在数学上,“比”(或比值)是一个抽象的概念,且局限定义于同类量之比。但在物理学中,某些物理量和物理定律中的“比”,却含有它深刻的物理意义。例如: 一、用比定义物质的物理性质,如密度、比热、电场强度、电势、折射率等。二、用比说明某些物理量之间的关系, Mathematically, “ratio” (or ratio) is an abstract concept, and the limits are defined in the same kind of ratio. But in physics, the “ratio” of some physical quantities and laws of physics contains its profound physical meaning. For example: First, than to define the physical properties of matter, such as density, specific heat, electric field strength, potential, refractive index and so on. Second, than to illustrate the relationship between some of the physical quantities,