Newton's Rings: Darker or Brighter Central Spot?

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In summary, the conversation discusses the formation of Newton's rings and the resulting dark or bright spot at the central point of contact. It is mentioned that the thin layer of air at the contact point causes a phase shift of 180° and results in a dark spot. The use of transmission as a method for creating the rings is also mentioned.
  • #1
oreo
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If light is transmitted at a point of contact in Newton's rings. The central spot will be darker or brighter?
 
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  • #2
If you understand how Newtons rings are formed, what do you think and why?
 
  • #3
CWatters said:
If you understand how Newtons rings are formed, what do you think and why?
Actually I can't understand what the word "transmission at contact point" here means. I know that there is thin layer of air at contact point due to which there is phase shift of 180° which results in dark point at mid.
 
  • #5


The central spot in Newton's rings experiment is determined by the interference of light waves at the point of contact between a convex lens and a flat glass surface. This interference results in a series of concentric rings, with the central spot being the point of maximum constructive interference.

The brightness or darkness of the central spot depends on the relative phase of the light waves at the point of contact. If the waves are in phase, they will produce a brighter central spot. Conversely, if they are out of phase, they will produce a darker central spot.

Therefore, the brightness or darkness of the central spot is not determined solely by the transmission of light at the point of contact, but rather by the interference of light waves. The specific conditions of the experiment, such as the thickness of the air film between the lens and the glass surface, will affect the phase of the light waves and ultimately determine whether the central spot is darker or brighter.
 

Related to Newton's Rings: Darker or Brighter Central Spot?

1. What are Newton's Rings?

Newton's Rings are a set of concentric, alternating light and dark rings that are observed when a plano-convex lens is placed on top of a flat glass surface with a thin layer of air in between.

2. Why is there a central spot in Newton's Rings?

The central spot in Newton's Rings is caused by the interference of light waves that are reflected from the top and bottom surfaces of the thin air layer between the lens and the glass surface. This results in a constructive interference at the center, producing a brighter spot.

3. Can the central spot change in brightness?

Yes, the central spot can change in brightness depending on the thickness of the air layer between the lens and the glass surface. If the air layer becomes thicker, the central spot will become darker. If the air layer becomes thinner, the central spot will become brighter.

4. What factors can affect the appearance of Newton's Rings?

The appearance of Newton's Rings can be affected by the quality of the lens and glass surface, the thickness of the air layer, the color of the light source, and the angle of incidence of the light on the surfaces.

5. What are some practical applications of Newton's Rings?

Newton's Rings have practical applications in measuring the flatness of surfaces, testing the quality of lenses, and determining the thickness of very thin films. They are also used in the design and calibration of optical instruments and devices.

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