http://image.zhihuishu.com/zhs/onlineexam/ueditor/201802/5f998d872c3d4886b04c1349a5e2cf63.png
举一反三
- 波长为<img src="http://image.zhihuishu.com/zhs/onlineexam/ueditor/201802/91ddb92399a343cc990e393ea7ae49e4.png" />的单色光垂直入射于光栅常数为d、缝宽为a、总缝数为N的光栅上。取<img src="http://image.zhihuishu.com/zhs/onlineexam/ueditor/201802/d02f9b0d40604921bb6eba164d27ae52.png" />，则决定出现主极大的衍射角<img src="http://image.zhihuishu.com/zhs/onlineexam/ueditor/201802/294d963ff1564c7e9c98a2ca06a7278c.png" />的公式可写成（ ）。 A: <img src="http://image.zhihuishu.com/zhs/onlineexam/ueditor/201802/7e2fd47a37564a53afe33f3fadb46a41.png" /> B: <img src="http://image.zhihuishu.com/zhs/onlineexam/ueditor/201802/2c25a6b55e74467992e1b3b1d02662d8.png" /> C: <img src="http://image.zhihuishu.com/zhs/onlineexam/ueditor/201802/f852c846c7b642f6bbcaf2bcfa75c310.png" /> D: <img src="http://image.zhihuishu.com/zhs/onlineexam/ueditor/201802/27465a93e5ca42d8a18f9a3222d0e52b.png" />
- http://image.zhihuishu.com/zhs/onlineexam/ueditor/201802/1bddce95fbb240e1bbbeee3a4a066c5d.png
- http://image.zhihuishu.com/zhs/onlineexam/ueditor/201802/e5c3ed68bc434cd28fefaabd46deec74.png
- http://image.zhihuishu.com/zhs/onlineexam/ueditor/201802/089a9124e2c045908926cf96a6027efe.png
- 如图所示，用一斜向上的力<img src="http://image.zhihuishu.com/zhs/onlineexam/ueditor/201802/2c66b17a89294028b013f78ac88214d8.png" />(与水平成30°角)，将一重为G的木块压靠在竖直壁面上，如果不论用怎样大的力F，都不能使木块向上滑动，则说明木块与壁面间的静摩擦系数m的大小为 <img src="http://image.zhihuishu.com/zhs/onlineexam/ueditor/201802/dce25bc1a82e4dd996be3f0109b2524a.png" /> A: <img src="http://image.zhihuishu.com/zhs/onlineexam/ueditor/201802/289aa51d07e34d4bb3dfeacd6a1ca096.png" /> B: <img src="http://image.zhihuishu.com/zhs/onlineexam/ueditor/201802/8a557aef21054265b69c406b27e26221.png" /> C: <img src="http://image.zhihuishu.com/zhs/onlineexam/ueditor/201802/e97a8667b31e41439e0cb168a9b4934f.png" /> D: <img src="http://image.zhihuishu.com/zhs/onlineexam/ueditor/201802/facdf89eaa084d3eb7af997874a8ddc0.png" />