1、 实验
1801年,(英)托马斯·杨
单色光 单孔屏 双孔屏 接收屏
4、光电效应--证明光具有粒子性
3、光的电磁说--(英)麦克斯韦,光是一种电磁波
2、波动说--(荷兰)惠更斯、(法)菲涅尔,光在“以太”中以某种振动向外传播
成功--反射、折射、 干涉、衍射
困难--光电效应、康普顿效应、偏振
19世纪以前,微粒说一直占上风
(1) 人们习惯用经典的机械波的理论去理解光的本性。
(2) 牛顿的威望
(3) 波动理论本身不够完善 (以太、惠更斯无法科学的给出周期和波长的概念)
1、 微粒说--(牛顿)认为个光是粒子流,从光源出发,在均匀介质中遵循力学规律做匀速直线运动。
成功--直线传播(匀速直线运动)、反射(经典粒子打在界面上)
困难--干涉,衍射(波的特性),折射(粒子受到界面的吸引和排斥:折射角、不能一视同仁),光线交叉
70. John caught a cold on Saturday and ______ in bed ever since.
A. was B. has been C. is D. have been
时态和语态专练答案
1-5 BBBCC 6-10 BABAB 11-15 DDABD 16-20 CCABD
21-25 CDAAB 26-30 CBDAD 31-35 CDACA 36-40ABADC
41-45 DDCCD 46-50 BBDCB 51-55 CADCB 56-60 ADDAA
61-65 ABACB 66-69 CDADB
69. --- How does your second-hand car run?
--- It ___ run all right, but it is being repaired.
A. has B. had C. doesn’t D. used to
68. ----I thought you were proud of the work I _____.
----I’m afraid not . You’d better change it for another.
A. do B. had done C. did D .would do
67. In 1960, this was the longest bridge that ___.
A. was ever built B. had ever built C. has ever been built D. had ever been built
66. He ____ a model plane the whole morning. I supposed he would also do some washing.
A. made B. has made C. was making D. has made
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