mooc答案类别

第2周计算

小测验

1、填空题：
写出以下代码执行后，t1和t2的值，以空格隔开：‌int a=14;‌int t1 = a++;‌int t2 = ++a;‌
答案: 【 14 16】点我阅读全文

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第一章哲学与科技的智慧

第一章哲学与科技的智慧单元测验

1、单选题：
‌关于西方对中国有无哲学进而有无智慧看法概括起来有三种，其中“中国中心论”的代表人物是（   ）。‎
选项：
A: 伏尔泰
B: 黑格尔
C: 德里达
D: 雅斯贝斯
答案: 【 伏尔泰】点我阅读全文

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第四章电离辐射生物效应

第四章单元测试

1、单选题：
​以下属于随机性效应是‌​‌
选项：
A: 癌症
B: 白血病
C: 白内障
D: 射线照射引发皮肤损伤
答案: 【 癌症】点我阅读全文

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第十章碱金属和碱土金属元素

第九章、第十章单元测试

1、单选题：
 在下列各种酸中酸性最强的是______。‍‌‍
选项：
A: H2SO4  
B: H3PO4  
C: HClO4    
D: H3AsO4
答案: 【 HClO4    】点我阅读全文

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第一讲半导体导论

01-02杂质半导体

1、单选题：
​N型半导体中的多子是（）。‎
选项：
A: 电子
B:  空穴
C: 正离子
D:  负离子
答案: 【 电子】点我阅读全文

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Lesson 2

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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第一单元

第一单元测验

1、单选题：
‍以下哪项基本技术是学习网球技术最先需要掌握的？‏
选项：
A: 发球技术
B: 正手击球技术
C: 截击球技术
D: 反手技术
答案: 【 正手击球技术】点我阅读全文

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1.巴赫复调钢琴作品的演奏

巴赫复调钢琴作品的演奏单元测验

1、填空题：
‍巴赫被称为_______​
答案: 【 西方音乐之父】点我阅读全文

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第一章 绪论

1.1 随堂测验

1、单选题：
​《中华人民共和国环境保护法》所称的环境是指影响人类生存和发展的各种（）的总体。‍
选项：
A: 自然因素和社会因素
B: 社会因素和文化因素
C: 经济因素和自然因素 
D: 天然的和经过人工改造的自然因素
答案: 【 天然的和经过人工改造的自然因素】点我阅读全文

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第一讲 绪论

第一章单元测验

1、判断题：
‎基底埋深小于5m是浅基础的本质特征。‎
选项：
A: 正确
B: 错误
答案: 【 错误】点我阅读全文

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