mooc答案类别订阅

第一周 单元测验

1、单选题：
‌本单元提到电视评论的繁荣，始于央视2003年（  ）频道的开播。‎
选项：
A: 中文国际
B: 社会与法
C: 新闻
D: 财经
答案: 【 新闻】点我阅读全文

1.1有机化合物和有机化学随堂测验

1、单选题：
‍下列化合物中，不是有机化合物的是（        ）  ‌
选项：
A: 叶绿素
B:  氯仿   
C: 尿素  
D:  氨气
答案: 【  氨气】点我阅读全文

第一章单元测验

1、单选题：

‏若，则

‍选项：
A: 4.
B: -4.
C: 8.
D: -8.
答案: 【 -8.】点我阅读全文

第一周单元测验

1、单选题：
‏测量细菌大小的单位是‏
选项：
A: um
B: mm
C:  mu
D: nm
答案: 【 um】点我阅读全文

第一章单元检测

1、单选题：
‏叶绿素强烈吸收的波段是？‏
选项：
A: 微波波段
B: 可见光波段
C: 近红外波段
D: 紫外波段
答案: 【 可见光波段】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

课后作业

1、判断题：

‌一维弦的自由振动方程是。

‌选项：
A: 正确
B: 错误
答案: 【 正确】点我阅读全文

《马路天使》随堂测验

1、单选题：
‎（）是最具法国气质的诗意现实主义大师。‎‎‎
选项：
A: 特吕弗
B: 雷内·克莱尔
C: 戈达尔
D: 维斯康蒂
答案: 【 雷内·克莱尔】点我阅读全文

单元测验

1、单选题：
‍传切配合是进攻队员之间利用( )技术组成的简单配合。 ‍‍‍
选项：
A: 传球和运球
B: 运球和切入
C: 传球和切入
D: 切入和投篮
答案: 【 传球和切入】点我阅读全文

中国古代军事思想测试

1、单选题：
‎春秋时期，吴国用了（）的军事思想，打败了强大的楚国。‌
选项：
A: 吴子
B: 孙武
C: 尉缭子
D: 老子
答案: 【 孙武】点我阅读全文