A:光照时间越长光电流越大
B:入射光的光强一定时,频率越高,单位时间内逸出的光电子数就越多
C:金属钠的每个电子可以吸收一个或一个以上的光子,当它积累的动能最够大时,就能逸出金属
D:不同频率的光照射同一种金属时,频率越高,光电子的最大初动能越大
阅读理解
A: Do you have new teachers, Tom?
B: Yes.
A: Who are they?
B: Mr. Lin and Mr. Sun.
A: Are they young?
B: Mr. Lin is young, but Mr. Sun isn't.
A: Is Mr. Lin a university student?
B: Yes, he's very funny.
A: Is Mr. Sun strict?
B: Yes, but we all like him.
—Which is _______, the Yangtze River or the Yellow River?
—The Yangtze River, of course.