智慧树慕课答案
1、单选题：
下列对点元素特性的描述正确的是（ ）
选项：
A: 在设计中的点有不同的形状、质感、大小、色彩、肌理等属性
B: 在造型中，最好用单点设计，多点会造成视觉混乱的效果
C: 圆点最能给人点的感觉，所以点的形状最好是圆的
D: 点在造型中的位置是固定不变的
答案: 【 在设计中的点有不同的形状、质感、大小、色彩、肌理等属性】点我阅读全文
1、单选题：
不是力的三要素之一。
选项：
A: 力的大小
B: 力的方向
C: 力的作用点
D: 力的数量
答案: 【 力的数量】点我阅读全文
1、单选题：
下列各项中，对会计主体表述恰当的是（ ）。
选项：
A: 一个会计主体必然是一个法律主体
B: 会计主体确立了会计核算的时间范围
C: 会计主体确立了会计核算的空间范围
D: 会计主体为会计核算提供了计量手段
答案: 【 会计主体确立了会计核算的空间范围】点我阅读全文
1、单选题：
《大明律》和唐律相比，形式上最大的变化是（ ）。
选项：
A: 12篇改为7篇
B: 将律条分为213门
C: 将刑事法律和民事法律分开
D: 将实体法和程序法分开
答案: 【 12篇改为7篇】点我阅读全文
1、单选题：
隧道端部修建的为保护洞口和排放流水的挡土墙式结构称之为（）。
选项：
A: 排水沟
B: 挡土墙
C: 洞门
D: 端墙
答案: 【 洞门】点我阅读全文
1、单选题：
下列不属于危机基本特征的是（ ）。
选项：
A: 危害性
B: 不确定性
C: 超常性
D: 不可转化性
答案: 【 不可转化性】点我阅读全文
1、单选题：
将二进制数1010101101.1转换成十六进制数为 。
选项：
A: 2AD.1H
B: 2AC.8
C: 2AC.4
D: 2AD.8
答案: 【 2AD.8】点我阅读全文
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
1、单选题：
螺纹M20×1.5中M指
选项：
A: 普通螺纹
B: 梯形螺纹
C: 锯齿形螺纹
D: 55°非密封管螺纹
答案: 【 普通螺纹】点我阅读全文
1、多选题：
色粉还可以用来表现哪些材质？
选项：
A: 玻璃材质
B: 木材质
C: 金属材质
D: 塑料材质
答案: 【 玻璃材质;
木材质;
金属材质;
塑料材质】点我阅读全文