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A thin film of oil (n = 1.25) is located on smooth, wet paveme

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Solving time: 3 mins

A thin film of oil $(n = 1.25)$ is located on smooth, wet pavement. When viewed perpendicular to the pavement, the film reflects the most strongly red light at 640 nm and reflects no green light at 512 nm. How thick is the oil film?

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A thin film of oil

(n = 1.25)

is located on smooth, wet pavement. When viewed perpendicular to the pavement, the film reflects the most strongly red light at 640 nm and reflects no green light at 512 nm. How thick is the oil film?

14 mins ago

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14 mins ago

Text solutionVerified

The layers are air, oil, and water. Because

1 < 1.25 < 1.33

, light reflected both from the top and from the bottom surface of the oil suffers phase reversal. For constructive interference we required

2 t = \frac{m λ _{cons}}{n}

and for destructive interference,

2 t = \frac{[ m + ( 1/2 )] λ _{des}}{n} Then, \frac{λ _{cons}}{λ _{dest}} = 1 + \frac{1}{2 m} = \frac{640 nm}{512 nm} = 1.25 and m = 2 Therefore, t = \frac{2 ( 640 nm )}{2 ( 1.25 )} = 512 nm

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Question Text	A thin film of oil $(n = 1.25)$ is located on smooth, wet pavement. When viewed perpendicular to the pavement, the film reflects the most strongly red light at 640 nm and reflects no green light at 512 nm. How thick is the oil film?
Topic	Waves
Subject	Physics
Class	Class 11
Answer Type	Text solution:1
Upvotes	147

A thin film of oil $(n = 1.25)$ is located on smooth, wet pavement. When viewed perpendicular to the pavement, the film reflects the most strongly red light at 640 nm and reflects no green light at 512 nm. How thick is the oil film?

Text solutionVerified

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A thin film of oil (n=1.25) is located on smooth, wet pavement. When viewed perpendicular to the pavement, the film reflects the most strongly red light at 640 nm and reflects no green light at 512 nm. How thick is the oil film?

Text solutionVerified

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A thin film of oil $(n = 1.25)$ is located on smooth, wet pavement. When viewed perpendicular to the pavement, the film reflects the most strongly red light at 640 nm and reflects no green light at 512 nm. How thick is the oil film?