 regra de tr\u00eas\u00a0 —\u00a0 1.e \u2013 1,6.10<\/b><\/span><\/span><\/span>-19<\/b><\/span><\/span><\/sup><\/span>C\u00a0 —\u00a0<\/b><\/span><\/span><\/span>\u00a0<\/b><\/span><\/span><\/span>n.e \u2013 6.10<\/b><\/span><\/span><\/span>-3<\/b><\/span><\/span><\/sup><\/span>C\u00a0 —\u00a0 1,6.10<\/b><\/span><\/span><\/span>-19<\/b><\/span><\/span><\/sup><\/span>n=6.10<\/b><\/span><\/span><\/span>-3<\/b><\/span><\/span><\/sup><\/span>\u00a0 —<\/b><\/span><\/span><\/span><\/p>\n

n=6.10-3\/1,6.10-19\u00a0 —\u00a0 n=3,75.10<\/b><\/span><\/span><\/span>16<\/b><\/span><\/span><\/sup><\/span>\u00a0part\u00edculas elementares\u00a0 —\u00a0<\/b><\/span><\/span><\/span>\u00a0R- D<\/b><\/span><\/span><\/span><\/p>\n

14<\/b><\/span><\/span><\/span>–<\/b><\/span><\/span><\/span> i=Q\/\u0394t\u00a0 —\u00a0 8.10<\/b><\/span><\/span><\/span>2<\/b><\/span><\/span><\/sup><\/span>.10<\/b><\/span><\/span><\/span>-3<\/b><\/span><\/span><\/sup><\/span>=Q\/1\u00a0 —\u00a0 Q=8.10<\/b><\/span><\/span><\/span>-1<\/b><\/span><\/span><\/sup><\/span>C\u00a0 —\u00a0 regra de tr\u00eas\u00a0 —\u00a0 1e \u2013 1,6.10<\/b><\/span><\/span><\/span>-19<\/b><\/span><\/span><\/sup><\/span>C\u00a0 —\u00a0 n.e \u2013 8.10<\/b><\/span><\/span><\/span>-1<\/b><\/span><\/span><\/sup><\/span>C\u00a0 —\u00a0 1,6.10<\/b><\/span><\/span><\/span>-19<\/b><\/span><\/span><\/sup><\/span>.n=<\/b><\/span><\/span><\/span><\/p>\n

8.10<\/b><\/span><\/span><\/span>-1<\/b><\/span><\/span><\/sup><\/span>\u00a0 —\u00a0 n=5.10<\/b><\/span><\/span><\/span>18<\/b><\/span><\/span><\/sup><\/span>\u00a0 —\u00a0<\/b><\/span><\/span><\/span>\u00a0R- C\u00a0<\/b><\/span><\/span><\/span>\u00a0<\/b><\/span><\/span><\/span><\/p>\n

15<\/b><\/span><\/span><\/span>–<\/b><\/span><\/span><\/span> Q=44,4.3600=1,598.10<\/b><\/span><\/span><\/span>5<\/b><\/span><\/span><\/sup><\/span>C\u00a0 —\u00a0 1e \u2013 1,6.10<\/b><\/span><\/span><\/span>-19<\/b><\/span><\/span><\/sup><\/span>C\u00a0 —\u00a0 ne \u2013 1,598.10<\/b><\/span><\/span><\/span>5<\/b><\/span><\/span><\/sup><\/span>C\u00a0 —\u00a0 n=10<\/b><\/span><\/span><\/span>24\u00a0<\/b><\/span><\/span><\/sup><\/span>el\u00e9trons\u00a0 —\u00a0<\/b><\/span><\/span><\/span>\u00a0R- C<\/b><\/span><\/span><\/span><\/p>\n

16<\/b><\/span><\/span><\/span>–<\/b><\/span><\/span><\/span> V=\u0394S\/\u0394t\u00a0 —\u00a0 8.10<\/b><\/span><\/span><\/span>7<\/b><\/span><\/span><\/sup><\/span>=0,5\/\u0394t\u00a0 —\u00a0 \u0394t=6,25.10<\/b><\/span><\/span><\/span>-9<\/b><\/span><\/span><\/sup><\/span>s\u00a0 —\u00a0 i=Q\/<\/b><\/span><\/span><\/span>\u0394<\/b><\/span><\/span><\/span><\/span>t\u00a0 —\u00a0 2.10<\/b><\/span><\/span><\/span>-3<\/b><\/span><\/span><\/sup><\/span>=Q\/6,25.10<\/b><\/span><\/span><\/span>-9<\/b><\/span><\/span><\/sup><\/span>\u00a0 —\u00a0 Q=1,25.10<\/b><\/span><\/span><\/span>-11<\/b><\/span><\/span><\/sup><\/span>C\u00a0 —\u00a0 regra de tr\u00eas\u00a0 —\u00a0 1e \u2013 1,6.10<\/b><\/span><\/span><\/span>-19<\/b><\/span><\/span><\/sup><\/span>C\u00a0 —\u00a0 ne \u2013 1,25.10<\/b><\/span><\/span><\/span>-11<\/b><\/span><\/span><\/sup><\/span>C\u00a0 —\u00a0 1,6.10<\/b><\/span><\/span><\/span>-19<\/b><\/span><\/span><\/sup><\/span>n=1,25.10<\/b><\/span><\/span><\/span>-11<\/b><\/span><\/span><\/sup><\/span>\u00a0 —\u00a0 n=1,25.10<\/b><\/span><\/span><\/span>-11<\/b><\/span><\/span><\/sup><\/span>\/1,6.10<\/b><\/span><\/span><\/span>-19<\/b><\/span><\/span><\/sup><\/span>\u00a0 —\u00a0 n=0,78.10<\/b><\/span><\/span><\/span>8<\/b><\/span><\/span><\/sup><\/span>=<\/b><\/span><\/span><\/span><\/p>\n

7,8.10<\/b><\/span><\/span><\/span>7<\/b><\/span><\/span><\/sup><\/span>\u00a0el\u00e9trons<\/b><\/span><\/span><\/span><\/p>\n

17<\/b><\/span><\/span><\/span>–<\/b><\/span><\/span><\/span> a) i=Q\/\u0394t\u00a0 —\u00a0 6=Q\/3.600\u00a0 —\u00a0 Q=2,16.10<\/b><\/span><\/span><\/span>4<\/b><\/span><\/span><\/sup><\/span>C<\/b><\/span><\/span><\/span><\/p>\n

b) i=Q\/\u0394t\u00a0 —\u00a0 6=Q\/20.60\u00a0 —\u00a0 Q=7,2.10<\/b><\/span><\/span><\/span>3<\/b><\/span><\/span><\/sup><\/span>C\u00a0 —\u00a0 regra de tr\u00eas\u00a0 —\u00a0\u00a0 1,1mg \u2013 1C\u00a0 —\u00a0 xmg \u2013 7,2.10<\/b><\/span><\/span><\/span>3<\/b><\/span><\/span><\/sup><\/span>C\u00a0 —\u00a0 x=7,2.10<\/b><\/span><\/span><\/span>3<\/b><\/span><\/span><\/sup><\/span>.<\/b><\/span><\/span><\/span><\/p>\n

1,1.10<\/b><\/span><\/span><\/span>-3<\/b><\/span><\/span><\/sup><\/span>\u00a0 —\u00a0<\/b><\/span><\/span><\/span>\u00a0x=7,92g<\/b><\/span><\/span><\/span><\/p>\n

18<\/b><\/span><\/span><\/span>–<\/b><\/span><\/span><\/span> Q=n.e=2.10<\/b><\/span><\/span><\/span>5<\/b><\/span><\/span><\/sup><\/span>.1,6.10<\/b><\/span><\/span><\/span>-19<\/b><\/span><\/span><\/sup><\/span>\u00a0 —\u00a0 Q=3,2.10<\/b><\/span><\/span><\/span>-14<\/b><\/span><\/span><\/sup><\/span>C\u00a0 —\u00a0 i=Q\/\u0394t=3,2.10<\/b><\/span><\/span><\/span>-14<\/b><\/span><\/span><\/sup><\/span>\/10<\/b><\/span><\/span><\/span>-3<\/b><\/span><\/span><\/sup><\/span>\u00a0 —<\/b><\/span><\/span><\/span>–\u00a0 i=3,2.10<\/b><\/span><\/span><\/span>-11<\/b><\/span><\/span><\/sup><\/span>A<\/b><\/span><\/span><\/span><\/p>\n

19<\/b><\/span><\/span><\/span>–<\/b><\/span><\/span><\/span> a) Falsa \u2013 energia el\u00e9trica em t\u00e9rmica<\/b><\/span><\/span><\/span><\/p>\n

b) Falsa \u2013 foi\u00a0<\/b><\/span><\/span><\/span>Thomas Alva Edison<\/b><\/span><\/span><\/span><\/span><\/p>\n

c) Falsa \u2013 seu ponto de fus\u00e3o \u00e9 elevado<\/b><\/span><\/span><\/span><\/p>\n

d) V=\u0394S\/\u0394t\u00a0 —\u00a0 0,1.10<\/b><\/span><\/span><\/span>-3<\/b><\/span><\/span><\/sup><\/span>=0,6\/\u0394t\u00a0 —\u00a0 \u0394t=6.000s=100min\u00a0 —\u00a0 correta<\/b><\/span><\/span><\/span><\/p>\n

e) C\/5=(F \u2013 32)\/9\u00a0 — 2500\/5=(F \u2013 32)\/9\u00a0 —\u00a0 500=(F \u2013 32)\/9\u00a0 —\u00a0 F=4500 + 32\u00a0 —<\/b><\/span><\/span><\/span><\/span>\u00a0F=4532<\/b><\/span><\/span><\/span><\/span>o<\/b><\/span><\/span><\/span><\/sup><\/span>F<\/b><\/span><\/span><\/span><\/span>—\u00a0 Falsa<\/b><\/span><\/span><\/span><\/span><\/p>\n

R- D<\/b><\/span><\/span><\/span><\/p>\n

20<\/b><\/span><\/span><\/span>–<\/b><\/span><\/span><\/span> a) E<\/b><\/span><\/span><\/span>Ctotal<\/b><\/span><\/span><\/sub><\/span>=3.10<\/b><\/span><\/span><\/span>14<\/b><\/span><\/span><\/sup><\/span>.7.10<\/b><\/span><\/span><\/span>12<\/b><\/span><\/span><\/sup><\/span>=2,1.10<\/b><\/span><\/span><\/span>27<\/b><\/span><\/span><\/sup><\/span>eV\u00a0 —\u00a0 em joules\u00a0 —\u00a0 E<\/b><\/span><\/span><\/span>Ctotal<\/b><\/span><\/span><\/sub><\/span>=2,1.10<\/b><\/span><\/span><\/span>27<\/b><\/span><\/span><\/sup><\/span>.1,6.10<\/b><\/span><\/span><\/span>-19<\/b><\/span><\/span><\/sup><\/span>\u00a0 —\u00a0<\/b><\/span><\/span><\/span>E<\/b><\/span><\/span><\/span>Ctotal<\/b><\/span><\/span><\/sub><\/span>=3,36.10<\/b><\/span><\/span><\/span>8<\/b><\/span><\/span><\/sup><\/span>J<\/b><\/span><\/span><\/span><\/p>\n

b) E<\/b><\/span><\/span><\/span>Ctotal<\/b><\/span><\/span><\/sub><\/span>=m.V<\/b><\/span><\/span><\/span>2<\/b><\/span><\/span><\/sup><\/span>\/2\u00a0 —\u00a0 3,36.10<\/b><\/span><\/span><\/span>8<\/b><\/span><\/span><\/sup><\/span>=400.10<\/b><\/span><\/span><\/span>3<\/b><\/span><\/span><\/sup><\/span>.V<\/b><\/span><\/span><\/span>2<\/b><\/span><\/span><\/sup><\/span>\/2\u00a0 —\u00a0 V=\u221a17.10<\/b><\/span><\/span><\/span>2<\/b><\/span><\/span><\/sup><\/span>\u00a0 —\u00a0\u00a0<\/b><\/span><\/span><\/span>V=41,2m\/s x 3,6=148,32km\/h<\/b><\/span><\/span><\/span><\/p>\n

c) Q<\/b><\/span><\/span><\/span>total<\/b><\/span><\/span><\/sub><\/span>=N.q=3.10<\/b><\/span><\/span><\/span>14<\/b><\/span><\/span><\/sup><\/span>.1,6.10<\/b><\/span><\/span><\/span>-19<\/b><\/span><\/span><\/sup><\/span>\u00a0 —\u00a0 Q<\/b><\/span><\/span><\/span>total<\/b><\/span><\/span><\/sub><\/span>=4,8.10<\/b><\/span><\/span><\/span>-5<\/b><\/span><\/span><\/sup><\/span>C\u00a0 —\u00a0 L=27km=27.10<\/b><\/span><\/span><\/span>3<\/b><\/span><\/span><\/sup><\/span>m\u00a0 —\u00a0 V=\u0394S\/\u0394t\u00a0 —\u00a0 c=L\/\u0394t\u00a0 —\u00a0 3.10<\/b><\/span><\/span><\/span>8<\/b><\/span><\/span><\/sup><\/span>=27.10<\/b><\/span><\/span><\/span>3<\/b><\/span><\/span><\/sup><\/span>\/\u0394t\u00a0 —\u00a0 \u0394t=27.10<\/b><\/span><\/span><\/span>3<\/b><\/span><\/span><\/sup><\/span>\/3.10<\/b><\/span><\/span><\/span>8<\/b><\/span><\/span><\/sup><\/span>\u00a0 —\u00a0 \u0394t=9.10<\/b><\/span><\/span><\/span>-5<\/b><\/span><\/span><\/sup><\/span>s\u00a0 —\u00a0 i=Q<\/b><\/span><\/span><\/span>total<\/b><\/span><\/span><\/sub><\/span>\/\u0394t=4,8.10<\/b><\/span><\/span><\/span>-5<\/b><\/span><\/span><\/sup><\/span>\/9.10<\/b><\/span><\/span><\/span>-5<\/b><\/span><\/span><\/sup><\/span>\u00a0 —\u00a0<\/b><\/span><\/span><\/span>\u00a0i=0,53A<\/b><\/span><\/span><\/span><\/p>\n

21<\/b><\/span><\/span><\/span>–<\/b><\/span><\/span><\/span> \u00a0 M\u00f3dulo da\u00a0carga dos \u00edons positivos\u00a0 —\u00a0 Q<\/b><\/span><\/span><\/span>+<\/b><\/span><\/span><\/sub><\/span>=1,0.10<\/b><\/span><\/span><\/span>18<\/b><\/span><\/span><\/sup><\/span>.1,6.10<\/b><\/span><\/span><\/span>-19<\/b><\/span><\/span><\/sup><\/span>\u00a0 —\u00a0 Q<\/b><\/span><\/span><\/span>+<\/b><\/span><\/span><\/sub><\/span>=0,16C\u00a0 —\u00a0 o m\u00f3dulo das cargas dos \u00edons negativos \u00e9 o mesmo\u00a0 —\u00a0 Q<\/b><\/span><\/span><\/span>–<\/b><\/span><\/span><\/sub><\/span>=0,16C\u00a0 —\u00a0 m\u00f3dulo da carga total\u00a0 —\u00a0 Q<\/b><\/span><\/span><\/span>total<\/b><\/span><\/span><\/sub><\/span>=\u25020,16 + 0,16\u2502=\u25020,32\u2502C\u00a0 —\u00a0 i=Q<\/b><\/span><\/span><\/span>total<\/b><\/span><\/span><\/sub><\/span>\/\u0394t\u00a0 —\u00a0<\/b><\/span><\/span><\/span><\/p>\n

I=0,32\/1\u00a0 —\u00a0 i=0,32 A\u00a0 —\u00a0<\/b><\/span><\/span><\/span>\u00a0R- B<\/b><\/span><\/span><\/span><\/p>\n

22<\/b><\/span><\/span><\/span>–<\/b><\/span><\/span><\/span> Q=n.e=10<\/b><\/span><\/span><\/span>18<\/b><\/span><\/span><\/sup><\/span>.1,6.10<\/b><\/span><\/span><\/span>-19<\/b><\/span><\/span><\/sup><\/span>\u00a0 —\u00a0 Q=1,6.10<\/b><\/span><\/span><\/span>-1<\/b><\/span><\/span><\/sup><\/span>C\u00a0 —\u00a0 i=Q\/\u0394t=0,16\/1\u00a0 —\u00a0 i=0,16 A\u00a0 —\u00a0<\/b><\/span><\/span><\/span>\u00a0R- C<\/b><\/span><\/span><\/span><\/p>\n

23<\/b><\/span><\/span><\/span>–<\/b><\/span><\/span><\/span> A primeira afirma\u00e7\u00e3o \u00e9 correta e a segunda \u00e9 falsa, pois o ar pode ser condutor conforme a terceira afirmativa\u00a0 —\u00a0 i=Q\/\u0394t\u00a0 —\u00a0 10.000=20\/\u0394t\u00a0 —\u00a0 \u0394t=20\/10.000=0,002s\u00a0 —\u00a0<\/b><\/span><\/span><\/span>\u00a0R- C<\/b><\/span><\/span><\/span><\/p>\n

24<\/b><\/span><\/span><\/span>–<\/b><\/span><\/span><\/span> i=Q\/\u0394t\u00a0 —\u00a0 300.000=Q\/0,5\u00a0 —\u00a0 Q=150.000C\u00a0 —\u00a0 fra\u00e7\u00e3o f=Q\/Q<\/b><\/span><\/span><\/span>Terra<\/b><\/span><\/span><\/sub><\/span>=150.000\/600.000\u00a0 —\u00a0 f=1\/4\u00a0 —\u00a0\u00a0<\/b><\/span><\/span><\/span>R- C<\/b><\/span><\/span><\/span><\/p>\n

25-<\/b><\/span><\/span><\/span>\u00a0a) Observe as medidas assinaladas na figura\u00a0 —\u00a0 nessa figura, voc\u00ea obt\u00e9m o di\u00e2metro do ponteiro dos segundos\u00a0 —\u00a0 \u00a0D = 58,0 mm\u00a0<\/b><\/span><\/span><\/span><\/p>\n

\"\"<\/p>\n

—\u00a0 per\u00edodo desse ponteiro\u00a0 —\u00a0\u00a0 T = 60 s\u00a0 —\u00a0 a cada volta, o espa\u00e7o percorrido pela extremidade desse ponteiro \u00e9\u00a0 —\u00a0 \u0394S = 2\u03c0R=2\u03c0D\/2\u00a0 —\u00a0 \u0394S=\u03c0D\u00a0 —\u00a0 V=\u0394S\/\u0394t=\u03c0D\/T=3×58\/60\u00a0 —\u00a0 V=174\/60\u00a0 —\u00a0\u00a0<\/b><\/span><\/span><\/span>V=2,9mm\/s<\/b><\/span><\/span><\/span><\/p>\n

b) Dados\u00a0 —\u00a0 q = 2,4 A.h = 8,64×10<\/b><\/span><\/span><\/span>3<\/b><\/span><\/span><\/sup><\/span>\u00a0C\u00a0 — \u00a0\u0394t = 400 dias = (400 x 24) h\u00a0 —\u00a0 corrente el\u00e9trica m\u00e9dia\u00a0 —\u00a0 i=q\/\u0394t=2,4\/400×24\u00a0 —\u00a0 i=0,1\/400\u00a0 —\u00a0 i=2,5.10<\/b><\/span><\/span><\/span>-4<\/b><\/span><\/span><\/sup><\/span>\u00a0A\u00a0 —\u00a0<\/b><\/span><\/span><\/span>\u00a0i=0,25mA<\/b><\/span><\/span><\/span><\/p>\n

26-<\/b><\/span><\/span><\/span>\u00a0i=\u0394Q\/\u0394t\u00a0 —\u00a0 0,3= \u0394Q\/120\u00a0 —\u00a0 \u0394Q=36C\u00a0 —\u00a0 Q=ne\u00a0 —\u00a0 36=n.1,6.10<\/b><\/span><\/span><\/span>-19<\/b><\/span><\/span><\/sup><\/span>\u00a0 —\u00a0 n=2,25.10<\/b><\/span><\/span><\/span>20<\/b><\/span><\/span><\/sup><\/span>\u00a0el\u00e9trons\u00a0 —\u00a0<\/b><\/span><\/span><\/span>\u00a0R- E<\/b><\/span><\/span><\/span><\/p>\n

27-<\/b><\/span><\/span><\/span>\u00a0Princ\u00edpio de funcionamento de uma l\u00e2mpada de filamento (l\u00e2mpada comum)\u00a0 —\u00a0 ela possui um filamento (resistor), conectado \u00e0 rede el\u00e9trica por dois pontos de contato, a rosca met\u00e1lica (parte rosqueada) e o pino inferior\u00a0 —\u00a0 para que o filamento seja<\/b><\/span><\/span><\/span><\/p>\n

\"\"<\/p>\n

\u00a0percorrido por corrente el\u00e9trica, fique incandescente e emita luz, entre esses dois pontos de contato deve existir uma diferen\u00e7a de potencial e o filamento pode dissipar energia sob forma t\u00e9rmica e principalmente luminosa\u00a0 —\u00a0 a proposta de Mateus \u00e9 falsa, pois ela n\u00e3o constitui um circuito fechado\u00a0 —\u00a0 Carlos estabeleceu um curto circuito, pois ligou os dois p\u00f3los da pilha em um \u00fanico ponto de contato (rosca met\u00e1lica)\u00a0 —\u00a0 nas montagens de Jo\u00e3o e Pedro o circuito est\u00e1 ligado corretamente entre os dois pontos de contato, o pino inferior e a parte rosqueada, estabelecendo assim, entre eles uma diferen\u00e7a de potencial, acendendo a l\u00e2mpada\u00a0 —\u00a0\u00a0<\/b><\/span><\/span><\/span>R- C<\/b><\/span><\/span><\/span><\/p>\n

28-<\/b><\/span><\/span><\/span>\u00a0<\/b><\/span><\/span><\/span>i=Q\/\u0394t\u00a0 —\u00a0 1.2.10<\/b><\/span><\/span><\/span>4<\/b><\/span><\/span><\/sup><\/span>=Q\/25.10<\/b><\/span><\/span><\/span>-6<\/b><\/span><\/span><\/sup><\/span>\u00a0 —\u00a0 Q=1.2.10<\/b><\/span><\/span><\/span>4<\/b><\/span><\/span><\/sup><\/span>.25.10<\/b><\/span><\/span><\/span>-6<\/b><\/span><\/span><\/sup><\/span>\u00a0 —\u00a0 Q=30.10<\/b><\/span><\/span><\/span>-2<\/b><\/span><\/span><\/sup><\/span>=0,3C\u00a0 —\u00a0\u00a0<\/b><\/span><\/span><\/span>R- D<\/b><\/span><\/span><\/span><\/p>\n

29-<\/b><\/span><\/span><\/span> R- B<\/b><\/span><\/span><\/span>\u00a0 —\u00a0 este fen\u00f4meno chama-se efeito Joule.<\/b><\/span><\/span><\/span><\/p>\n

30-<\/b><\/span><\/span><\/span>\u00a0<\/b><\/span><\/span><\/span>Em todo gr\u00e1fico corrente el\u00e9trica x tempo a carga el\u00e9trica Q \u00e9 numericamente igual \u00e0 \u00e1rea<\/b><\/span><\/span><\/span><\/p>\n

\"\"<\/p>\n

\u00a0compreendida entre a reta representativa e o eixo do tempo (figura)\u00a0 —\u00a0 \u00e1rea de um trap\u00e9zio\u00a0 —\u00a0 Q=(B + b).h\/2=(4 + 1).4\/2\u00a0 —\u00a0<\/b><\/span><\/span><\/span>\u00a0Q=10C<\/b><\/span><\/span><\/span><\/p>\n

31-<\/b><\/span><\/span><\/span>\u00a0i=Q\/\u0394t\u00a0 —\u00a0 2=2,16.10<\/b><\/span><\/span><\/span>5<\/b><\/span><\/span><\/sup><\/span>\/\u0394t\u00a0 —\u00a0 \u0394t=1.08.10<\/b><\/span><\/span><\/span>5<\/b><\/span><\/span><\/sup><\/span>s =1,08.10<\/b><\/span><\/span><\/span>5<\/b><\/span><\/span><\/sup><\/span>3.600\u00a0 —\u00a0 \u0394t=30h\u00a0 —\u00a0\u00a0<\/b><\/span><\/span><\/span>R- B<\/b><\/span><\/span><\/span><\/p>\n

32-<\/b><\/span><\/span><\/span>\u00a0<\/b><\/span><\/span><\/span>O1- Falsa\u00a0 —\u00a0 bateria fornece corrente cont\u00ednua e sempre com a mesma intensidade.<\/b><\/span><\/span><\/span><\/p>\n

02. Correta\u00a0 —\u00a0 o sentido convencional da corrente el\u00e9trica \u00e9 sempre contr\u00e1rio ao do movimento dos el\u00e9trons livres que saem do p\u00f3lo negativo e chegam ao positivo.<\/b><\/span><\/span><\/span><\/p>\n

04. Correta\u00a0 —\u00a0 trata-se do efeito Joule.<\/b><\/span><\/span><\/span><\/p>\n

08. Correta\u00a0 —\u00a0 el\u00e9trons tem carga negativa e o sentido do movimento (da for\u00e7a) \u00e9 contr\u00e1rio ao do campo el\u00e9trico.<\/b><\/span><\/span><\/span><\/p>\n

16- Correta\u00a0 —\u00a0 trata-se de uma corrente alternada.<\/b><\/span><\/span><\/span><\/p>\n

R- (02 + 04 + 08 + 16)=30<\/b><\/span><\/span><\/span><\/p>\n

33-<\/b><\/span><\/span><\/span>\u00a0<\/b><\/span><\/span><\/span>O gerador, por exemplo, uma pilha, transforma energia qu\u00edmica em energia el\u00e9trica, transferindo energia aos portadores de carga el\u00e9trica, no caso de fio, s\u00e3o os el\u00e9trons livres do material do fio, que se deslocam constituindo assim uma corrente el\u00e9trica\u00a0 —\u00a0\u00a0<\/b><\/span><\/span><\/span>R- D<\/b><\/span><\/span><\/span><\/p>\n

34-<\/b><\/span><\/span><\/span> R- A\u00a0<\/b><\/span><\/span><\/span>\u00a0—\u00a0 veja teoria<\/b><\/span><\/span><\/span><\/p>\n

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

35- <\/b><\/span><\/span><\/span>1 amp\u00e9re = 1 A = 1 coulomb\/segundo=1 C\/s\u00a0 —\u00a0 1h=3 600s\u00a0 —\u00a0 dado do exerc\u00edcio\u00a0 —\u00a0 Q=0,8 A.h = 0,8 C\/s.3 600s\u00a0 —\u00a0 Q=2 880C\u00a0\u00a0 —\u00a0 corrente el\u00e9trica m\u00e9dia\u00a0 —\u00a0 im=Q\/\u2206t\u00a0 —\u00a0 3,2 = 2 880\/\u2206t\u00a0 —\u00a0 \u2206t=2 880\/3,2=900s\u00a0 —\u00a0 \u2206t=900\/60=15 min\u00a0 —\u00a0\u00a0R- C\u00a0<\/b><\/span><\/span><\/p>\n

36-<\/b><\/span><\/span><\/span> I. Correta\u00a0 —\u00a0 se dois determinados metais estiverem em contato com uma solu\u00e7\u00e3o eletrol\u00edtica, surge uma tens\u00e3o el\u00e9trica entre esses dois metais e a solu\u00e7\u00e3o, originando assim uma corrente el\u00e9trica. O car\u00e1ter \u00e1cido da solu\u00e7\u00e3o ajuda na condu\u00e7\u00e3o da eletricidade.<\/b><\/span><\/span><\/span><\/p>\n

II. Correta\u00a0 —\u00a0 nos condutores met\u00e1licos a corrente el\u00e9trica consiste no movimento ordenado de el\u00e9trons livres.<\/b><\/span><\/span><\/span><\/p>\n

III. Correta\u00a0 —\u00a0 nos m\u00fasculos da r\u00e3 surge um fluxo de \u00edons que surgem um circuito formado por tr\u00eas condutores – um, eletrol\u00edtico, e dois me\u00adt\u00e1licos, que provocam sua contra\u00e7\u00e3o.<\/b><\/span><\/span><\/span><\/p>\n

R- E<\/b><\/span><\/span><\/span><\/p>\n

 <\/p>\n

Voltar para os exerc\u00edcios<\/a><\/span><\/h3>\n","protected":false},"excerpt":{"rendered":"

Resolu\u00e7\u00e3o comentada dos exerc\u00edcios de vestibulares sobre Corrente El\u00e9trica 01– Q=\u00e1rea do ret\u00e2ngulo=b.h=2.4\u00a0 —\u00a0\u00a0Q=8C 02– entre zero e 0,6s\u00a0 —\u00a0 fio 1\u00a0 —\u00a0 Q1=\u00e1rea do tri\u00e2ngulo e Q2=\u00e1rea do trap\u00e9zio\u00a0 —\u00a0 observe na s figuras abaixo que a \u00e1rea do trap\u00e9zio \u00e9 maior que a \u00e1rea do tri\u00e2ngulo, ou seja, Q2>Q1. Entre 0,6s e 1,0s\u00a0 — Q1\u2019=\u00e1rea do trap\u00e9zio da<\/p>\n","protected":false},"author":1,"featured_media":0,"parent":1683,"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-1687","page","type-page","status-publish","hentry"],"aioseo_notices":[],"_links":{"self":[{"href":"https:\/\/fisicaevestibular.com.br\/novo\/wp-json\/wp\/v2\/pages\/1687","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=1687"}],"version-history":[{"count":5,"href":"https:\/\/fisicaevestibular.com.br\/novo\/wp-json\/wp\/v2\/pages\/1687\/revisions"}],"predecessor-version":[{"id":12252,"href":"https:\/\/fisicaevestibular.com.br\/novo\/wp-json\/wp\/v2\/pages\/1687\/revisions\/12252"}],"up":[{"embeddable":true,"href":"https:\/\/fisicaevestibular.com.br\/novo\/wp-json\/wp\/v2\/pages\/1683"}],"wp:attachment":[{"href":"https:\/\/fisicaevestibular.com.br\/novo\/wp-json\/wp\/v2\/media?parent=1687"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}