查看完整版本 : question about air wedge (urgent , please help ! )

190303458 2012-5-4 05:13 AM

question about air wedge (urgent , please help ! )

[attach]1730792[/attach]

Given wavelength=590nm , separation between dark fringes=1.3mm , find the thickness of the paper ?

jmlo 2012-5-4 11:42 AM

回覆 1# 的帖子

Please read the example in the following page, and you will get the idea how this question can be solved. :loveliness:

[url]http://www.schoolphysics.co.uk/age16-19/Wave%20properties/Interference/text/Wedge_fringes/index.html[/url]

190303458 2012-5-6 02:27 AM

Why the vertical height for 57.7 fringes =[5.8x10(^-7)x57.7]/2 in the example?
Also , in my question , whether the no. of dark fringes = 200/1.3 ?

jmlo 2012-5-6 12:25 PM

回覆 3# 的帖子

Note that there is a phase change when the light is reflected by the surface of the bottom plate. Therefore, in order to see a constructive interference (i.e., bright fringe) on the upper plate, the path difference (i.e., the vertical height) has to be equal to (m+1/2)l which is (2m+1)l/2.
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查看完整版本: question about air wedge (urgent , please help ! )