题目内容
如图13-1-10所示,一束平行单色光的宽度为d,由空气射入某液体中,入射角为45°,已知该液体的折射率为
,则光束在液体中传播时的宽度d′=_________.
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/201408241208001494827.png)
图13-1-10
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824120800056336.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/201408241208001494827.png)
图13-1-10
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824120800227581.png)
光束传播的光路图如图20所示,设折射角为r,
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/201408241208002742723.png)
图20
由折射定律:
,将θ=45°,
代入得r=30°.
由图知:OO′=
,同理d′=OO′·cosr=
·cosr=d·cos30°/cos45°=![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824120800461587.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/201408241208002742723.png)
图20
由折射定律:
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824120800305659.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824120800337464.png)
由图知:OO′=
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824120800368572.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824120800368572.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824120800461587.png)
![](http://thumb2018.1010pic.com/images/loading.gif)
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