Would white light waves act as same as monochromatic waves in double slit experiment?
If not, what pattern would be seen on the screen?
[Physics] Would white light waves act as same as monochromatic waves in double slit experiment
double-slit-experimentelectromagnetic-radiationinterferencevisible-light
Related Solutions
The purpose of the double slits is to split the incoming wave front of a given frequency wave and so in effect you have two coherent sources, which are the slits, emitting light of that wavelength.
As the sources are coherent when the light from those sources overlap an interference pattern is formed.
Light of each wavelength coming through the slits produces its own interference pattern whose size depends on the wavelength of the light.
The zero order fringes (no path difference between the slits) are independent of the wavelength and so will occur at the same position.
If white light is incident on the double skits then that zero order fringe will be white.
The blue light fringes will have a spacing which is less than that for red light and so the first order fringes (one wavelength path difference) will occur in slightly different positions.
So the first order fringe will be relatively broad and bluish nearest the zero order fringe and reddish on the other side.
As one goes further away from the zero order fringe the displacement of the various colours becomes greater so that after a few fringes there is no clear fringe pattern.
I would describe the colors closest to the white central maximum as yellow (absence of blue) and magenta (absence of green). There is no "farthest" fringe, but next one sees a band of cyan (absence of red). These are complementary colors of the primary ones.
It has to do with the pigments in our eyes. Cameras and displays try to match these with their RGB channels. Here is an image I made, using a camera without a lens, using a $20\ \mu$m slit in the lens cap. I also decomposed the slit image in the separate color channels:
https://commons.wikimedia.org/wiki/File:Diffraction_sunlight_-_color_channels.jpg
Best Answer
White light consists of many wavelengths. Hence, the interference pattern using white light appears different than that for monochromatic light. At the center point, all the waves travel the same length and hence no path difference is produced at the center point. Thus at the center point we get the maxima of all wavelengths and we obtain the maximum for white light at the center point. Slightly above or below the center point the fringes will be coloured. Watch this video for visualising this: http://www.youtube.com/watch?v=GEqwRBjHdwc