【多选题】光电效应的实验规律有哪些?
A.
光电子的初动能随入射光的频率上升而线性增大,与入射光强无关。
C.
如果入射光的频率低于该金属的截止频率,则无论入射光强多大,都不会使这种金属产生光电效应。
D.
单位时间内逸出金属表面的光电子数,与入射光强成正比。
【单选题】If you visit Cape Verde, you will find ______ .
A.
no people on the six smallest islands
B.
people only on the ten main islands
C.
about 200 people on every square mile of land
D.
people on all the islands except Santa Luzia
【单选题】you go, you’ll find people working hard to rebuild their city.
【单选题】You will find it hard to make friends with people _______________.
C.
without real love for them
【单选题】目前主流的民用无人机所采用的动力系统通常为活塞式发动机和 两种。
【单选题】.Nowhere else in the world _________ more friendly people than in China.
B.
can you be able to find
【单选题】You can turn to different kinds of people, dictionaries or maps, to find out what you wish to know.