已知氢原子的基态能量为E1 激发态能量En=E1/n2其中n=2，3，4…。用h表示普郎克常量，c表示真空中的光速。能使氢原子从第一激发态电离的光子的最大波长错误的为
A．-4hc/3E1
B．-2hc/E1
C．-4hc/ E1
D．-9hc/ E1
ABD
题目分析：第一激发态即第二能级，是能量最低的激发态，则有：
；
电离是氢原子从第一激发态跃迁到最高能级0的过程，需要吸收的光子能量最小为：
所以有：
，解的：
，故ABD错误，C正确．
让选错误的，故选ABD．
点评：本题主要考察了电离中涉及的氢原子的能级跃迁问题．同时明确光子能量、光速、频率、波长之间关系．
| 完形填空. | |||
| What is the best way to study? This is a very important question. Some Chinese students often 1 very hard 2 long hours. This is a 3 habit , but it is not a better way to study. A good student must 4 enough sleep, enough food and enough rest. Every 5 you 6 to take a walk or play basketball or ping-pong or sing a song, When you 7 to your studies, you'll find yourself 8 than before and you'll learn more. Perhaps we can 9 that learning English is like taking Chinese medicine, we mean that like Chinese medicine, the effects (效果) of your study _ 10 _ slowly but surely. Learn every day and effects will come just like Chinese medicine. | |||
| ( ) 1. A. play ( ) 2. A. at ( ) 3. A. best ( ) 4. A. have ( ) 5. A. month ( ) 6. A. want ( ) 7. A. begin ( ) 8. A. stronger ( ) 9. A. say ( ) 10. A. return | B. study B. in B. better B. do B. week B. hope B. return B. weaker B. guess B. come | C. sleep C. for C. good C. want C. hour C. need C. go C. strong C. talk C. give | D. think D. with D. bad D. make D. day D. wish D. are D. weak D. know D. get |