✔ 最佳答案
Q1 : How should I explain althought in the sources presence in fig.2 shown,it is still right for the def. of pt. source hence in the double slits experiment which acts as a source slit?
If you only limit yourself to two dimensions, each point source in fig.2 would produce a pattern. A line source, which is a source that made up of a vertical array of points, would then produce vertical bands of bright and dark fringes, as what is observed in the double-slit experiment.
Q2 : Will diffraction pattern form in this situation ?If yes ,will it be similar to Newton's Rings?
You could see the interference pattern of a hole on the following web-page. The pattern can be seen near the middle of the page.
http://www.itp.uni-hannover.de/~zawischa/ITP/diffraction.html
2011-04-10 13:32:31 補充:
Just to correct a typo. The first sentence in the answer to Q1, "If you only limit yourself to ONE dimension,..."
2011-04-10 13:34:53 補充:
Be aware that in the double-slit experiment, the slit width is assumed to be infinitely small. In practice, it should be smaller than or at least equal to the wavelength of light used. Otherwise, the "poin-source" assumption would not hold.