Re: Thomas Young's experiment

[Charles Bell <charbell@BELLSOUTH.NET>]

Are you all aware of the article in November 2003 issue of American Journal
of Physics, page 1196, Huygen's principle and Young's experiment in the
propagation of light beams?

At 06:15 PM 11/1/2003, you wrote:
> On Saturday, Nov 1, 2003, at 12:32 Bernard Cleyet wrote:
>
>  > try replacing the card with a strip whose
>  > depth is the same as its width.
>
> I am not performing an experiment. Why would the
> length of the card slip (which divides a beam from
> a pinhole into two separate parts) have to play a
> role? I suppose the slip card was black in order to
> minimize stray light. What is wrong with thinking that
> the card should act as if it were a wire?
>
> Unfortunately, I was not able to figure out what
> fraction of the beam area was actually covered by
> the card. There were no illustrations in Young's
> paper. To act as a single slit each uncovered area
> was probably very narrow. Thus the slip card
> shadow was probably at least 90% of the area of
> the diverging beam.
>
> In a single-wire experiment the situation is usually
> opposite; the area of the wire is a small part of the
> beam area. I can not prove it but I suspect that in
> going from one extreme to another one must be able
> to observe a transition from "peaks of equal widths"
> to a typical diffraction pattern -- a "central strong
> peak about twice as wide as other (weaker) peaks."
> That may be an experiment worth performing.
> Ludwik Kowalski