Why is it not possible to see the interference pattern of white light

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Discussion Overview

The discussion revolves around the visibility of interference patterns when using white light in a Young's double slit experiment. Participants explore the reasons why the interference pattern may not be clearly observed with white light compared to monochromatic sources, addressing both theoretical and practical aspects.

Discussion Character

  • Debate/contested
  • Conceptual clarification

Main Points Raised

  • Some participants propose that the overlapping of different wavelengths in white light leads to a washed-out interference pattern.
  • Others argue that while white light contains a range of colors, it is still possible to observe an interference pattern, with specific colors like blue and red appearing at the edges of the fringes.
  • A participant mentions that using monochromatic light sources, such as laser pointers, is a more straightforward method for demonstrating interference effects.
  • There is a contention regarding the interpretation of comments made about the use of white light versus monochromatic sources, with some participants feeling that certain remarks were insulting.
  • One participant recalls successfully observing interference patterns using car headlamp bulbs, suggesting that white light can indeed produce visible patterns under certain conditions.

Areas of Agreement / Disagreement

Participants express differing views on the visibility of interference patterns with white light, with some asserting it is possible while others emphasize the challenges posed by multiple wavelengths. The discussion remains unresolved regarding the clarity of these patterns when using white light.

Contextual Notes

Participants reference educational demonstrations and personal experiences, indicating that practical outcomes may vary based on the specific light sources used and experimental conditions.

5ymmetrica1
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'The colour seen when white light is used as a source for a Young’s double slit experiment are sometimes mistaken for the spectrum of visible light.'
Why is this not possible with a two slit interference pattern?

I know that the different wavelengths will all cause interference with each other, but is there a better explanation than this?
 
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5ymmetrica1 said:
'The colour seen when white light is used as a source for a Young’s double slit experiment are sometimes mistaken for the spectrum of visible light.'
Why is this not possible with a two slit interference pattern?

I know that the different wavelengths will all cause interference with each other, but is there a better explanation than this?

Because there are so many different wavelengths in white light that the interference pattern from each wavelength overlaps each other and washes out.

Zz.
 
Deleted following insulting reply.
 
Last edited:
technician said:
It is correct that white light consists of arrange of colours (wavelengths) but it is perfectly straightforward to produce 2slit interference pattern the fringes obtained are essentially white but 'blue' can be seen at the 'inner' edge of the fringes and 'red' can be seen at the outer edge. This is a standard demonstration at A level and details are given in A level textbooks.

That's sad, considering how easy and cheap it is nowadays to obtain a laser pointer with a good-enough monochromatic light source.

Zz.
 
ZapperZ said:
That's sad, considering how easy and cheap it is nowadays to obtain a laser pointer with a good-enough monochromatic light source.

Zz.

This is an insulting comment.. I have reported it and I have deleted my response.
 
Last edited:
technician said:
This is an insulting comment.. I have reported it and I have deleted my response.

Not sure what is "insulting" about that. You obviously read WAY differently than what I wrote.

The "sad" comment was directed at the situation, i.e. that one had to use a white light to demonstrate interference effects, rather than obtaining a simple, cheap, monochromatic light source. You appear to interpret it as being directed at your comment.

Zz.
 
5ymmetrica1 said:
'The colour seen when white light is used as a source for a Young’s double slit experiment are sometimes mistaken for the spectrum of visible light.'
Why is this not possible with a two slit interference pattern?

I know that the different wavelengths will all cause interference with each other, but is there a better explanation than this?

It is possible to see the pattern for white light with 2 slits...we did it at school using car head lamp bulbs.
 

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