题目内容
如图所示, 真空中有一下表面镀有反射膜的平行玻璃砖,其折射率n=
。一束单色光与界面成θ=45°角斜射到玻璃砖上表面上,最后在玻璃砖的右侧面竖直光屏上出现了两个光点A和B,A和B相距h=2.0 cm.已知光在真空中的传播速度c=3.0×108 m/s,试求:
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/201408250053269893615.jpg)
①该单色光在玻璃砖中的传播速度.
②玻璃砖的厚度d.
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825005326958344.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/201408250053269893615.jpg)
①该单色光在玻璃砖中的传播速度.
②玻璃砖的厚度d.
①
×108 m/s②
cm.
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825005327004495.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825005327020344.png)
试题分析:①由折射率公式n=
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825005327020346.png)
解得:v=
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825005327036377.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825005327004495.png)
②由折射率公式n=
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825005327176630.png)
解得sinθ2=
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825005327192338.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/201408250053272075328.jpg)
作出如图所示的光路,△CDE为等边三角形,四边形ABEC为等腰梯形,CE=AB=h.
玻璃的厚度d就是边长为h的等边三角形的高.(1分)
故d=hcos 30°=
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825005327238453.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825005327020344.png)
![](http://thumb2018.1010pic.com/images/loading.gif)
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