题目内容

试分析图19.14所示电路的工作情况。

查看答案

搜索结果不匹配？点我反馈

更多问题

什么是最小项？

如图3-30所示，一平面镜置于充满水的容器的底部，人俯视平面镜看自己的像，设眼睛高出水面h₁=10cm，而镜子在水面之下深h₂=66.5cm。试求眼睛在镜子中看起来与眼睛的距离(水的折射率为4/3)。

1.The teacher has requested the students to（）in red the words which have been spelled incorrectly.
2.The historians use the（）on the walls of ancient temples to guide them in their research.
3.During the interview,he asked me to（）what kind of things I do in my spare time.
4.A（）is the piece of paper on which your doctor writes an order for medicine and which you then give to a chemist or pharmacist to fill the order.
5.He（）his low mark to the noisy study environment.
6.My main reason for（）to New Scientist is to keep abreast of advances.in science.

与理想光学系统相比。实际光学系统的成像光束口径和成像范围都受到限制，多数系统存在渐晕现象。①渐晕是由于孔径光阑的拦光作用而产生的。②渐晕使成像平面的照度不均匀。③轴外点成像光束的宽度不只与孔径光阑有关，而且和渐晕光阑有关。④孔径光阑的位置影响轴上点成像光束的选择。