mooc答案类别订阅

第一章 单元测验

1、单选题：
‏关于互联网金融的发展，以下哪一个说法是错误的（）‍
选项：
A: 1995年互联网起步开始
B: 2003年电子商务元年
C: 2007年第三方支付元年
D: 2013年互联网金融元年
答案: 【 2007年第三方支付元年】点我阅读全文

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

第1章单元测验

1、单选题：
‍在国际连锁业协会以及西方各国政府的规定中，往往把经营（）家以上商店的零售业或者饮食业组织称为连锁商店。‏‍‏
选项：
A: 9
B: 15
C: 11
D: 20
答案: 【 11】点我阅读全文

测验题

1、单选题：

‏

‏选项：
A:
B:
C:
D:
答案: 【 】点我阅读全文

1.你真的认识文献吗？—文献线索判读（上）随堂测试题

1、单选题：
‌1、根据文献的特点，在研究课题中，做基础性的理论研究参考文献一般多用：‍‌‍
选项：
A: 期刊
B: 图书
C: 专利
D: 科技报告
答案: 【 图书】点我阅读全文

第一单元测试题

1、判断题：
‍只要歌唱得好，什么姿势并不重要。‎
选项：
A: 正确
B: 错误
答案: 【 错误】点我阅读全文

第二章单元测试

1、单选题：
‌梭伦是下列古希腊哪个城邦的的改革家（   ）‏
选项：
A: 斯巴达城邦
B: 雅典城邦
C: 罗马城邦
D: 西西里城邦
答案: 【 雅典城邦】点我阅读全文

请从FANBOYS (for and nor but or yet so) 中选取适当的连词填空

1、填空题：
‎请从FANBOYS (for and nor but or yet so) 中选取适当的连词填空‍‎It rained heavily last night         I did not go out for supper.‍
答案: 【 so】点我阅读全文

第一章单元作业测试

1、单选题：
​考虑力对物体作用的运动效应和变形效应，力是       。 ‏
选项：
A:  滑动矢量 
B:  自由矢量  
C: 定位矢量
D:   
答案: 【 定位矢量】点我阅读全文

第一章单元测验

1、单选题：
​计算机硬件能直接执行的是‌
选项：
A: 高级语言 
B: 机器语言
C: 汇编语言
D: 任何语言
答案: 【 机器语言】点我阅读全文