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第一章量子力学基础第一讲

关于品优波函数

1、多选题：
‍满足（     ）条件的波函数才能称为品优波函数。‏
选项：
A: 单值
B: 连续
C: 有限
D: 归一化
答案: 【 单值;
连续;
有限】点我阅读全文

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第一章 管理学导论

1.1 测试

1、单选题：
‍管理的主体是（     ）‌
选项：
A: 管理者
B: 组织
C: 个人  
D: 管理机构
答案: 【 管理者】点我阅读全文

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章节一品牌触角向内也向外

单元测试1

1、单选题：
​英文单词“brand”最早被挪威人用来区分什么？‍
选项：
A: 手工艺者的作品
B: 家畜和其他需要与别人区别的私有财产
C: 不同品种的家畜
D: 不同品种的农作物
答案: 【 家畜和其他需要与别人区别的私有财产】点我阅读全文

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第1讲 水处理大师修行须知-绪论1

第1讲 测试题

1、单选题：
​ 城市给水系统主要包括（    ）。‌​‌
选项：
A: 取水工程、净水工程、输配水工程。
B: 取水工程、净水工程、饮水工程。
C:  输水工程、净水工程、配水工程。
D: 配水工程、净水工程、饮水工程。
答案: 【 取水工程、净水工程、输配水工程。】点我阅读全文

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第一章概论

1.1绪论习题

1、单选题：
‎下面哪种传输媒介的传输容量最大？‌
选项：
A: 电缆线；
B: 微波；
C: 光纤；
D: 卫星。
答案: 【 光纤；】点我阅读全文

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第1章流体流动

基本概念和物理量

1、单选题：
‎（单选）以如下哪项为基准的压强称为绝对压强（ ）‏
选项：
A: 当地大气压
B: 标准大气压 
C: 绝对0压强
D: 那三个都不是
答案: 【 绝对0压强】点我阅读全文

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Lesson2

Scanning

1、单选题：
​Read the passage "The Discovery of X-rays" quickly and choose the paragraph(s) which contain(s) the answer(s). You may choose more than one answer for question 3. ‏​‏The Discovery of X-rays‏​ ‏Par. 1 Except for a brief description of the Compton effect, and a few other remarks, we have postponed the discussion of X-rays until the present chapter because it is particularly convenient to treat X-ray spectra after treating optical spectra. Although this ordering may have given the reader a distorted impression of the historical importance of X-rays, this impression will be corrected shortly as we describe the crucial role played by X-rays in the development of modern physics.‏Par. 2 X-rays were discovered in 1895 by Roentgen while studying the phenomena of gaseous discharge. Using a cathode ray tube with a high voltage of several tens of kilovolts, he noticed that salts of barium would fluoresce when brought near the tube, although nothing visible was emitted by the tube. This effect persisted when the tube was wrapped with a layer of black cardboard. Roentgen soon established that the agency responsible for the fluorescence originated at the point at which the stream of energetic electrons struck the glass wall of the tube. Because of its unknown nature, he gave this agency the name X-rays. He found that X-rays could manifest themselves by darkening wrapped photographic plates, discharging charged electroscopes, as well as by causing fluorescence in a number of different substances. He also found that X-rays can penetrate considerable thicknesses of materials of low atomic number, whereas substances of high atomic number are relatively opaque. Roentgen took the first steps in identifying the nature of X-rays by using a system of slits to show that (1) they travel in straight lines, and that (2) they are uncharged, because they are not deflected by electric or magnetic fields.‏Par. 3 The discovery of X-rays aroused the interest of all physicists, and many joined in the investigation of their properties. In 1899 Haga and Wind performed a single slit diffraction experiment with X-rays which showed that (3) X-rays are a wave motion phenomenon, and, from the size of the diffraction pattern, their wavelength could be estimated to be 10-8 cm. In 1906 Barkla proved that (4) the waves are transverse by showing that they can be polarized by scattering from many materials.‏Par. 4 There is, of course, no longer anything unknown about the nature of X-rays. They are electromagnetic radiation of exactly the same nature as visible light, except that their wavelength is several orders of magnitude shorter. This conclusion follows from comparing properties 1 through 4 with the similar properties of visible light, but it was actually postulated by Thomson several years before all these properties were known. Thomson argued that X-rays are electromagnetic radiation because such radiation would be expected to be emitted from the point at which the electrons strike the wall of a cathode ray tube. At this point, the electrons suffer very violent accelerations in coming to a stop and, according to classical electromagnetic theory, all accelerated charged particles emit electromagnetic radiations. We shall see later that this explanation of the production of X-rays is at least partially correct.‏Par. 5 In common with other electromagnetic radiations, X-rays exhibit particle-like aspects as well as wave-like aspects. The reader will recall that the Compton effect, which is one of the most convincing demonstrations of the existence of quanta, was originally observed with electromagnetic radiation in the X-ray region of wavelengths.‏​‏​When were X-rays discovered?‏
选项：
A: Par. 1
B: Par. 2
C: Par. 3
D: Par. 4
E: Par. 5
答案: 【 Par. 2】点我阅读全文

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第一周 第一章 绪论；第三章 儿童保健

第一周 单元测试

1、单选题：
‎正常情况下，胎儿期是指从受精卵到胎儿出生约‍
选项：
A: 39周
B: 38周
C: 42周
D: 40周
答案: 【 40周】点我阅读全文

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第一章 先秦至汉代文学选读

随堂练习

1、单选题：
​屈原创立了（）这种文体（也称“骚体”）。‌
选项：
A: 离骚
B: 楚辞
C: 辞赋
D: 诗赋
答案: 【 楚辞】点我阅读全文

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