{"id":2438,"date":"2016-09-11T00:46:00","date_gmt":"2016-09-11T00:46:00","guid":{"rendered":"http:\/\/fisicaevestibular.com.br\/novo\/?page_id=2438"},"modified":"2024-08-23T15:07:18","modified_gmt":"2024-08-23T15:07:18","slug":"interferencia-luminosa-experimento-de-young","status":"publish","type":"page","link":"https:\/\/fisicaevestibular.com.br\/novo\/ondulatoria\/ondas\/interferencia-luminosa-experimento-de-young\/","title":{"rendered":"Interfer\u00eancia Luminosa \u2013 Experimento de Young"},"content":{"rendered":"

Interfer\u00eancia Luminosa \u2013 Experimento de Young<\/b><\/span><\/span><\/span><\/p>\n

O <\/b><\/span><\/span><\/span>f\u00edsico e m\u00e9dico ingl\u00eas Thomas Young <\/b><\/span><\/span><\/span>(1773-18290), atrav\u00e9s da <\/b><\/span><\/span><\/span>experi\u00eancia descrita a seguir, demonstrou que a luz possu\u00eda natureza ondulat\u00f3ria,<\/b><\/span><\/span><\/span> pois os <\/b><\/span><\/span><\/span>fen\u00f4menos <\/b><\/span><\/span><\/span>de<\/b><\/span><\/span><\/span> <\/b>difra\u00e7\u00e3o e interfer\u00eancia<\/b><\/span><\/span><\/span> descritos nessa experi\u00eancia, s\u00e3o de <\/b><\/span><\/span><\/span>caracter\u00edsticas exclusivamente ondulat\u00f3rias.<\/b><\/span><\/span><\/span><\/p>\n

Ele fez um <\/b><\/span><\/span><\/span>pincel de luz monocrom\u00e1tica <\/b><\/span><\/span><\/span>(uma s\u00f3 cor) <\/b><\/span><\/span><\/span>incidir<\/b><\/span><\/span><\/span> sobre uma <\/b><\/span><\/span><\/span>tela opaca <\/b><\/span><\/span><\/span>(obst\u00e1culo) <\/b><\/span><\/span><\/span>A<\/b><\/span><\/span><\/span>, <\/b><\/span><\/span><\/span>com uma <\/b><\/span><\/span><\/span>estreita fenda <\/b><\/span><\/span><\/span>S<\/b><\/span><\/span><\/span>o<\/b><\/span><\/span><\/sub><\/span>. <\/b><\/span><\/span><\/span><\/p>\n

A <\/b><\/span><\/span><\/span>luz que atinge essa fenda S<\/b><\/span><\/span><\/span>o<\/b><\/span><\/span><\/sub><\/span> <\/b>se <\/b><\/span><\/span><\/span>espalha sofrendo difra\u00e7\u00e3o (<\/b><\/span><\/span><\/span>fen\u00f4meno<\/b><\/span><\/span><\/span> que <\/b><\/span><\/span><\/span>permite<\/b><\/span><\/span><\/span> com que uma <\/b><\/span><\/span><\/span>onda atravesse fendas ou contorne obst\u00e1culos, atingindo regi\u00f5es <\/b><\/span><\/span><\/span>onde, segundo a <\/b><\/span><\/span><\/span>propaga\u00e7\u00e3o retil\u00ednea da luz, n\u00e3o conseguiria chegar).<\/b><\/span><\/span><\/span> \u00a0<\/b><\/span><\/span><\/span><\/p>\n

Atr\u00e1s<\/b><\/span><\/span><\/span> da <\/b><\/span><\/span><\/span>primeira tela, <\/b><\/span><\/span><\/span>ele colocou <\/b><\/span><\/span><\/span>outra tela opaca <\/b><\/span><\/span><\/span>B<\/b><\/span><\/span><\/span>, <\/b><\/span><\/span><\/span>com <\/b><\/span><\/span><\/span>duas<\/b><\/span><\/span><\/span> fendas muito estreitas <\/b><\/span><\/span><\/span>e <\/b><\/span><\/span><\/span>convenientemente pr\u00f3ximas (<\/b><\/span><\/span><\/span>S<\/b><\/span><\/span><\/span>1<\/b><\/span><\/span><\/sub><\/span>\u00a0e S<\/b><\/span><\/span><\/span>2<\/b><\/span><\/span><\/sub><\/span>), <\/b><\/span><\/span><\/span>sendo que <\/b><\/span><\/span><\/span>cada uma delas funciona como uma fonte prim\u00e1ria de ondas exatamente iguais <\/b><\/span><\/span><\/span>(mesma frequ\u00eancia, mesmo comprimento de onda, mesma velocidade e <\/b><\/span><\/span><\/span><\/p>\n

\"\"<\/p>\n

\"\"<\/p>\n

em fase), ou seja, <\/b><\/span><\/span><\/span>ondas coerentes,<\/b><\/span><\/span><\/span> que \u00e9 <\/b><\/span><\/span><\/span>condi\u00e7\u00e3o necess\u00e1ria para que ocorra a interfer\u00eancia.<\/b><\/span><\/span><\/span><\/p>\n

Em seguida, a <\/b><\/span><\/span><\/span>uma dist\u00e2ncia D do obst\u00e1culo B<\/b><\/span><\/span><\/span> ele colocou\u00a0 um <\/b><\/span><\/span><\/span>anteparo<\/b><\/span><\/span><\/span> (alvo, pel\u00edcula fotogr\u00e1fica) <\/b><\/span><\/span><\/span>C<\/b><\/span><\/span><\/span>, de tal modo que a <\/b><\/span><\/span><\/span>separa\u00e7\u00e3o d entre as fendas S<\/b><\/span><\/span><\/span>1<\/b><\/span><\/span><\/sub><\/span>\u00a0e S<\/b><\/span><\/span><\/span>2<\/b><\/span><\/span><\/sub><\/span>\u00a0\u00e9 muito menor que a dist\u00e2ncia\u00a0 entre o obst\u00e1culo B e a tela C.<\/b><\/span><\/span><\/span><\/p>\n

Ent\u00e3o ele <\/b><\/span><\/span><\/span>observou na tela C <\/b><\/span><\/span><\/span>uma <\/b><\/span><\/span><\/span>figura de interfer\u00eancia <\/b><\/span><\/span><\/span>formada por <\/b><\/span><\/span><\/span>franjas brilhantes coloridas <\/b><\/span><\/span><\/span>(interfer\u00eancia construtiva) <\/b><\/span><\/span><\/span>alternadas por franjas escuras <\/b><\/span><\/span><\/span>(interfer\u00eancia destrutiva).<\/b><\/span><\/span><\/span><\/p>\n

\"\"<\/p>\n

Atualmente<\/b><\/span><\/span><\/span> na <\/b><\/span><\/span><\/span>experi\u00eancia de Young <\/b><\/span><\/span><\/span>voc\u00ea pode substituir o <\/b><\/span><\/span><\/span>anteparo A (fonte de luz) por um laser (veja figura),<\/b><\/span><\/span><\/span> pois ele <\/b><\/span><\/span><\/span>converte luz comum em um feixe intenso e fino.<\/b><\/span><\/span><\/span><\/p>\n

O <\/b><\/span><\/span><\/span>padr\u00e3o de faixas de faixas de luz <\/b><\/span><\/span><\/span>projetado na tela \u00e9 chamado <\/b><\/span><\/span><\/span>franjas de interfer\u00eancia.<\/b><\/span><\/span><\/span><\/p>\n

Se a <\/b><\/span><\/span><\/span>luz incidente for luz monocrom\u00e1tica vermelha <\/b><\/span><\/span><\/span>as <\/b><\/span><\/span><\/span>franjas ser\u00e3o vermelho-escuro, <\/b><\/span><\/span><\/span>se <\/b><\/span><\/span><\/span>verde, verde-escuro, <\/b><\/span><\/span><\/span>se <\/b><\/span><\/span><\/span>policrom\u00e1tica branca, teremos uma faixa central branca, resultado da interfer\u00eancia construtiva para todas as cores<\/b><\/span><\/span><\/span> e as <\/b><\/span><\/span><\/span>demais fixas ser\u00e3o coloridas (interfer\u00eancia construtiva para algumas cores e destrutiva para outras).<\/b><\/span><\/span><\/span><\/p>\n

\"\"<\/p>\n

A dist\u00e2ncia <\/b><\/span><\/span><\/span>d<\/b><\/span><\/span><\/span> <\/b>entre as fendas <\/b><\/span><\/span><\/span>influi no padr\u00e3o das franjas.<\/b><\/span><\/span><\/span><\/p>\n

Express\u00f5es matem\u00e1ticas que envolvem o experimento de Young<\/b><\/span><\/span><\/span><\/p>\n

Vamos chamar <\/b><\/span><\/span><\/span>de <\/b><\/span><\/span><\/span>d<\/b><\/span><\/span><\/span> a dist\u00e2ncia entre as fendas S<\/b><\/span><\/span><\/span>1<\/b><\/span><\/span><\/sub><\/span>\u00a0e S<\/b><\/span><\/span><\/span>2<\/b><\/span><\/span><\/sub><\/span>\u00a0e de <\/b><\/span><\/span><\/span>D<\/b><\/span><\/span><\/span> a dist\u00e2ncia entre o obst\u00e1culo B e o anteparo C.<\/b><\/span><\/span><\/span><\/p>\n

No <\/b><\/span><\/span><\/span>anteparo C, em O, temos a franja central. <\/b><\/span><\/span><\/span>\"\"<\/p>\n

Um <\/b><\/span><\/span><\/span>ponto qualquer P, distante Y da franja central, sobre o anteparo C <\/b><\/span><\/span><\/span>ser\u00e1 <\/b><\/span><\/span><\/span>sede de interfer\u00eancia construtiva apresentando-se como um ponto claro ou brilhante <\/b><\/span><\/span><\/span>(com intensidade luminosa m\u00e1xima), se a <\/b><\/span><\/span><\/span>diferen\u00e7a de caminhos r<\/b><\/span><\/span><\/span>1 <\/b><\/span><\/span><\/sub><\/span>– r<\/b><\/span><\/span><\/span>2<\/b><\/span><\/span><\/sub><\/span>\u00a0for um m\u00faltiplo par de meio comprimento de onda, ou seja, r<\/b><\/span><\/span><\/span>1 <\/b><\/span><\/span><\/sub><\/span>-r<\/b><\/span><\/span><\/span>2 <\/b><\/span><\/span><\/sub><\/span>= n(\u03bb\/2), com (n = 0, 2, 4, 6 …)<\/b><\/span><\/span><\/span><\/p>\n

Observe que a <\/b><\/span><\/span><\/span>franja localizada na regi\u00e3o central ser\u00e1 sempre clara, <\/b><\/span><\/span><\/span>pois em <\/b><\/span><\/span><\/span>O a diferen\u00e7a <\/b><\/span><\/span><\/span>de <\/b><\/span><\/span><\/span>caminhos percorridos pelas ondas provenientes de S<\/b><\/span><\/span><\/span>1<\/b><\/span><\/span><\/sub><\/span>\u00a0e S<\/b><\/span><\/span><\/span>2<\/b><\/span><\/span><\/sub><\/span>\u00a0\u00e9 nula (r<\/b><\/span><\/span><\/span>1 <\/b><\/span><\/span><\/sub><\/span>– r<\/b><\/span><\/span><\/span>2 <\/b><\/span><\/span><\/sub><\/span>= 0). <\/b><\/span><\/span><\/span>Ent\u00e3o em <\/b><\/span><\/span><\/span>O ocorre sempre interfer\u00eancia construtiva.<\/b><\/span><\/span><\/span><\/p>\n

Em P, <\/b><\/span><\/span><\/span>teremos <\/b><\/span><\/span><\/span>interfer\u00eancia destrutiva <\/b><\/span><\/span><\/span>(franjas escuras), se <\/b><\/span><\/span><\/span>r<\/b><\/span><\/span><\/span>1 <\/b><\/span><\/span><\/sub><\/span>– r<\/b><\/span><\/span><\/span>2\u00a0<\/b><\/span><\/span><\/sub><\/span>for m\u00faltiplo \u00edmpar de meio comprimento de onda, <\/b><\/span><\/span><\/span>ou seja<\/b><\/span><\/span><\/span>, r<\/b><\/span><\/span><\/span>1 <\/b><\/span><\/span><\/sub><\/span>– r<\/b><\/span><\/span><\/span>2 <\/b><\/span><\/span><\/sub><\/span>= n(\u03bb\/2), com (n = 1, 3, 5, 7…).<\/b><\/span><\/span><\/span><\/p>\n

Em <\/b><\/span><\/span><\/span>torno <\/b><\/span><\/span><\/span>da regi\u00e3o central <\/b><\/span><\/span><\/span>obtemos alternadamente franjas claras e escuras. <\/b><\/span><\/span><\/span><\/p>\n

Ao lado est\u00e3o a <\/b><\/span><\/span><\/span>figura e a express\u00e3o matem\u00e1tica <\/b><\/span><\/span><\/span>que fornece o <\/b><\/span><\/span><\/span>comprimento de onda da luz utilizada no experimento de Young, onde:<\/b><\/span><\/span><\/span><\/p>\n

\"\"\"\"<\/p>\n

\u03bb\u00a0<\/b><\/span><\/span><\/span> —\u00a0 <\/b><\/span><\/span><\/span>comprimento de onda<\/b><\/span><\/span><\/span><\/p>\n

d<\/b><\/span><\/span><\/span>\u00a0 —\u00a0 <\/b><\/span><\/span><\/span>dist\u00e2ncia<\/b><\/span><\/span><\/span> entre as <\/b><\/span><\/span><\/span>duas fendas (fontes)<\/b><\/span><\/span><\/span><\/p>\n

D<\/b><\/span><\/span><\/span>\u00a0 — <\/b><\/span><\/span><\/span>dist\u00e2ncia <\/b><\/span><\/span><\/span>entre os <\/b><\/span><\/span><\/span>dois anteparos<\/b><\/span><\/span><\/span><\/p>\n

n<\/b><\/span><\/span><\/span>\u00a0 —\u00a0 <\/b><\/span><\/span><\/span>n\u00famero<\/b><\/span><\/span><\/span> de ordem da <\/b><\/span><\/span><\/span>interfer\u00eancia, <\/b><\/span><\/span><\/span>podendo ser <\/b><\/span><\/span><\/span>par ou \u00edmpar conforme a interfer\u00eancia seja construtiva (franja clara) ou destrutiva (franja escura).<\/b><\/span><\/span><\/span><\/p>\n

y<\/b><\/span><\/span><\/span>\u00a0 —\u00a0 <\/b><\/span><\/span><\/span>dist\u00e2ncia <\/b><\/span><\/span><\/span>de onde <\/b><\/span><\/span><\/span>ocorre a interfer\u00eancia <\/b><\/span><\/span><\/span>(no caso, <\/b><\/span><\/span><\/span>ponto P<\/b><\/span><\/span><\/span>), at\u00e9 a <\/b><\/span><\/span><\/span>franja central no ponto O.<\/b><\/span><\/span><\/span><\/p>\n

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

\"\" O <\/b><\/span><\/span><\/span>tamanho das fendas <\/b><\/span><\/span><\/span>est\u00e1 relacionado com a <\/b><\/span><\/span><\/span>defini\u00e7\u00e3o das franjas. <\/b><\/span><\/span><\/span><\/p>\n

Quando as <\/b><\/span><\/span><\/span>fendas aumentam <\/b><\/span><\/span><\/span>temos <\/b><\/span><\/span><\/span>franjas menos definidas <\/b><\/span><\/span><\/span>e <\/b><\/span><\/span><\/span>quando diminuem, mais definidas.<\/b><\/span><\/span><\/span><\/p>\n

\"\" Devido \u00e0 <\/b><\/span><\/span><\/span>reflex\u00e3o em suas superf\u00edcies internas e externas <\/b><\/span><\/span><\/span>podemos ver <\/b><\/span><\/span><\/span>manchas coloridas<\/b><\/span><\/span><\/span>\"\"<\/p>\n

(franjas de interfer\u00eancia) <\/b><\/span><\/span><\/span>em po\u00e7as de \u00e1gua quando elas tiverem em sua superf\u00edcie externa, \u00f3leo.<\/b><\/span><\/span><\/span><\/p>\n

Essa <\/b><\/span><\/span><\/span>interfer\u00eancia <\/b><\/span><\/span><\/span>entre as ondas refletidas <\/b><\/span><\/span><\/span>ocorre porque a <\/b><\/span><\/span><\/span>dist\u00e2ncia entre a superf\u00edcie anterior e posterior da pel\u00edcula \u00e9 muito pequena.<\/b><\/span><\/span><\/span><\/p>\n

O mesmo acontece com as bolhas de sab\u00e3o.<\/b><\/span><\/span><\/span><\/p>\n

O que voc\u00ea deve saber, informa\u00e7\u00f5es e dicas<\/b><\/span><\/span><\/span><\/p>\n

\"\"<\/p>\n

Conhecer <\/b><\/span><\/span><\/span>todo o <\/b><\/span><\/span><\/span>procedimento da experi\u00eancia de Young, demonstrada acima.<\/b><\/span><\/span><\/span><\/p>\n

\"\"<\/p>\n

\"\"<\/p>\n

\"\"<\/p>\n

A <\/b><\/span><\/span><\/span>experi\u00eancia de <\/b><\/span><\/span><\/span>Thomas Young<\/b><\/span><\/span><\/span> foi <\/b><\/span><\/span><\/span>muito importante, <\/b><\/span><\/span><\/span>pois foi o <\/b><\/span><\/span><\/span>primeiro a demonstrar<\/b><\/span><\/span><\/span>, com s\u00f3lidos <\/b><\/span><\/span><\/span>resultados experimentais, o fen\u00f4meno de <\/b><\/span><\/span><\/span>interfer\u00eancia luminos<\/b><\/span><\/span><\/span>a, <\/b><\/span><\/span><\/span>que tem por <\/b><\/span><\/span><\/span>consequ\u00eancia a aceita\u00e7\u00e3o da teoria ondulat\u00f3ria.<\/b><\/span><\/span><\/span><\/p>\n

Atualmente, a <\/b><\/span><\/span><\/span>teoria aceita \u00e9 a dualidade onda-part\u00edcula, enunciada<\/b><\/span><\/span><\/span> pelo f\u00edsico franc\u00eas <\/b><\/span><\/span><\/span>Louis-Victor de Broglie, <\/b><\/span><\/span><\/span>baseado nas <\/b><\/span><\/span><\/span>conclus\u00f5es sobre as caracter\u00edsticas dos f\u00f3tons, de Albert Einstein.<\/b><\/span><\/span><\/span><\/p>\n

\"\"<\/p>\n

Ao lado est\u00e3o a <\/b><\/span><\/span><\/span>figura e a express\u00e3o matem\u00e1tica <\/b><\/span><\/span><\/span>que fornece o <\/b><\/span><\/span><\/span>comprimento de onda da luz utilizada no experimento de Young, onde:<\/b><\/span><\/span><\/span>\"\"<\/p>\n

\"\"<\/p>\n

\u03bb\u00a0<\/b><\/span><\/span><\/span> —\u00a0 <\/b><\/span><\/span><\/span>comprimento de onda<\/b><\/span><\/span><\/span><\/p>\n

d<\/b><\/span><\/span><\/span>\u00a0 —\u00a0 <\/b><\/span><\/span><\/span>dist\u00e2ncia<\/b><\/span><\/span><\/span> entre as <\/b><\/span><\/span><\/span>duas fendas (fontes)<\/b><\/span><\/span><\/span><\/p>\n

D<\/b><\/span><\/span><\/span>\u00a0 — <\/b><\/span><\/span><\/span>dist\u00e2ncia <\/b><\/span><\/span><\/span>entre os <\/b><\/span><\/span><\/span>dois anteparos<\/b><\/span><\/span><\/span><\/p>\n

n<\/b><\/span><\/span><\/span>\u00a0 —\u00a0 <\/b><\/span><\/span><\/span>n\u00famero<\/b><\/span><\/span><\/span> de ordem da <\/b><\/span><\/span><\/span>interfer\u00eancia, <\/b><\/span><\/span><\/span>podendo ser <\/b><\/span><\/span><\/span>par ou \u00edmpar conforme a interfer\u00eancia seja construtiva (franja clara) ou destrutiva (franja escura).<\/b><\/span><\/span><\/span><\/p>\n

y<\/b><\/span><\/span><\/span>\u00a0 —\u00a0 <\/b><\/span><\/span><\/span>dist\u00e2ncia <\/b><\/span><\/span><\/span>de onde <\/b><\/span><\/span><\/span>ocorre a interfer\u00eancia <\/b><\/span><\/span><\/span>(no caso, <\/b><\/span><\/span><\/span>ponto P<\/b><\/span><\/span><\/span>), at\u00e9 a <\/b><\/span><\/span><\/span>franja central no ponto O.<\/b><\/span><\/span><\/span><\/p>\n

\"\"<\/p>\n

Se a <\/b><\/span><\/span><\/span>luz incidente for luz monocrom\u00e1tica vermelha <\/b><\/span><\/span><\/span>as <\/b><\/span><\/span><\/span>franjas ser\u00e3o vermelho-escu<\/b><\/span><\/span><\/span>ro, se <\/b><\/span><\/span><\/span>verde,<\/b><\/span><\/span><\/span> <\/b>verde-escuro, <\/b><\/span><\/span><\/span>se <\/b><\/span><\/span><\/span>policrom\u00e1tica branca, teremos uma faixa central branca, resultado da interfer\u00eancia construtiva para todas as cores e as demais fixas ser\u00e3o coloridas (interfer\u00eancia construtiva para algumas cores e destrutiva para outras).<\/b><\/span><\/span><\/span><\/p>\n

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

O <\/b><\/span><\/span><\/span>tamanho das fendas <\/b><\/span><\/span><\/span>est\u00e1 relacionado com a <\/b><\/span><\/span><\/span>defini\u00e7\u00e3o das franjas. <\/b><\/span><\/span><\/span><\/p>\n

Quando as <\/b><\/span><\/span><\/span>fendas aumentam temos franjas menos definidas e quando diminuem, mais definidas.<\/b><\/span><\/span><\/span><\/p>\n

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

\"\"<\/p>\n

Devido \u00e0 <\/b><\/span><\/span><\/span>reflex\u00e3o em suas superf\u00edcies internas e externas <\/b><\/span><\/span><\/span>podemos ver <\/b><\/span><\/span><\/span>manchas coloridas<\/b><\/span><\/span><\/span>\"\"<\/p>\n

(franjas de interfer\u00eancia) <\/b><\/span><\/span><\/span>em po\u00e7as de \u00e1gua quando elas tiverem em sua superf\u00edcie externa, \u00f3leo.<\/b><\/span><\/span><\/span><\/p>\n

Essa <\/b><\/span><\/span><\/span>interfer\u00eancia e<\/b><\/span><\/span><\/span>ntre as ondas refletidas <\/b><\/span><\/span><\/span>ocorre porque a <\/b><\/span><\/span><\/span>dist\u00e2ncia entre a superf\u00edcie anterior e posterior da pel\u00edcula \u00e9 muito pequena.<\/b><\/span><\/span><\/span><\/p>\n

\"\"<\/p>\n

Confira as resolu\u00e7\u00f5es desses dois exerc\u00edcios para que voc\u00ea aprenda a utilizar as f\u00f3rmulas do experimento de Young:<\/b><\/span><\/span><\/span><\/p>\n

01-(UECE)<\/b><\/span><\/span><\/span> <\/b>Uma <\/b><\/span><\/span><\/span>experi\u00eancia de interfer\u00eancia de fenda dupla<\/b><\/span><\/span><\/span> \u00e9 realizada com <\/b><\/span><\/span><\/span>luz azul-esverdeada <\/b><\/span><\/span><\/span>de <\/b><\/span><\/span><\/span>comprimento de onda igual a 512 nm. <\/b><\/span><\/span><\/span><\/p>\n

As <\/b><\/span><\/span><\/span>fendas est\u00e3o separadas, entre si, <\/b><\/span><\/span><\/span>por uma <\/b><\/span><\/span><\/span>dist\u00e2ncia de 1,2 mm. <\/b><\/span><\/span><\/span>Uma <\/b><\/span><\/span><\/span>tela \u00e9 localizada <\/b><\/span><\/span><\/span>a uma <\/b><\/span><\/span><\/span>dist\u00e2ncia de 5,4 m do anteparo que cont\u00e9m as fendas. Calcule <\/b><\/span><\/span><\/span>a <\/b><\/span><\/span><\/span>dist\u00e2ncia, em mil\u00edmetros, <\/b><\/span><\/span><\/span>que <\/b><\/span><\/span><\/span>separa <\/b><\/span><\/span><\/span>as <\/b><\/span><\/span><\/span>franjas brilhantes consecutivas vistas sobre a tela. <\/b><\/span><\/span><\/span><\/p>\n

Resolu\u00e7\u00e3o:<\/b><\/span><\/span><\/span><\/p>\n

S\u00e3o dados<\/b><\/span><\/span><\/span>:<\/b><\/span><\/span><\/span>\"\"<\/p>\n

\"\" = 512nm <\/b><\/span><\/span><\/span><\/span>= 512.10<\/b><\/span><\/span><\/span><\/span>-9<\/b><\/span><\/span><\/span><\/sup><\/span> m<\/b><\/span><\/span><\/span><\/span><\/p>\n

d<\/b><\/span><\/span><\/span><\/span> = 1, 2 mm <\/b><\/span><\/span><\/span><\/span>= 1, 2.10<\/b><\/span><\/span><\/span><\/span>-3<\/b><\/span><\/span><\/span><\/sup><\/span> m<\/b><\/span><\/span><\/span><\/span><\/p>\n

D = 5, 4 m<\/b><\/span><\/span><\/span><\/span><\/p>\n

y = ?<\/b><\/span><\/span><\/span><\/span><\/p>\n

\"\" \"\"<\/span> se as <\/b><\/span><\/span><\/span>duas franjas consecutivas <\/b><\/span><\/span><\/span>s\u00e3o <\/b><\/span><\/span><\/span>brilhantes<\/b><\/span><\/span><\/span> a <\/b><\/span><\/span><\/span>interfer\u00eancia \u00e9 construtiva<\/b><\/span><\/span><\/span> e <\/b><\/span><\/span><\/span>n \u00e9 par.<\/b><\/span><\/span><\/span><\/p>\n

Tomando, por exemplo, a <\/b><\/span><\/span><\/span>franja central e a primeira <\/b><\/span><\/span><\/span>(consecutivas) <\/b><\/span><\/span><\/span>n ser\u00e1 igual a 2 \"\" n = 2.<\/b><\/span><\/span><\/span><\/p>\n

512.10<\/b><\/span><\/span><\/span><\/span>-9<\/b><\/span><\/span><\/span><\/sup><\/span> = 2.1,2.10<\/b><\/span><\/span><\/span><\/span>-3<\/b><\/span><\/span><\/span><\/sup><\/span>.y\/2.5,4 \"\"<\/b><\/span><\/span><\/span><\/span> 5 529,6.10<\/b><\/span><\/span><\/span><\/span>-9<\/b><\/span><\/span><\/span><\/sup><\/span> = 2,4.10<\/b><\/span><\/span><\/span><\/span>-3<\/b><\/span><\/span><\/span><\/sup><\/span>y \"\" y = 5 529,6.10<\/b><\/span><\/span><\/span><\/span>-9<\/b><\/span><\/span><\/span><\/sup><\/span>\/2,4.10<\/b><\/span><\/span><\/span><\/span>-3<\/b><\/span><\/span><\/span><\/sup><\/span> \"\" <\/b><\/span><\/span><\/span><\/span>y = 2304.10<\/b><\/span><\/span><\/span><\/span>-6<\/b><\/span><\/span><\/span><\/sup><\/span> m <\/b><\/span><\/span><\/span><\/span>= 2304.10<\/b><\/span><\/span><\/span><\/span>-3<\/b><\/span><\/span><\/span><\/sup><\/span> mm \"\" <\/b><\/span><\/span><\/span><\/span>y = 2,304 mm.<\/b><\/span><\/span><\/span><\/span><\/p>\n

02-(UF-BA)<\/b><\/span><\/span><\/span> <\/b>Na <\/b><\/span><\/span><\/span>experi\u00eancia de Thomas Young, <\/b><\/span><\/span><\/span>a <\/b><\/span><\/span><\/span>luz monocrom\u00e1tica <\/b><\/span><\/span><\/span>difratada pelas <\/b><\/span><\/span><\/span>fendas F<\/b><\/span><\/span><\/span>1 <\/b><\/span><\/span><\/sub><\/span>e F<\/b><\/span><\/span><\/span>2<\/b><\/span><\/span><\/sub><\/span>\u00a0<\/b><\/span><\/span><\/span>se <\/b><\/span><\/span><\/span>superp\u00f5e <\/b><\/span><\/span><\/span>na <\/b><\/span><\/span><\/span>regi\u00e3o<\/b><\/span><\/span><\/span> limitada pelos <\/b><\/span><\/span><\/span>anteparos A<\/b><\/span><\/span><\/span>2<\/b><\/span><\/span><\/sub><\/span>\u00a0e A<\/b><\/span><\/span><\/span>3<\/b><\/span><\/span><\/sub><\/span>, <\/b><\/span><\/span><\/span>produzindo o <\/b><\/span><\/span><\/span>padr\u00e3o de interfer\u00eancia mostrado na figura.<\/b><\/span><\/span><\/span>\"\"<\/p>\n

Sabendo que a <\/b><\/span><\/span><\/span>luz utilizada<\/b><\/span><\/span><\/span> tem <\/b><\/span><\/span><\/span>freq\u00fc\u00eancia igual a 6,0.10<\/b><\/span><\/span><\/span>14<\/b><\/span><\/span><\/sup><\/span>Hz <\/b><\/span><\/span><\/span>e se <\/b><\/span><\/span><\/span>propaga<\/b><\/span><\/span><\/span> com <\/b><\/span><\/span><\/span>velocidade <\/b><\/span><\/span><\/span>de m\u00f3dulo igual a <\/b><\/span><\/span><\/span>3,0.10<\/b><\/span><\/span><\/span>8<\/b><\/span><\/span><\/sup><\/span>m\/s, <\/b><\/span><\/span><\/span>determine, em <\/b><\/span><\/span><\/span>unidades do SI, <\/b><\/span><\/span><\/span>a <\/b><\/span><\/span><\/span>diferen\u00e7a entre os percursos \u00f3pticos, a e b, <\/b><\/span><\/span><\/span>dos <\/b><\/span><\/span><\/span>raios que partem de F<\/b><\/span><\/span><\/span>1<\/b><\/span><\/span><\/sub><\/span>\u00a0e F<\/b><\/span><\/span><\/span>2<\/b><\/span><\/span><\/sub><\/span>\u00a0e atingem o ponto P.<\/b><\/span><\/span><\/span><\/p>\n

Resolu\u00e7\u00e3o:<\/b><\/span><\/span><\/span><\/p>\n

C\u00e1lculo do comprimento de onda\u00a0\"\"\u00a0 \"\"<\/b><\/span><\/span><\/span>\u00a0 <\/b><\/span><\/span><\/span>V=\"\"f\u00a0 \"\"<\/b><\/span><\/span><\/span>\u00a0 3.10<\/b><\/span><\/span><\/span>8<\/b><\/span><\/span><\/sup><\/span>=\"\" 6.10<\/b><\/span><\/span><\/span>14\u00a0\u00a0\"\"<\/b><\/span><\/span><\/sup><\/span>\u00a0\"\"<\/b><\/span><\/span><\/span> =5.10<\/b><\/span><\/span><\/span>-7<\/b><\/span><\/span><\/sup><\/span>m.<\/b><\/span><\/span><\/span><\/p>\n

A <\/b><\/span><\/span><\/span>diferen\u00e7a entre os percursos a e b <\/b><\/span><\/span><\/span>\u00e9 dada por <\/b><\/span><\/span><\/span>b \u2013 a = n.(\u03bb\/2).<\/b><\/span><\/span><\/span><\/p>\n

Mas, <\/b><\/span><\/span><\/span>n \u00e9 \u00edmpar, <\/b><\/span><\/span><\/span>pois <\/b><\/span><\/span><\/span>em P temos interfer\u00eancia destrutiva <\/b><\/span><\/span><\/span>e <\/b><\/span><\/span><\/span>n = 3 (<\/b><\/span><\/span><\/span>veja na <\/b><\/span><\/span><\/span>figura, <\/b><\/span><\/span><\/span>que \u00e9 a <\/b><\/span><\/span><\/span>segunda interfer\u00eancia destrutiva)<\/b><\/span><\/span><\/span>\u00a0 \"\"\u00a0 b \u2013 a = 3.(5.10<\/b><\/span><\/span><\/span>-7<\/b><\/span><\/span><\/sup><\/span>\/2) \u00a0\"\" \u00a0\u00a0<\/b><\/span><\/span><\/span>b \u2013 a = 7,5.10<\/b><\/span><\/span><\/span>-7 <\/b><\/span><\/span><\/sup><\/span>m.\u00a0\u00a0\u00a0<\/b><\/span><\/span><\/span><\/p>\n

 <\/p>\n

Confira os exerc\u00edcios com resolu\u00e7\u00f5es comentadas<\/span><\/a><\/h3>\n","protected":false},"excerpt":{"rendered":"

Interfer\u00eancia Luminosa \u2013 Experimento de Young O f\u00edsico e m\u00e9dico ingl\u00eas Thomas Young (1773-18290), atrav\u00e9s da experi\u00eancia descrita a seguir, demonstrou que a luz possu\u00eda natureza ondulat\u00f3ria, pois os fen\u00f4menos de difra\u00e7\u00e3o e interfer\u00eancia descritos nessa experi\u00eancia, s\u00e3o de caracter\u00edsticas exclusivamente ondulat\u00f3rias. Ele fez um pincel de luz monocrom\u00e1tica (uma s\u00f3 cor) incidir sobre uma tela opaca (obst\u00e1culo) A, com<\/p>\n","protected":false},"author":1,"featured_media":0,"parent":2398,"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-2438","page","type-page","status-publish","hentry"],"aioseo_notices":[],"_links":{"self":[{"href":"https:\/\/fisicaevestibular.com.br\/novo\/wp-json\/wp\/v2\/pages\/2438","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=2438"}],"version-history":[{"count":2,"href":"https:\/\/fisicaevestibular.com.br\/novo\/wp-json\/wp\/v2\/pages\/2438\/revisions"}],"predecessor-version":[{"id":2446,"href":"https:\/\/fisicaevestibular.com.br\/novo\/wp-json\/wp\/v2\/pages\/2438\/revisions\/2446"}],"up":[{"embeddable":true,"href":"https:\/\/fisicaevestibular.com.br\/novo\/wp-json\/wp\/v2\/pages\/2398"}],"wp:attachment":[{"href":"https:\/\/fisicaevestibular.com.br\/novo\/wp-json\/wp\/v2\/media?parent=2438"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}