| 单词 | expansivity |
| 释义 | expansivity(thermal expansion) 1Linear expansivity is the fractional increase in length of a specimen of a solid, per unit rise in temperature. If a specimen increases in length from l1 to l2 when its temperature is raised θ°, then the expansivity (α) is given by: l2 = l1(1 + αθ). This relationship assumes that α is independent of temperature. This is not, in general, the case and a more accurate relationship is: l2 = l1(1 + aθ + bθ2 + cθ3…) , where a, b, and c are constants.2Superficial expansivity is the fractional increase in area of a solid surface caused by unit rise in temperature, i.e. A2 = A1(1 + ßθ) , where ß is the superficial expansivity. To a good approximation ß = 2α.3Volume expansivity is the fractional increase in volume of a solid, liquid, or gas per unit rise in temperature, i.e. V2 = V1(1 + γθ) , where γ is the cubic expansivity and γ = 3α. For liquids, the expansivity observed directly is called the apparent expansivity as the container will also have expanded with the rise in temperature. The absolute expansivity is the apparent expansivity plus the volume expansivity of the container. For the expansion of gases, see Charles' Law. |
| 随便看 |
|
物理辞典收录了3346条物理词条，基本涵盖了常用物理知识及物理英语单词词组的翻译及用法，是物理学习的有利工具。