用一束单色光照射处于基态的一群氢原子，这些氢原子吸收光子后处于激发态，并能发射光子，现测得这些氢原子发射的光子频率仅有三种，分别为
．
和
，且<<。则入射光子的能量应为（ ）
A．h
B．h
C．h（＋）
D．h
CD
本题考查氢原子能级公式和跃迁
根据氢原子能放出三种频率光，判断此时氢原子处在第几能级，然后计算从基态跃迁到该能级需要多少能量，计算能量时根据能级之简能量差和放出光子能量之间的关系计算．同时明确频率、波长、光速之间关系．
能放出三种光，说明此时氢原子处在第3能级，从第三能级跃迁到基态时放出光子能量为：E= h
，或者E= h（
＋
）．所以入射光子能量为E= h，或者E= h（＋）。
| 完形填空。 |
| Mr. Strong is a London taxi driver. The following talk is given by him. "I have been a taxi driver 1 nearly ten years. It's a nice job most of the time. You meet a lot of people. I always work at night, 2 there is too much traffic during the day. I go to work at 5:30 in the afternoon, and I usually 3 between 2:00 and 3:00 in the morning." "Some 4 things happened late at night. 5 day I was taking a woman home from a party. She had her little dog with her. When we got to her house, she found that she had lost her 6 . So I waited in the car 7 she climbed in through the windows." "I waited and waited. After half an hour of ringing the bell I decided to find out 8 was going on. I tied the dog to a tree and started to 9 in through the window. The next thing I knew was that the police came. They thought I was a thief." "Luckily the woman came downstairs. She 10 have gone to sleep and forgotten me and the dog!" |
| ( )1. A. in ( )2. A. if ( )3. A. go home ( )4. A. sad ( )5. A. The other ( )6. A. money ( )7. A. until ( )8. A. what ( )9. A. drive ( )10. A. will | B. for B. so B. go shopping B. good B. Another B. bag B. while B. which B. walk B. can | C. before C. though C. do sports C. strange C. The others C. box C. since C. who C. climb C. may | D. after D. because D. do housework D. disappointing D. Other D. key D. as soon as D. that D. run D. must |