Newton's Rings using refractive index of water

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Discussion Overview

The discussion revolves around the observation of Newton's Rings when using water as the medium instead of air. Participants explore the effects of changing the refractive index on the visibility and characteristics of the rings, focusing on experimental setup and light behavior.

Discussion Character

  • Exploratory
  • Technical explanation
  • Debate/contested

Main Points Raised

  • One participant notes that the rings are faint and seeks potential causes or solutions.
  • Another participant asks for more details about the experimental setup, specifically the refractive index used and the arrangement of the water between surfaces.
  • A participant explains that replacing air with water decreases the intensity of reflected light due to the reduced difference in refractive indices, which may affect visibility.
  • It is mentioned that using water, which slows down light, could result in more closely spaced rings, making them harder to observe.

Areas of Agreement / Disagreement

Participants express varying views on the effects of using water versus air, with some agreeing on the impact of refractive index on light intensity and visibility of the rings, while others seek clarification and further details about the experimental conditions. The discussion remains unresolved regarding the specific causes of the faintness of the rings.

Contextual Notes

Limitations include the lack of detailed measurements and specific values for refractive indices, as well as the potential influence of experimental setup factors such as angle and light source.

emmalou
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Hi

I am currently looking at Newtons Rings, i have changed my refractive index to water (distilled), i have found the rings and they seem to be as aspected except they are extremely faint barely readable infact would anyone know a cause or soulation to this?
 
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It's hard to say without more detail of your experiment.
What index did you changed to water? Or of what?
Did you put water between the curved surface and the plane surface?
 
nasu said:
It's hard to say without more detail of your experiment.
What index did you changed to water? Or of what?
Did you put water between the curved surface and the plane surface?

i changed the index from air to water to see the affects, yes i did byt it between the curved surface and the plane surface.

The lense i am using is a planeo-convex lens and i have my glass slide at 45 degrees my lamp is also a sodium!
this is a picture of my set up
 

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Well, by replacing air with water you decrease the intensity of the reflected light at both interfaces.
The reflection coefficient depends on the difference between the indices. If you reduce the difference more light will just get through, without being reflected.

What would you expect if you replace the water with glass of the same index as the lens and slide (without any air at the interface)?
 
emmalou said:
i changed the index from air to water to see the affects, yes i did byt it between the curved surface and the plane surface.

The lense i am using is a planeo-convex lens and i have my glass slide at 45 degrees my lamp is also a sodium!
this is a picture of my set up
As the light travels slower in the water, it is equivalent to having a bigger gap, and so the rings will be more closely spaced and harder to see.
 

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