题目内容
如下图所示,一束光线以60°的入射角射到一水平放置的平面镜上,反射后在正上方与平面镜平行的光屏上留下一光点P.现将一块上下两面平行的透明体平放在平面镜上,如图中虚线所示,则进入透明体的光线经平面境反射后再从透明体的上表面射出,打在光屏上的光点P′,与原来相比向左平移了3.46 cm,已知透明体对光的折射率为.
(1)作出后来的光路示意图,标出P′位置;
(2)透明体的厚度为多大?
(3)光在透明体里运动的时间多长?![](http://thumb.1010pic.com/pic2/upload/papers/20140824/201408241358478367588.png)
(1)作出后来的光路示意图,标出P′位置;
(2)透明体的厚度为多大?
(3)光在透明体里运动的时间多长?
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/201408241358478367588.png)
(1)见解析(2) 2×10-10 s
(1)光路图如下图所示.
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/201408241358478832763.jpg)
(2)由折射定律sin α=nsin β代入数据解得:
β=30°
设透明体的厚度为d
=
=
-
=2dtan α-2dtan β
=2
d-
d=2
cm
d=1.5 cm.
(3)光在透明体里运动的速度:v=![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824135848491377.png)
光在透明体里运动的路程:s=2·![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824135848569667.png)
光在透明体里运动的时间是: t=
=
=
=2×10-10 s.
本题考查折射定律,根据光路图、折射定律求出角度大小,再由几何关系求出运动时间
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/201408241358478832763.jpg)
(2)由折射定律sin α=nsin β代入数据解得:
β=30°
设透明体的厚度为d
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824135847898348.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824135847929419.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824135847992404.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824135848039430.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824135847898348.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824135848257344.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824135848335503.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824135848257344.png)
d=1.5 cm.
(3)光在透明体里运动的速度:v=
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824135848491377.png)
光在透明体里运动的路程:s=2·
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824135848569667.png)
光在透明体里运动的时间是: t=
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824135848631345.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824135848725781.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824135848787840.png)
本题考查折射定律,根据光路图、折射定律求出角度大小,再由几何关系求出运动时间
![](http://thumb2018.1010pic.com/images/loading.gif)
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